阅读说明：本技术 一种隔离式三相四线制逆变电源电路 (Isolated three-phase four-wire system inverter circuit ) 是由 范龙艳 于 2020-12-01 设计创作，主要内容包括：本发明提供一种隔离式三相四线制逆变电源电路,属于电源设备的技术领域,包括一个或多个隔离DCDC变换模块、三相四桥臂逆变模块及滤波模块,一个或多个隔离DCDC变换模块的输入端与外部电池电连接,一个或多个隔离DCDC变换模块的输出端与三相四桥臂逆变模块的输入端电连接,三相四桥臂逆变模块的输出端与滤波模块的输入端电连接,滤波模块的输出端与外部负载电连接。本发明具有保障用电设备的安全,且体积小、重量轻、便于车载安装的优点。(The invention provides an isolated three-phase four-wire system inverter power circuit, which belongs to the technical field of power equipment and comprises one or more isolated DCDC conversion modules, three-phase four-leg inverter modules and a filter module, wherein the input end of the one or more isolated DCDC conversion modules is electrically connected with an external battery, the output end of the one or more isolated DCDC conversion modules is electrically connected with the input end of the three-phase four-leg inverter modules, the output end of the three-phase four-leg inverter modules is electrically connected with the input end of the filter module, and the output end of the filter module is electrically connected with an external load. The invention has the advantages of ensuring the safety of electric equipment, small volume, light weight and convenient vehicle-mounted installation.)

1. The isolated three-phase four-wire system inverter power circuit is characterized by comprising one or more isolated DCDC conversion modules, a three-phase four-leg inverter module and a filtering module, wherein the input end of the one or more isolated DCDC conversion modules is electrically connected with an external battery, the output end of the one or more isolated DCDC conversion modules is electrically connected with the input end of the three-phase four-leg inverter module, the output end of the three-phase four-leg inverter module is electrically connected with the input end of the filtering module, and the output end of the filtering module is electrically connected with an external load.

2. The circuit of claim 1, wherein the isolated DCDC conversion module comprises two LLC full-bridge conversion units, input sides of the two LLC full-bridge conversion units both being electrically connected to an external battery, input sides of the two LLC full-bridge conversion units being connected in parallel, output sides of the two LLC full-bridge conversion units being connected in series.

3. The circuit of claim 2, wherein the LLC full-bridge conversion unit comprises a full-bridge circuit, an LC filter circuit, a resonant transformer T, and an output rectification circuit, an input terminal of the full-bridge circuit is electrically connected to an external battery, an output terminal of the full-bridge circuit is electrically connected to a primary side of the resonant transformer T, the LC filter circuit is connected in series between the full-bridge circuit and the resonant transformer T, a secondary side of the resonant transformer T is electrically connected to an input terminal of the output rectification circuit, and an output terminal of the output rectification current is electrically connected to the three-phase four-leg inverter module.

4. The circuit of claim 3, wherein the full bridge circuit comprises a first NMOS transistor Q1, a second NMOS transistor Q2, a third NMOS transistor Q3 and a fourth NMOS transistor Q4 which are connected in series in sequence, an external battery is electrically connected with a connection node of the first NMOS transistor Q1 and the second NMOS transistor Q2 and a connection node of the third NMOS transistor Q3 and the fourth NMOS transistor Q4, and a connection node of the first NMOS transistor Q1 and the third NMOS transistor Q3 and a connection node of the second NMOS transistor Q2 and the fourth NMOS transistor Q4 are electrically connected with the primary side of the resonant transformer T.

5. The circuit of claim 4, wherein the driving signal of the first NMOS transistor Q1 and the driving signal of the fourth NMOS transistor Q4 are in phase and the same, the driving signal of the second NMOS transistor Q2 and the driving signal of the third NMOS transistor Q3 are in phase and the same, the phase difference between the driving signal of the first NMOS transistor Q1 and the driving signal of the second NMOS transistor Q2 is 180 °, and the frequency and the duty cycle of the driving signal of the first NMOS transistor Q1 and the driving signal of the second NMOS transistor Q2 are the same.

6. The circuit of any one of claims 2-5, wherein the LLC full-bridge conversion unit further comprises an input filter capacitor C1, the input filter capacitor C1 being connected in parallel across the full-bridge circuit.

7. The circuit of any one of claims 2-5, wherein the LLC full bridge conversion unit further comprises an output filter capacitor C2, the output filter capacitor C2 being connected in parallel to the output rectification circuit.

8. The circuit according to any one of claims 1 to 5, wherein the three-phase four-leg inverter module comprises an N-phase leg, a U-phase leg, a V-phase leg and a W-phase leg which are connected in parallel, input ends of the N-phase leg, the U-phase leg, the V-phase leg and the W-phase leg are all electrically connected with output ends of the one or more isolated DCDC conversion modules, and output ends of the N-phase leg, the U-phase leg, the V-phase leg and the W-phase leg are all electrically connected with input ends of the filter module.

9. The circuit of claim 8, wherein the U-phase bridge arm, the V-phase bridge arm and the W-phase bridge arm are identical in structure, and the U-phase bridge arm comprises a first switch tube S1 and a second switch tube S2 which are connected in series.

10. The circuit of claim 8, wherein the filter module comprises an N-phase LC filter circuit, a U-phase LC filter circuit, a V-phase LC filter circuit and a W-phase LC filter circuit, an output end of the N-phase bridge arm is electrically connected with the N-phase LC filter circuit, an output end of the U-phase bridge arm is electrically connected with the U-phase LC filter circuit, an output end of the V-phase bridge arm is electrically connected with the V-phase LC filter circuit, the W-phase bridