阅读说明：本技术 逆变器控制装置、逆变设备及控制方法 (Inverter control device, inverter equipment and control method ) 是由 林镇煌 何宏伟 黄凯伦 于 2021-07-08 设计创作，主要内容包括：本发明适用于逆变器技术领域,提供了逆变器控制装置、逆变设备及控制方法,其中,逆变器控制装置,用于控制飞跨电容型逆变器工作,包括第一开关模块和控制模块；第一开关模块受控于控制模块；第一开关模块用于连接在飞跨电容型逆变器的直流电源的正极和飞跨电容型逆变器的第一飞跨电容的第一端之间,和/或,用于连接在直流电源的负极和第一飞跨电容的第二端之间；控制模块用于在飞跨电容型逆变器启动时,控制第一开关模块和控制飞跨电容型逆变器的第一逆变桥,以使直流电源通过第一回路为第一飞跨电容充电。本发明可以实现飞跨电容型逆变器充电缓启,降低器件的选型要求。(The invention is suitable for the technical field of inverters and provides an inverter control device, an inverter device and a control method, wherein the inverter control device is used for controlling a flying capacitor type inverter to work and comprises a first switch module and a control module; the first switch module is controlled by the control module; the first switch module is used for being connected between the positive pole of a direct-current power supply of the flying capacitor type inverter and the first end of a first flying capacitor of the flying capacitor type inverter, and/or is used for being connected between the negative pole of the direct-current power supply and the second end of the first flying capacitor; the control module is used for controlling the first switch module and the first inverter bridge of the flying capacitor type inverter when the flying capacitor type inverter is started, so that the direct-current power supply charges the first flying capacitor through the first loop. The invention can realize the charging slow start of the flying capacitor type inverter and reduce the type selection requirement of the device.)

1. The inverter control device is used for controlling the flying capacitor type inverter to work and comprises a first switch module and a control module; the first switch module is controlled by the control module;

the first switch module is used for being connected between the positive pole of a direct-current power supply of the flying capacitor type inverter and the first end of a first flying capacitor of the flying capacitor type inverter, and/or is used for being connected between the negative pole of the direct-current power supply and the second end of the first flying capacitor;

when the first switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the first flying capacitor, or is used for being connected between the negative electrode of the direct-current power supply and the second end of the first flying capacitor, the control module is used for controlling the first switch module and the first inverter bridge of the flying capacitor type inverter when the flying capacitor type inverter is started, so that the direct-current power supply, the first switch module, the first inverter bridge and the first flying capacitor form a first loop, and the direct-current power supply charges the first flying capacitor through the first loop;

when the first switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the first flying capacitor and is used for being connected between the negative electrode of the direct-current power supply and the second end of the first flying capacitor, the control module is used for controlling the first switch module when the flying capacitor type inverter is started, so that the direct-current power supply, the first switch module and the first flying capacitor form a second loop, and the direct-current power supply charges the first flying capacitor through the second loop;

the control module is further configured to control the first switch module to be turned off and control the first inverter bridge to start working when it is detected that the voltage across the first flying capacitor is not less than a first voltage; after the first switch module is switched off, the direct current power supply provides the first voltage to the first flying capacitor.

2. The inverter control apparatus of claim 1, wherein the first switching module includes a first current limiting unit and a first switching unit; the second end of the first current limiting unit is connected with the first end of the first switch unit; the first switch unit is controlled by the control module;

if the first switch module is connected between the anode of the direct-current power supply of the flying capacitor type inverter and the first end of the first flying capacitor of the flying capacitor type inverter, the first end of the first current limiting unit is connected with the anode of the direct-current power supply, and the second end of the first switch unit is connected with the first end of the first flying capacitor;

if the first switch module is connected between the negative electrode of the direct-current power supply and the second end of the first flying capacitor, the first end of the first current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the first switch unit is connected with the second end of the first flying capacitor;

the control module is further configured to control the first switch unit and the first inverter bridge when the flying capacitor type inverter is started, so that the dc power supply, the first switch unit, the first current limiting unit, the first inverter bridge, and the first flying capacitor form the first loop, and the dc power supply charges the first flying capacitor through the first loop.

3. The inverter control apparatus of claim 1, wherein the first switching module includes a second current limiting unit, a second switching unit, a third switching unit, and a third current limiting unit; the second end of the second current limiting unit is connected with the first end of the second switch unit; a second end of the third current limiting unit is connected with a first end of the third switching unit; the second switch unit and the third switch unit are controlled by the control module;

if the first switch module is connected between the positive electrode of the direct-current power supply and the first end of the first flying capacitor and between the negative electrode of the direct-current power supply and the second end of the first flying capacitor, the first end of the second current limiting unit is connected with the positive electrode of the direct-current power supply, the second end of the second switch unit is connected with the first end of the first flying capacitor, the first end of the third current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the third switch unit is connected with the second end of the first flying capacitor;

the control module is further configured to control the second switch unit and the third switch unit when the flying capacitor type inverter is started, so that the dc power supply, the second switch unit, the second current limiting unit, the first flying capacitor, the third switch unit and the third current limiting unit form the second loop, and the dc power supply charges the first flying capacitor through the second loop.

4. The inverter control apparatus according to any one of claims 1 to 3, characterized in that the apparatus further comprises a second switching module and a third switching module; the second switch module and the third switch module are controlled by the control module;

the second switch module is used for being connected between the positive pole of the direct-current power supply and the first end of a second flying capacitor of the flying capacitor type inverter, and/or is used for being connected between the negative pole of the direct-current power supply and the second end of the second flying capacitor;

when the second switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the second flying capacitor, or is used for being connected between the negative electrode of the direct-current power supply and the second end of the second flying capacitor, the control module is used for controlling the second switch module and the second inverter bridge of the flying capacitor type inverter when the flying capacitor type inverter is started, so that the direct-current power supply, the second switch module, the second inverter bridge and the second flying capacitor form a third loop, and the direct-current power supply charges the second flying capacitor through the third loop;

when the second switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the second flying capacitor and is used for being connected between the negative electrode of the direct-current power supply and the second end of the second flying capacitor, the control module is used for controlling the second switch module when the flying capacitor type inverter is started, so that the direct-current power supply, the second switch module and the second flying capacitor form a fourth loop, and the direct-current power supply charges the second flying capacitor through the fourth loop;

the control module is further configured to control the second switch module to be turned off and control the second inverter bridge to start working when it is detected that the voltage across the second flying capacitor is not less than the first voltage; after the second switch module is switched off, the direct current power supply provides the first voltage to the second flying capacitor;

the third switch module is used for being connected between the positive electrode of the direct current power supply and the first end of a third flying capacitor of the flying capacitor type inverter, and/or is used for being connected between the negative electrode of the direct current power supply and the second end of the third flying capacitor;

when the third switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the third flying capacitor, or is used for being connected between the negative electrode of the direct-current power supply and the second end of the third flying capacitor, the control module is used for controlling the third switch module and a third inverter bridge of the flying capacitor type inverter when the flying capacitor type inverter is started, so that the direct-current power supply, the third switch module, the third inverter bridge and the third flying capacitor form a fifth loop, and the direct-current power supply charges the third flying capacitor through the fifth loop;

when the third switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the third flying capacitor and for being connected between the negative electrode of the direct-current power supply and the second end of the third flying capacitor, the control module is used for controlling the third switch module when the flying capacitor type inverter is started, so that the direct-current power supply, the third switch module and the third flying capacitor form a sixth loop, and the direct-current power supply charges the third flying capacitor through the sixth loop;

the control module is further configured to control the third switching module to be turned off and control the third inverter bridge to start working when it is detected that the voltage across the third flying capacitor is not less than the first voltage; after the third switching module is switched off, the direct current power supply provides the first voltage to the third flying capacitor;

when the first switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the first flying capacitor, the second switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the second flying capacitor of the flying capacitor type inverter, and the third switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the third flying capacitor of the flying capacitor type inverter;

when the first switch module is used for being connected between the negative pole of the direct current power supply and the second end of the first flying capacitor, the second switch module is used for being connected between the negative pole of the direct current power supply and the second end of the second flying capacitor, and the third switch module is used for being connected between the negative pole of the direct current power supply and the second end of the third flying capacitor;

when the first switch module is used for being connected between the anode of the direct-current power supply and the first end of the first flying capacitor and is used for being connected between the cathode of the direct-current power supply and the second end of the first flying capacitor, the second switch module is used for being connected between the anode of the direct-current power supply and the first end of the second flying capacitor and is used for being connected between the cathode of the direct-current power supply and the second end of the second flying capacitor, and the third switch module is used for being connected between the anode of the direct-current power supply and the first end of the third flying capacitor and is used for being connected between the cathode of the direct-current power supply and the second end of the third flying capacitor.

5. The inverter control apparatus of claim 4, wherein the second switching module includes a fourth current limiting unit and a fourth switching unit, and the third switching module includes a fifth current limiting unit and a fifth switching unit; a second end of the fourth current limiting unit is connected with a first end of the fourth switching unit, and a second end of the fifth current limiting unit is connected with a first end of the fifth switching unit; the fourth switch unit and the fifth switch unit are controlled by the control module;

if the second switch module is connected between the positive electrode of the direct-current power supply and the first end of the second flying capacitor, the first end of the fourth current limiting unit is connected with the positive electrode of the direct-current power supply, and the second end of the fourth switch unit is connected with the first end of the second flying capacitor;

if the second switch module is connected between the negative electrode of the direct-current power supply and the second end of the second flying capacitor, the first end of the fourth current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the fourth switch unit is connected with the second end of the second flying capacitor;

the control module is further configured to control the fourth switching unit and a second inverter bridge of the flying capacitor inverter when the flying capacitor inverter is started, so that the dc power supply, the fourth switching unit, the fourth current limiting unit, the second inverter bridge and the second flying capacitor form the third loop, and the dc power supply charges the second flying capacitor through the third loop;

if the third switch module is connected between the positive electrode of the direct-current power supply and the first end of the third flying capacitor, the first end of the fifth current limiting unit is connected with the positive electrode of the direct-current power supply, and the second end of the fifth switch unit is connected with the first end of the third flying capacitor;

if the third switch module is connected between the negative electrode of the direct-current power supply and the second end of the third flying capacitor, the first end of the fifth current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the fifth switch unit is connected with the second end of the third flying capacitor;

the control module is further configured to control the fifth switching unit and a second inverter bridge of the flying capacitor inverter when the flying capacitor inverter is started, so that the dc power supply, the fifth switching unit, the fifth current limiting unit, the second inverter bridge, and the third flying capacitor form the fifth loop, and the dc power supply charges the third flying capacitor through the fifth loop.

6. The inverter control apparatus of claim 4, wherein the second switching module includes a sixth current limiting unit, a sixth switching unit, a seventh switching unit, and a seventh current limiting unit, and the third switching module includes an eighth current limiting unit, an eighth switching unit, a ninth switching unit, and a ninth current limiting unit; a second end of the sixth current limiting unit is connected with a first end of the sixth switching unit, and a second end of the eighth current limiting unit is connected with a first end of the eighth switching unit; a second end of the seventh current limiting unit is connected with a first end of the seventh switching unit, and a second end of the ninth current limiting unit is connected with a first end of the ninth switching unit; the sixth switch unit, the seventh switch unit, the eighth switch unit and the ninth switch unit are all controlled by the control module;

if the second switch module is connected between the positive electrode of the direct-current power supply and the first end of the second flying capacitor and between the negative electrode of the direct-current power supply and the second end of the second flying capacitor, the first end of the sixth current limiting unit is connected with the positive electrode of the direct-current power supply, the second end of the sixth switch unit is connected with the first end of the second flying capacitor, the first end of the seventh current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the seventh switch unit is connected with the second end of the second flying capacitor;

the control module is further configured to control the sixth switching unit and the seventh switching unit when the flying capacitor type inverter is started, so that the direct-current power supply, the sixth switching unit, the sixth current limiting unit, the second flying capacitor, the seventh switching unit and the seventh current limiting unit form the fourth loop, and the direct-current power supply charges the second flying capacitor through the fourth loop;

if the third switching module is connected between the positive electrode of the direct-current power supply and the first end of the third flying capacitor and between the negative electrode of the direct-current power supply and the second end of the third flying capacitor, the first end of the eighth current limiting unit is connected with the positive electrode of the direct-current power supply, the second end of the eighth switching unit is connected with the first end of the third flying capacitor, the first end of the ninth current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the ninth switching unit is connected with the second end of the third flying capacitor;

the control module is further configured to control the eighth switching unit and the ninth switching unit when the flying capacitor type inverter is started, so that the dc power supply, the eighth switching unit, the eighth current limiting unit, the third flying capacitor, the ninth switching unit and the ninth current limiting unit form the sixth loop, and the dc power supply charges the third flying capacitor through the sixth loop.

7. An inverter device comprising the inverter control apparatus according to any one of claims 1 to 6, the inverter device further comprising a first output terminal and a flying capacitor type inverter; the flying capacitor type inverter comprises a direct-current power supply, a first inverter bridge and a first flying capacitor; wherein the first inverter bridge is controlled by the control module; the first output end is used for outputting first phase electricity;

the positive pole of the direct current power supply is connected with the input positive pole of the first inverter bridge, the negative pole of the direct current power supply is connected with the input negative pole of the first inverter bridge, the midpoint of the direct current power supply is connected with the midpoint of an input bridge arm of the first inverter bridge, and the midpoint of the direct current power supply is used for providing zero potential; the first inverter bridge is controlled by a control module through a controlled end;

the first flying capacitor is connected to two ends of an output bridge arm of the first inverter bridge; the output end of the first inverter bridge is respectively connected with the first output end and the midpoint of the output bridge arm of the first inverter bridge.

8. The inverter device of claim 7, further comprising a second output terminal and a third output terminal; the flying capacitor type inverter further comprises a second inverter bridge, a third inverter bridge, a second flying capacitor and a third flying capacitor; the second output end is used for outputting second phase electricity, and the third output end is used for outputting third phase electricity;

the positive pole of the direct-current power supply is also respectively connected with the input positive pole of the second inverter bridge and the input positive pole of the third inverter bridge, the negative pole of the direct-current power supply is also respectively connected with the input negative pole of the second inverter bridge and the input negative pole of the third inverter bridge, and the midpoint of the direct-current power supply is also respectively connected with the midpoint of the input bridge arm of the second inverter bridge and the midpoint of the input bridge arm of the third inverter bridge; the second inverter bridge and the third inverter bridge are controlled by a control module through controlled ends;

the second flying capacitor is connected to two ends of an output bridge arm of the second inverter bridge; the output end of the second inverter bridge is respectively connected with the second output end and the midpoint of an output bridge arm of the second inverter bridge;

the third flying capacitor is connected to two ends of an output bridge arm of the third inverter bridge; and the output end of the third inverter bridge is respectively connected with the third output end and the midpoint of the output bridge arm of the third inverter bridge.

9. The inverter apparatus of claim 8, wherein the first inverter bridge comprises a first switching tube, a second switching tube, a third switching tube, a fourth switching tube, a fifth switching tube, a sixth switching tube, a seventh switching tube and an eighth switching tube;

the first end of the first switch tube is connected with the input anode of the first inverter bridge, the second end of the first switch tube is respectively connected with the first end of the second switch tube and the first end of the third switch tube, and the control end of the first switch tube is connected with the controlled end of the first inverter bridge;

a first end of the fourth switching tube is connected with a second end of the third switching tube and a first end of an output bridge arm of the first inverter bridge respectively, a second end of the fourth switching tube is connected with a first end of the eighth switching tube and an output end of the first inverter bridge respectively, and a control end of the fourth switching tube is connected with a controlled end of the first inverter bridge;

a first end of the fifth switching tube is connected with a second end of the second switching tube and the midpoint of the input bridge arm of the first inverter bridge respectively, a second end of the fifth switching tube is connected with a first end of the sixth switching tube and a second end of the seventh switching tube respectively, and a control end of the fifth switching tube is connected with a controlled end of the first inverter bridge;

a second end of the eighth switching tube is connected with a first end of the seventh switching tube and a second end of an output bridge arm of the first inverter bridge respectively, and a control end of the eighth switching tube is connected with a controlled end of the first inverter bridge;

a second end of the sixth switching tube is connected with the input cathode of the first inverter bridge, and a control end of the sixth switching tube is connected with the controlled end of the first inverter bridge;

the control end of the second switching tube, the control end of the third switching tube and the control end of the seventh switching tube are connected with the controlled end of the first inverter bridge;

the second inverter bridge and the third inverter bridge have the same structure as the first inverter bridge.

10. A control method applied to a control module in the inverter control apparatus according to any one of claims 1 to 6 and a control module in the inverter device according to any one of claims 8 or 9, the control method comprising:

at the start of the flying capacitor type inverter:

if the voltage at two ends of a first flying capacitor of the flying capacitor type inverter is smaller than a first voltage, controlling a first switch module to be switched from a disconnected state to a connected state;

and after the first switch module is in a conducting state, if the voltage at two ends of the first flying capacitor is not less than the first voltage, controlling the first switch module to be switched from the conducting state to a disconnecting state, and controlling a first inverter bridge of the flying capacitor type inverter to start working.

Technical Field

The invention belongs to the technical field of inverter control, and particularly relates to an inverter control device, inverter equipment and a control method.

Background

In a high-power supply system, the flying capacitor type inverter can solve the problems that the withstand voltage of a clamping diode in the diode clamping type inverter is unbalanced and the reverse voltage is difficult to recover quickly, meanwhile, each switching device can bear the same voltage, the output voltage and the output power of the inverter are improved, the inverter can directly supply power to a load in an alternating current mode, and the flying capacitor type inverter has wide application prospect.

The flying capacitor type inverter usually works under the working condition that the input is 1500Vdc, when the flying capacitor type inverter starts to work, part of switching devices of an inverter bridge bear all the voltage of a power supply, and therefore the problems of difficulty in model selection and high cost exist when the part of switching devices are in model selection.

Disclosure of Invention

In view of this, embodiments of the present invention provide a control circuit, an inverter device, and a control method for a three-phase converter, so as to solve the problems in the prior art that when a flying capacitor type inverter is started to operate, part of switching devices of an inverter bridge may bear all voltages of a power supply, so that when the part of switching devices is selected, the type selection is difficult and the cost is high.

A first aspect of an embodiment of the present invention provides an inverter control device, configured to control starting of a flying capacitor-type inverter, including a first switch module and a control module; the first switch module is controlled by the control module;

the first switch module is used for being connected between the positive pole of a direct-current power supply of the flying capacitor type inverter and the first end of a first flying capacitor of the flying capacitor type inverter, and/or is used for being connected between the negative pole of the direct-current power supply and the second end of the first flying capacitor;

when the first switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the first flying capacitor or between the negative electrode of the direct-current power supply and the second end of the first flying capacitor, the control module is used for controlling the first switch module and the first inverter bridge of the flying capacitor type inverter when the flying capacitor type inverter is started, so that the direct-current power supply, the first switch module, the first inverter bridge and the first flying capacitor form a first loop, and the direct-current power supply charges the first flying capacitor through the first loop;

when the first switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the first flying capacitor and between the negative electrode of the direct-current power supply and the second end of the first flying capacitor, the control module is used for controlling the first switch module when the flying capacitor type inverter is started, so that the direct-current power supply, the first switch module and the first flying capacitor form a second loop, and the direct-current power supply charges the first flying capacitor through the second loop;

the control module is further used for controlling the first switch module to be switched off and controlling the first inverter bridge to start working when the voltage at two ends of the first flying capacitor is detected to be not less than the first voltage; after the first switch module is switched off, the direct current power supply provides a first voltage to the first flying capacitor.

A second aspect of embodiments of the present invention provides an inverter apparatus, including the inverter control device according to the first aspect, the inverter apparatus further including a first output terminal and a flying capacitor-type inverter; the flying capacitor type inverter comprises a direct-current power supply, a first inverter bridge and a first flying capacitor; wherein, the first inverter bridge is controlled by the control module; the first output end is used for outputting first phase electricity;

the positive pole of the direct-current power supply is connected with the positive input pole of the first inverter bridge, the negative pole of the direct-current power supply is connected with the negative input pole of the first inverter bridge, the midpoint of the direct-current power supply is connected with the midpoint of an input bridge arm of the first inverter bridge, and the midpoint of the direct-current power supply is used for providing zero potential; the first inverter bridge is controlled by the control module through the controlled end;

the first flying capacitor is connected to two ends of an output bridge arm of the first inverter bridge; the output end of the first inverter bridge is respectively connected with the first output end and the midpoint of the output bridge arm of the first inverter bridge.

A third aspect of embodiments of the present invention provides a control method applied to a control module in an inverter control apparatus according to the first aspect as described above and a control module in an inverter device according to the second aspect as described above, the control method including:

at the start of the flying capacitor type inverter:

if the voltage at two ends of a first flying capacitor of the flying capacitor type inverter is smaller than the first voltage, controlling the first switch module to be switched from a disconnected state to a connected state;

after the first switch module is in a conducting state, if the voltage at two ends of the first flying capacitor is not less than the first voltage, the first switch module is controlled to be switched from the conducting state to a disconnecting state, and the first inverter bridge of the flying capacitor type inverter is controlled to start working.

Compared with the prior art, the embodiment of the invention has the following beneficial effects:

the inverter control device comprises a first switch module and a control module; the first switch module is controlled by the control module; when the first switch module and the flying capacitor type inverter adopt different connection modes, the direct-current power supply can pre-charge the first flying capacitor through different charging loops when the flying capacitor type inverter is started; such as: the direct-current power supply, the first switch module, the first inverter bridge and the first flying capacitor form a first loop by controlling the first switch module and the first inverter bridge of the flying capacitor type inverter, and the direct-current power supply charges the first flying capacitor through the first loop or controls the first switch module to form a second loop by controlling the direct-current power supply, the first switch module and the first flying capacitor, and the direct-current power supply charges the first flying capacitor through the second loop; after the first flying capacitor is precharged, the first inverter bridge is started to work, so that the withstand voltage requirement of the flying capacitor type inverter on a switching device of the first inverter bridge during starting can be reduced, the low-withstand-voltage switching device has better working characteristics and lower loss, and the working efficiency of the inverter is further improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of a flying capacitor-type inverter according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of an inverter control device according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of another inverter control device provided in the embodiment of the present invention;

fig. 4 is a schematic structural diagram of another inverter control device according to an embodiment of the present invention;

fig. 5 is a schematic circuit diagram of an inverter control device according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a fourth inverter control device according to an embodiment of the present invention;

fig. 7 is a schematic circuit structure diagram of an inverter device according to an embodiment of the present invention.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

In order to explain the technical means of the present invention, the following description will be given by way of specific examples.

Referring to fig. 1, a schematic structural diagram of a flying capacitor type inverter according to an embodiment of the present invention is shown. As shown in fig. 1, the flying capacitor inverter includes a dc power supply, an inverter bridge, and a flying capacitor CF, and the inverter bridge includes switching tubes Q1 to Q8.

When the flying capacitor type inverter works normally, the direct current power supply outputs alternating current through the inverter bridge. When the flying capacitor type inverter is started, the flying capacitor CF is not charged yet, which is equivalent to a lead, and the voltage of the dc power supply is directly applied to a part of the switching tubes of the inverter bridge (such as the switching tube Q3 or the switching tube Q7). Generally, the voltage of the direct-current power supply is not less than 1500Vdc, the voltage withstanding value of the switching tube is required to be high, the higher the voltage withstanding value of the switching tube is, the more difficult the model selection is, the higher the internal resistance is, and the working efficiency of the flying capacitor type inverter is affected.

The embodiment of the invention provides an inverter control device, which is used for controlling a flying capacitor type inverter to work and comprises a first switch module and a control module; the first switch module is controlled by the control module;

the first switch module is used for being connected between the positive pole of a direct-current power supply of the flying capacitor type inverter and the first end of a first flying capacitor of the flying capacitor type inverter, and/or is used for being connected between the negative pole of the direct-current power supply and the second end of the first flying capacitor;

when the first switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the first flying capacitor or between the negative electrode of the direct-current power supply and the second end of the first flying capacitor, the control module is used for controlling the first switch module and the first inverter bridge of the flying capacitor type inverter when the flying capacitor type inverter is started, so that the direct-current power supply, the first switch module, the first inverter bridge and the first flying capacitor form a first loop, and the direct-current power supply charges the first flying capacitor through the first loop;

for example, refer to fig. 2, which shows a schematic structural diagram of an inverter control device according to an embodiment of the present invention. As shown in fig. 2, the first switching module 101 is configured to be connected between a positive electrode of a dc power supply 201 and a first end of a first flying capacitor 202, the positive electrode of the dc power supply 201 is further connected to an input positive electrode of a first inverter bridge 203, and a negative electrode of the dc power supply 201 is connected to an input negative electrode of the first inverter bridge 203. At this time, the control module 102 is configured to control the first switch module 101 and the first inverter bridge 203 when the flying capacitor type inverter 20 is started, so that the dc power supply 201, the first switch module 101, the first inverter bridge 203, and the first flying capacitor 202 form a first loop, and the dc power supply 201 charges the first flying capacitor 202 through the first loop. At this time, the first loop may be expressed as:

the positive pole of the direct current power supply 201, the first switching module 101, the first flying capacitor 202, the first inverter bridge 203 and the negative pole of the direct current power supply 201.

Referring to fig. 3, a schematic structural diagram of another inverter control device provided in the embodiment of the present invention is shown. As shown in fig. 3, the first switching module 101 is configured to be connected between a negative electrode of the dc power supply 201 and a second end of the first flying capacitor 202, where a positive electrode of the dc power supply 201 is connected to an input positive electrode of the first inverter bridge 203, and a negative electrode of the dc power supply 201 is further connected to an input negative electrode of the first inverter bridge 203. At this time, the control module 102 is configured to control the first switch module 101 and the first inverter bridge 203 when the flying capacitor type inverter 20 is started, so that the dc power supply 201, the first switch module 101, the first inverter bridge 203, and the first flying capacitor 202 form a first loop, and the dc power supply 201 charges the first flying capacitor 202 through the first loop. At this time, the first loop may be expressed as:

the positive pole of the direct current power supply 201, the first inverter bridge 203, the first flying capacitor 202, the first switch module 101 and the negative pole of the direct current power supply 201.

When the first switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the first flying capacitor and between the negative electrode of the direct-current power supply and the second end of the first flying capacitor, the control module is used for controlling the first switch module when the flying capacitor type inverter is started, so that the direct-current power supply, the first switch module and the first flying capacitor form a second loop, and the direct-current power supply charges the first flying capacitor through the second loop;

for example, referring to fig. 4, a schematic structural diagram of another inverter control device provided by an embodiment of the present invention is shown. As shown in fig. 4, the first switch module 101 is configured to be connected between an anode of the dc power supply 201 and a first end of the first flying capacitor 202, and to be connected between a cathode of the dc power supply 201 and a second end of the first flying capacitor 202, the anode of the dc power supply 201 is further configured to be connected to an input anode of the first inverter bridge 203, and the cathode of the dc power supply 201 is further configured to be connected to an input cathode of the first inverter bridge 203. At this time, the control module is configured to control the first switch module 101 when the flying capacitor type inverter is started, so that the dc power supply 201, the first switch module 101, and the first flying capacitor 202 form a second loop, and the dc power supply 201 charges the first flying capacitor through the second loop. At this time, the second loop can be expressed as:

the positive pole of the dc power supply 201-the first switch module 101-the first flying capacitor 202-the first switch module 101-the negative pole of the dc power supply 201.

The control module is further used for controlling the first switch module to be switched off and controlling the first inverter bridge to start working when the voltage at two ends of the first flying capacitor is detected to be not less than the first voltage; after the first switch module is switched off, the direct current power supply provides a first voltage to the first flying capacitor.

Optionally, the control module 102 may be a micro control unit (mcu).

For example, referring to fig. 5, a schematic circuit diagram of an inverter control device according to an embodiment of the present invention is shown. As shown in FIG. 5, the first inverter bridge may include switching transistors Q1-Q8, all of which are controlled by the control module. The first switching module may include a first current limiting unit R1, a first switching unit K1, a second current limiting unit R2, and a second switching unit K2, and the first switching unit K1 and the second switching unit K2 are controlled by the control module.

Specifically, when the flying capacitor type inverter is started, the control module controls the first switch unit K1 and the second switch unit K2 to be closed, and the direct-current power supply precharges the first flying capacitor. After the voltage at two ends of the first flying capacitor reaches the first voltage, the control module controls the first switch unit K1 and the second switch unit K2 to be disconnected, and controls the switch tubes Q1-Q8 to work normally.

According to the embodiment of the invention, the auxiliary loop (the first loop or the second loop) is added to pre-charge the first flying capacitor of the flying capacitor type inverter, so that the slow start of the flying capacitor type inverter is realized, the pressure bearing of part of switch tubes of a first inverter bridge in the flying capacitor type inverter can be reduced, when the flying capacitor type inverter is selected, the switch tubes with lower pressure resistance values can be selected, and the switch tubes with lower pressure resistance values have lower loss.

In some embodiments of the present invention, the first switching module includes a first current limiting unit and a first switching unit; the second end of the first current limiting unit is connected with the first end of the first switch unit; the first switch unit is controlled by the control module;

if the first switch module is connected between the anode of the direct-current power supply of the flying capacitor type inverter and the first end of the first flying capacitor of the flying capacitor type inverter, the first end of the first current limiting unit is connected with the anode of the direct-current power supply, and the second end of the first switch unit is connected with the first end of the first flying capacitor;

if the first switch module is connected between the negative electrode of the direct-current power supply and the second end of the first flying capacitor, the first end of the first current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the first switch unit is connected with the second end of the first flying capacitor;

the control module is further used for controlling the first switch unit and the first inverter bridge when the flying capacitor type inverter is started, so that the direct-current power supply, the first switch unit, the first current limiting unit, the first inverter bridge and the first flying capacitor form a first loop, and the direct-current power supply charges the first flying capacitor through the first loop.

Optionally, first current-limiting unit is used for playing the protection current-limiting effect when slowly starting for first flying capacitor charges, can improve the reliability of flying capacitor type dc-to-ac converter work, and first current-limiting unit and first switching power supply series connection, the position of the two can be interchanged, does not influence the slow start of charging of first flying capacitor, promptly: the first end of the first current limiting unit is connected with the second end of the unit of the first switch.

Exemplarily, the slow start of charging of the first flying capacitor is described as an example, after the control module controls the first switch unit to be closed, part of the switch tubes in the first inverter bridge may be correspondingly controlled to be turned on, so as to realize the slow start of charging of the first flying capacitor, where the slow start circuit of charging is as follows:

when the first switch module is respectively connected to the positive electrode of the dc power supply and the first end of the first flying capacitor, the first loop may be represented as:

the method comprises the following steps that (1) the positive pole of a direct-current power supply, a first current limiting unit, a first switching unit, a first flying capacitor, a first inverter bridge and the negative pole of the direct-current power supply are connected; or, the anode of the direct current power supply, the first switching unit, the first current limiting unit, the first flying capacitor, the first inverter bridge and the cathode of the direct current power supply.

When the first switch module is respectively connected to the negative electrode of the dc power supply and the second end of the first flying capacitor, the first loop may be represented as:

the method comprises the steps of A, generating a first flying capacitor, a first inverter bridge, a first switch unit, a first current limiting unit and a negative electrode of a direct-current power supply; or, the positive pole of the direct current power supply, the first flying capacitor, the first inverter bridge, the first current limiting unit, the first switching unit and the negative pole of the direct current power supply.

In some embodiments of the present invention, the first switching module includes a second current limiting unit, a second switching unit, a third switching unit, and a third current limiting unit; the second end of the second current limiting unit is connected with the first end of the second switch unit; the second end of the third current limiting unit is connected with the first end of the third switching unit; the second switch unit and the third switch unit are controlled by the control module;

if the first switch module is connected between the positive pole of the direct-current power supply and the first end of the first flying capacitor and between the negative pole of the direct-current power supply and the second end of the first flying capacitor, the first end of the second current limiting unit is connected with the positive pole of the direct-current power supply, the second end of the second switch unit is connected with the first end of the first flying capacitor, the first end of the third current limiting unit is connected with the negative pole of the direct-current power supply, and the second end of the third switch unit is connected with the second end of the first flying capacitor;

the control module is further used for controlling the second switch unit and the third switch unit when the flying capacitor type inverter is started, so that the direct-current power supply, the second switch unit, the second current limiting unit, the first flying capacitor, the third switch unit and the third current limiting unit form a second loop, and the direct-current power supply charges the first flying capacitor through the second loop.

For example, taking the slow start of charging the first flying capacitor as an example, after the control module controls the second switch unit and the third switch unit to be closed, the first flying capacitor charging slow start circuit, that is, the second loop, is:

the device comprises a positive electrode of a direct current power supply, a second current limiting unit, a second switching unit, a first flying capacitor, a third switching unit, a third current limiting unit and a negative electrode of the direct current power supply; the positions of the second current limiting unit and the second switch unit can be interchanged, the positions of the third switch unit and the third current limiting unit can be interchanged, and the interchange does not affect the charging slow start of the first flying capacitor.

The inverter control device provided by the embodiment of the invention can realize the charging slow start of each phase of flying capacitor, has various slow start modes, can select a proper charging slow start circuit design for each phase of flying capacitor according to design requirements or other conditions in actual application, greatly reduces the difficulty of circuit design and improves the efficiency and the flexibility of circuit design due to the design of various charging slow start circuits.

In some embodiments of the invention, the apparatus further comprises a second switching module and a third switching module; the second switch module and the third switch module are controlled by the control module;

the second switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of a second flying capacitor of the flying capacitor type inverter, and/or is used for being connected between the negative electrode of the direct-current power supply and the second end of the second flying capacitor;

when the second switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the second flying capacitor, or is used for being connected between the negative electrode of the direct-current power supply and the second end of the second flying capacitor, the control module is used for controlling the second switch module and the second inverter bridge of the flying capacitor type inverter when the flying capacitor type inverter is started, so that the direct-current power supply, the second switch module, the second inverter bridge and the second flying capacitor form a third loop, and the direct-current power supply charges the second flying capacitor through the third loop;

for example, referring to fig. 6, a schematic structural diagram of a fourth inverter control device provided in the embodiment of the present invention is shown. As shown in fig. 6, the second switching module 103 is configured to be connected between the positive electrode of the dc power supply 201 and the first end of the second flying capacitor 202, the positive electrode of the dc power supply 201 is further connected to the input positive electrode of the second inverter bridge 205, and the negative electrode of the dc power supply 201 is connected to the input negative electrode of the second inverter bridge 205. At this time, the control module 102 is configured to control the second switch module 103 and the second inverter bridge 205 when the flying capacitor type inverter is started, so that the dc power supply 201, the second switch module 103, the second inverter bridge 205, and the second flying capacitor 204 form a third loop, and the dc power supply 201 charges the second flying capacitor 204 through the third loop. At this time, the third loop can be expressed as:

the positive pole of the direct current power supply 201, the second switch module 103, the second flying capacitor 204, the second inverter bridge 205, and the negative pole of the direct current power supply 201.

When the second switching module 103 is used to connect between the negative terminal of the dc power supply 201 and the second terminal of the second flying capacitor 204, the third loop can be expressed as:

the positive pole of the direct current power supply 201, the second inverter bridge 205, the second flying capacitor 204, the second switch module 103 and the negative pole of the direct current power supply 201.

When the second switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the second flying capacitor and between the negative electrode of the direct-current power supply and the second end of the second flying capacitor, the control module is used for controlling the second switch module when the flying capacitor type inverter is started, so that the direct-current power supply, the second switch module and the second flying capacitor form a fourth loop, and the direct-current power supply charges the second flying capacitor through the fourth loop;

illustratively, the second switch module is configured to be connected between the positive electrode of the dc power supply and the first end of the second flying capacitor, and is configured to be connected between the negative electrode of the dc power supply and the second end of the second flying capacitor, the positive electrode of the dc power supply 201 is further configured to be connected to the input positive electrode of the second inverter bridge 205, and the negative electrode of the dc power supply 201 is further configured to be connected to the input negative electrode of the second inverter bridge 205. At this time, the control module 102 is configured to control the second switch module 103 when the flying capacitor type inverter is started, so that the dc power supply 201, the second switch module 103, and the second flying capacitor 204 form a fourth loop, and the dc power supply 201 charges the second flying capacitor through the fourth loop; at this time, the fourth loop can be expressed as:

the positive pole of the direct current power supply 201, the second flying capacitor 204 of the second switch module 103, and the negative pole of the direct current power supply 201.

The control module is further used for controlling the second switch module to be switched off and controlling the second inverter bridge to start working when the voltage at two ends of the second flying capacitor is detected to be not less than the first voltage; after the second switch module is switched off, the direct current power supply provides a first voltage for the second flying capacitor;

the third switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of a third flying capacitor of the flying capacitor type inverter, and/or is used for being connected between the negative electrode of the direct-current power supply and the second end of the third flying capacitor;

when the third switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the third flying capacitor, or is used for being connected between the negative electrode of the direct-current power supply and the second end of the third flying capacitor, the control module is used for controlling the third switch module and the third inverter bridge of the flying capacitor type inverter when the flying capacitor type inverter is started, so that the direct-current power supply, the third switch module, the third inverter bridge and the third flying capacitor form a fifth loop, and the direct-current power supply charges the third flying capacitor through the fifth loop;

illustratively, the third switching module 104 is configured to be connected between the positive terminal of the dc power supply 201 and the first terminal of the third flying capacitor 206, where the fifth loop may be represented as:

the positive pole of the direct current power supply 201, the third switching module 104, the third flying capacitor 206, the third inverter bridge 207 and the negative pole of the direct current power supply 201.

The third switching module 104 is configured to be connected between the negative terminal of the dc power supply 201 and the second terminal of the third flying capacitor 204, and the fifth loop may be represented as:

the positive pole of the direct current power supply 201, the third inverter bridge 207, the third flying capacitor 206, the third switch module 104 and the negative pole of the direct current power supply 201.

When the third switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the third flying capacitor and between the negative electrode of the direct-current power supply and the second end of the third flying capacitor, the control module is used for controlling the third switch module when the flying capacitor type inverter is started, so that the direct-current power supply, the third switch module and the third flying capacitor form a sixth loop, and the direct-current power supply charges the third flying capacitor through the sixth loop;

illustratively, the third switching module is configured to be connected between the positive terminal of the dc power supply and the first terminal of the third flying capacitor, and is configured to be connected between the negative terminal of the dc power supply and the second terminal of the third flying capacitor, where the sixth loop may be represented as:

the positive pole of the direct current power supply 201, the third switching module 104, the third flying capacitor 206, the third switching module 104 and the negative pole of the direct current power supply 201.

The control module is further used for controlling the third switch module to be switched off and controlling the third inverter bridge to start working when the voltage at the two ends of the third flying capacitor is detected to be not less than the first voltage; after the third switch module is switched off, the direct current power supply provides a first voltage for the third flying capacitor;

when the first switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the first flying capacitor, the second switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the second flying capacitor of the flying capacitor type inverter, and the third switch module is used for being connected between the positive electrode of the direct-current power supply and the first end of the third flying capacitor of the flying capacitor type inverter;

when the first switch module is used for being connected between the negative electrode of the direct-current power supply and the second end of the first flying capacitor, the second switch module is used for being connected between the negative electrode of the direct-current power supply and the second end of the second flying capacitor, and the third switch module is used for being connected between the negative electrode of the direct-current power supply and the second end of the third flying capacitor;

when the first switch module is used for being connected between the anode of the direct-current power supply and the first end of the first flying capacitor and used for being connected between the cathode of the direct-current power supply and the second end of the first flying capacitor, the second switch module is used for being connected between the anode of the direct-current power supply and the first end of the second flying capacitor and used for being connected between the cathode of the direct-current power supply and the second end of the second flying capacitor, and the third switch module is used for being connected between the anode of the direct-current power supply and the first end of the third flying capacitor and used for being connected between the cathode of the direct-current power supply and the second end of the third flying capacitor.

Optionally, the connection forms of the first switch module, the second switch module, and the third switch module and the flying capacitor type inverter may be the same, for example, each switch module is connected between the negative electrode of the dc power supply and the second end of the corresponding flying capacitor, or each switch module is connected between the positive electrode of the dc power supply and the first end of the corresponding flying capacitor, or each switch module is used to be connected between the positive electrode of the dc power supply and the first end of the corresponding flying capacitor, and is used to be connected between the negative electrode of the dc power supply and the second end of the corresponding flying capacitor. The connection forms of the switch modules are consistent, so that the states of the switch modules can be controlled through similar logics, the switch tubes of the flying capacitor type inverter can be controlled, and the implementation difficulty of the control logics is greatly reduced. The connection form of each switch module and the flying capacitor type inverter can be different, and a proper connection form can be selected according to actual needs.

According to the embodiment of the invention, the auxiliary loop (the third loop, the fourth loop, the fifth loop or the sixth loop) is added to pre-charge the second flying capacitor and the third flying capacitor of the flying capacitor type inverter, so that the slow start of the flying capacitor type inverter is realized, the pressure bearing of partial switch tubes of the second inverter bridge and the third inverter bridge in the flying capacitor type inverter can be reduced, and the switch tube with a lower pressure resistance value can be selected during model selection, so that the loss of the switch tube with the lower pressure resistance value is lower, and by adopting the mode, the cost is reduced and the efficiency is improved under the condition that the normal work of the flying capacitor type inverter is not influenced.

In some embodiments of the present invention, the second switching module includes a fourth current limiting unit and a fourth switching unit, and the third switching module includes a fifth current limiting unit and a fifth switching unit; the second end of the fourth current limiting unit is connected with the first end of the fourth switching unit, and the second end of the fifth current limiting unit is connected with the first end of the fifth switching unit; the fourth switch unit and the fifth switch unit are controlled by the control module;

if the second switch module is connected between the positive electrode of the direct-current power supply and the first end of the second flying capacitor, the first end of the fourth current limiting unit is connected with the positive electrode of the direct-current power supply, and the second end of the fourth switch unit is connected with the first end of the second flying capacitor;

if the second switch module is connected between the negative electrode of the direct-current power supply and the second end of the second flying capacitor, the first end of the fourth current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the fourth switch unit is connected with the second end of the second flying capacitor;

the control module is further used for controlling the fourth switching unit and the second inverter bridge of the flying capacitor type inverter when the flying capacitor type inverter is started, so that the direct-current power supply, the fourth switching unit, the fourth current limiting unit, the second inverter bridge and the second flying capacitor form a third loop, and the direct-current power supply charges the second flying capacitor through the third loop;

illustratively, the second switching module is connected between the positive terminal of the dc power supply and the first terminal of the second flying capacitor, and the third loop may be represented as:

the positive pole of the direct-current power supply, the second switching unit, the second current-limiting unit, the second flying capacitor, the second inverter bridge and the negative pole of the direct-current power supply; or the positive pole of the direct current power supply, the second current limiting unit, the second switching unit, the second flying capacitor, the second inverter bridge and the negative pole of the direct current power supply.

The second switch module is connected between the negative electrode of the dc power supply and the second end of the second flying capacitor, and the third loop can be represented as:

the positive pole of the direct-current power supply, the second flying capacitor, the second inverter bridge, the second switching unit, the second current limiting unit and the negative pole of the direct-current power supply; or the positive pole of the direct current power supply, the second flying capacitor, the second inverter bridge, the second current limiting unit, the second switching unit and the negative pole of the direct current power supply.

If the third switch module is connected between the positive electrode of the direct-current power supply and the first end of the third flying capacitor, the first end of the fifth current limiting unit is connected with the positive electrode of the direct-current power supply, and the second end of the fifth switch unit is connected with the first end of the third flying capacitor;

if the third switch module is connected between the negative electrode of the direct-current power supply and the second end of the third flying capacitor, the first end of the fifth current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the fifth switch unit is connected with the second end of the third flying capacitor;

the control module is further used for controlling the fifth switching unit and the second inverter bridge of the flying capacitor type inverter when the flying capacitor type inverter is started, so that the direct-current power supply, the fifth switching unit, the fifth current limiting unit, the second inverter bridge and the third flying capacitor form a fifth loop, and the direct-current power supply charges the third flying capacitor through the fifth loop.

Illustratively, the third switching module is connected between the positive electrode of the dc power supply and the first end of the third flying capacitor, and the fifth loop may be represented as:

the positive pole of the direct-current power supply, the fifth switching unit, the fifth current-limiting unit, the third flying capacitor, the third inverter bridge and the negative pole of the direct-current power supply; or, the positive pole of the direct current power supply, the fifth current limiting unit, the fifth switching unit, the third flying capacitor, the third inverter bridge and the negative pole of the direct current power supply.

The third switching module is connected between the negative electrode of the dc power supply and the second terminal of the third flying capacitor, and the fifth loop may be represented as:

the positive pole of the direct-current power supply, the third flying capacitor, the third inverter bridge, the fifth switching unit, the fifth current limiting unit and the negative pole of the direct-current power supply; or, the positive pole of the direct current power supply, the third flying capacitor, the third inverter bridge, the fifth current limiting unit, the fifth switching unit and the negative pole of the direct current power supply.

In some embodiments of the present invention, the second switching module includes a sixth current limiting unit, a sixth switching unit, a seventh switching unit, and a seventh current limiting unit, and the third switching module includes an eighth current limiting unit, an eighth switching unit, a ninth switching unit, and a ninth current limiting unit; the second end of the sixth current limiting unit is connected with the first end of the sixth switching unit, and the second end of the eighth current limiting unit is connected with the first end of the eighth switching unit; the second end of the seventh current limiting unit is connected with the first end of the seventh switching unit, and the second end of the ninth current limiting unit is connected with the first end of the ninth switching unit; the sixth switch unit, the seventh switch unit, the eighth switch unit and the ninth switch unit are all controlled by the control module;

if the second switch module is connected between the positive electrode of the direct-current power supply and the first end of the second flying capacitor and between the negative electrode of the direct-current power supply and the second end of the second flying capacitor, the first end of the sixth current limiting unit is connected with the positive electrode of the direct-current power supply, the second end of the sixth switch unit is connected with the first end of the second flying capacitor, the first end of the seventh current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the seventh switch unit is connected with the second end of the second flying capacitor;

the control module is further used for controlling the sixth switching unit and the seventh switching unit when the flying capacitor type inverter is started, so that the direct-current power supply, the sixth switching unit, the sixth current limiting unit, the second flying capacitor, the seventh switching unit and the seventh current limiting unit form a fourth loop, and the direct-current power supply charges the second flying capacitor through the fourth loop;

illustratively, the second switch module is connected between the positive terminal of the dc power supply and the first terminal of the second flying capacitor, and between the negative terminal of the dc power supply and the second terminal of the second flying capacitor, and the fourth loop may be represented as:

the positive pole of the direct current power supply, the sixth switching unit, the sixth current limiting unit, the second flying capacitor, the seventh switching unit, the seventh current limiting unit and the negative pole of the direct current power supply; the positions of the sixth switching unit and the sixth current limiting unit can be interchanged, and the positions of the seventh switching unit and the seventh current limiting unit can be interchanged.

If the third switch module is connected between the positive electrode of the direct-current power supply and the first end of the third flying capacitor and between the negative electrode of the direct-current power supply and the second end of the third flying capacitor, the first end of the eighth current limiting unit is connected with the positive electrode of the direct-current power supply, the second end of the eighth switch unit is connected with the first end of the third flying capacitor, the first end of the ninth current limiting unit is connected with the negative electrode of the direct-current power supply, and the second end of the ninth switch unit is connected with the second end of the third flying capacitor;

the control module is further used for controlling the eighth switching unit and the ninth switching unit when the flying capacitor type inverter is started, so that the direct-current power supply, the eighth switching unit, the eighth current limiting unit, the third flying capacitor, the ninth switching unit and the ninth current limiting unit form a sixth loop, and the direct-current power supply charges the third flying capacitor through the sixth loop.

Illustratively, the third switching module is connected between the positive terminal of the dc power supply and the first terminal of the third flying capacitor, and between the negative terminal of the dc power supply and the second terminal of the third flying capacitor, where the sixth loop may be represented as:

the positive electrode of the direct current power supply, the eighth switching unit, the eighth current limiting unit, the third flying capacitor, the ninth switching unit, the ninth current limiting unit and the negative electrode of the direct current power supply; the positions of the eighth switching unit and the eighth current limiting unit can be interchanged, and the positions of the ninth switching unit and the ninth current limiting unit can be interchanged.

Referring to fig. 7, a schematic circuit diagram of an inverter device according to an embodiment of the present invention is shown. As shown in fig. 7, an inverter device includes the inverter control apparatus according to the above embodiment, and further includes a first output terminal a and a flying capacitor type inverter; the flying capacitor type inverter includes a direct current power supply 201, a first inverter bridge 203, and a first flying capacitor 202; wherein, the first inverter bridge 203 is controlled by the control module; the first output end A is used for outputting first phase electricity;

a positive electrode of the direct current power supply 201 is connected with an input positive electrode of the first inverter bridge 203, a negative electrode of the direct current power supply is connected with an input negative electrode of the first inverter bridge 203, a middle point of the direct current power supply 201 is connected with a middle point of an input bridge arm of the first inverter bridge 203, and the middle point of the direct current power supply 201 is used for providing zero potential; wherein, the first inverter bridge 203 is controlled by the control module through the controlled end;

the first flying capacitor 202 is connected to two ends of an output bridge arm of the first inverter bridge 203; the output end of the first inverter bridge 203 is connected to the first output end a and the midpoint of the output bridge arm of the first inverter bridge 203.

In some embodiments of the present invention, referring to fig. 7, the inverter device further includes a second output terminal B and a third output terminal C; the flying capacitor type inverter further comprises a second inverter bridge 205, a third inverter bridge 207, a second flying capacitor 204 and a third flying capacitor 206; the second output end B is used for outputting second phase electricity, and the third output end C is used for outputting third phase electricity;

a direct current power supply 201, the positive pole of which is also connected with the input positive pole of the second inverter bridge 205 and the input positive pole of the third inverter bridge 207 respectively, the negative pole of which is also connected with the input negative pole of the second inverter bridge 205 and the input negative pole of the third inverter bridge 207 respectively, and the middle point of which is also connected with the middle point of the input bridge arm of the second inverter bridge 205 and the middle point of the input bridge arm of the third inverter bridge 207 respectively; wherein, the second inverter bridge 205 and the third inverter bridge 207 are controlled by the control module through the controlled end;

the second flying capacitor 204 is connected to two ends of an output bridge arm of the second inverter bridge 205; the output end of the second inverter bridge 205 is connected to the second output end B and the midpoint of the output bridge arm of the second inverter bridge 205;

the third flying capacitor 206 is connected to both ends of the output bridge arm of the third inverter bridge 207; the output end of the third inverter bridge 207 is connected to the third output end C and the midpoint of the output bridge arm of the third inverter bridge 207, respectively.

In some embodiments of the present invention, referring to fig. 7, the first inverter bridge includes a first switching tube Q1, a second switching tube Q2, a third switching tube Q3, a fourth switching tube Q4, a fifth switching tube Q5, a sixth switching tube Q6, a seventh switching tube Q7, and an eighth switching tube Q8;

a first switch tube Q1, a first end of which is connected with the input anode of the first inverter bridge, a second end of which is connected with the first end of a second switch tube Q2 and the first end of a third switch tube Q3, respectively, and a control end of which is connected with the controlled end of the first inverter bridge 203;

a first end of a fourth switching tube Q4 is connected to the second end of the third switching tube Q3 and the first end of the output bridge arm of the first inverter bridge 203, a second end of the fourth switching tube Q4 is connected to the first end of the eighth switching tube Q8 and the output end of the first inverter bridge 203, and a control end of the fourth switching tube Q4 is connected to the controlled end of the first inverter bridge 203;

a fifth switching tube Q5, a first end of which is connected to the second end of the second switching tube Q2 and the midpoint of the input bridge arm of the first inverter bridge 203, a second end of which is connected to the first end of the sixth switching tube Q6 and the second end of the seventh switching tube Q7, respectively, and a control end of which is connected to the controlled end of the first inverter bridge 203;

a second end of the eighth switching tube Q8 is connected to the first end of the seventh switching tube Q7 and the second end of the output bridge arm of the first inverter bridge 203, respectively, and a control end is connected to the controlled end of the first inverter bridge 203;

a second end of the sixth switching tube Q6 is connected with the input cathode of the first inverter bridge 203, and a control end is connected with the controlled end of the first inverter bridge 203;

the control end of the second switching tube Q2, the control end of the third switching tube Q3 and the control end of the seventh switching tube Q7 are all connected with the controlled end of the first inverter bridge 203;

the second inverter bridge 205 and the third inverter bridge 207 have the same structure as the first inverter bridge 203.

Optionally, the dc power supply 201 may include a first supporting capacitor C1 and a second supporting capacitor C2 connected in series; the connection end of the first supporting capacitor C1 and the second supporting capacitor C2 is the midpoint of the dc power supply 201.

Optionally, in the first inverter bridge 203, a connection point between the second end of the second switching tube Q2 and the first end of the fifth switching tube Q5 is an input bridge arm midpoint of the first inverter bridge 203, and a connection point between the second end of the fourth switching tube Q4 and the first end of the eighth switching tube Q8 is an output bridge arm midpoint of the first inverter bridge 203;

in the second inverter bridge 205, a connection point between the second end of the second switching tube Q2 and the first end of the fifth switching tube Q5 is an input bridge arm midpoint of the second inverter bridge 205, and a connection point between the second end of the fourth switching tube Q4 and the first end of the eighth switching tube Q8 is an output bridge arm midpoint of the second inverter bridge 205;

in the third inverter bridge 207, a connection point between the second end of the second switching tube Q2 and the first end of the fifth switching tube Q5 is an input bridge arm midpoint of the third inverter bridge 207, and a connection point between the second end of the fourth switching tube Q4 and the first end of the eighth switching tube Q8 is an output bridge arm midpoint of the third inverter bridge 207.

Referring to fig. 7, in some embodiments of the present invention, the inverter device further includes a first filtering module, 301, a second filtering module 302, and a third filtering module 303; wherein the content of the first and second substances,

a first end of the first filtering module 301 is connected to the output end of the first inverter bridge 203, a second end of the first filtering module is connected to the first output end a, and a common end of the first filtering module 301 is connected to a common end of the second filtering module 302 and a common end of the third filtering module 303 respectively;

a second filtering module 302, a first end of which is connected to the output end of the second inverter bridge 205, and a second end of which is connected to the second output end B;

a first end of the third filtering module 303 is connected to the output end of the third inverter bridge 207, and a second end thereof is connected to the inverted third output end C.

Optionally, the common terminal of the first filtering module 301, the common terminal of the second filtering module 302, and the common terminal of the third filtering module 303 may also be all grounded.

Referring to fig. 7, in some embodiments of the present invention, the first filtering module 301 includes a filtering inductor L1 and a filtering capacitor CL 1;

a first end of the filter inductor L1 is connected to the first end of the first filter module 301, and a second end of the filter inductor L1 is connected to the first end of the filter capacitor CL1 and the second end of the first filter module 301, respectively;

a second end of the filter capacitor CL1 is connected to the common end of the first filter module 301;

the second filtering module 302 and the third filtering module 303 are both the same in structure as the first filtering module.

An embodiment of the present invention further provides a control method, which is applicable to a control module in the inverter control device and a control module in the inverter device provided in the above embodiment, and the control method includes:

at the start of the flying capacitor type inverter:

if the voltage at two ends of a first flying capacitor of the flying capacitor type inverter is smaller than the first voltage, controlling the first switch module to be switched from a disconnected state to a connected state;

after the first switch module is in a conducting state, if the voltage at two ends of the first flying capacitor is not less than the first voltage, the first switch module is controlled to be switched from the conducting state to a disconnecting state, and the first inverter bridge of the flying capacitor type inverter is controlled to start working.

The control method may further include:

if the voltage at two ends of a second flying capacitor of the flying capacitor type inverter is smaller than the first voltage, controlling the second switch module to be switched from a disconnected state to a connected state;

after the second switch module is in a conducting state, if the voltage at two ends of the second flying capacitor is not less than the first voltage, controlling the second switch module to be switched from the conducting state to a disconnecting state, and controlling a second inverter bridge of the flying capacitor type inverter to start working;

if the voltage at two ends of a third flying capacitor of the flying capacitor type inverter is smaller than the first voltage, controlling the third switch module to be switched from the off state to the on state;

and after the third switching module is in a conducting state, if the voltage at two ends of the third flying capacitor is not less than the first voltage, controlling the third switching module to be switched from the conducting state to a disconnecting state, and controlling a third inverter bridge of the flying capacitor type inverter to start working.

For example, referring to fig. 7, a starting process of the inverter device implemented by the present invention is described, taking the output of the first phase power as an example:

in the first case: the first switching module 101 includes a second switching unit K1, a third switching unit K2, a second current limiting unit R1, and a third current limiting unit R2, and at this time:

when the inverter equipment needs to be started, the control module controls the closing of K1 and K2, the first inverter bridge 203 does not work at the moment, the direct-current power supply 201 charges the first flying capacitor 202, when the voltage at the two ends of the first flying capacitor 202 is not smaller than the first voltage (the first voltage can be half of the voltage value of the direct-current power supply), the charging of the first flying capacitor is slowly started, the control module controls the disconnection of K1 and K2, and controls the normal work of the first inverter bridge 203 to output first-phase electricity.

The second switch module 103 may include a sixth switch unit K3, a seventh switch unit K4, a sixth current limiting unit R3, and a seventh current limiting unit R4, and the charging slow start process of the second flying capacitor 204 is the same as the charging slow start process of the first flying capacitor 202.

The third switching module 104 may include an eighth switching unit K5, a ninth switching unit K6, an eighth current limiting unit R5, and a ninth current limiting unit R6, and the charging slow start process of the third flying capacitor 206 is the same as the charging slow start process of the first flying capacitor 202.

In the second case, the first switching module 101 includes a first switching unit K1 and a first current limiting unit R1, and at this time:

when the inverter equipment needs to be started, the control module controls the switch K1 to be closed, and simultaneously controls the switch Q7 and the switch Q6 of the seventh switch tube and the first inverter bridge 203 to be closed, at this time, the direct-current power supply 201, the first switch module 103, the first flying capacitor 202 and the first inverter bridge 203 form a loop to charge the first flying capacitor 202, when the voltage at the two ends of the first flying capacitor 203 is not less than the first voltage, the charging and slow start of the first flying capacitor 202 is completed, the control module controls the switch K1 to be opened, and simultaneously controls the first inverter bridge 203 to normally work and output the first phase power.

The second switching module 103 may comprise a fourth switching unit K3 and a fourth current limiting unit R3, and the charging slow start process of the second flying capacitor 204 is the same as the charging slow start process of the first flying capacitor 202.

The third switching module 104 may comprise a fifth switching unit K5 and a fifth current limiting unit R5, and the charging slow start process of the third flying capacitor 206 is the same as the charging slow start process of the first flying capacitor 202.

In embodiments of the present invention, the above cases may be used in combination, for example, a first inverter bridge may output a first phase power in a first case, a second inverter bridge may output a second phase power in a second case, and so on. The above conditions can be combined for use, three-phase power output can also be realized by adopting the same condition, and the specific use can be combined with practical application.

By adopting the scheme provided by the embodiment of the invention, the first flying capacitor 202 is charged to the first voltage, then the first inverter bridge is started to output the first phase power, and at the moment, the third switching tube Q3 and the seventh switching tube Q7 only need to bear the voltage of the difference value between the direct-current power supply and the first voltage, and cannot directly bear the voltage value of the direct-current power supply. If the first voltage is 750Vdc, the third switch tube Q3 and the seventh switch tube Q7 only need to bear the voltage of 750Vdc, so that the voltage withstanding requirement of the switch tubes is reduced undoubtedly, the cost is reduced, and the switching tubes with low withstanding voltage have better performance, so that the conversion efficiency can be synchronously improved.

It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.

The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.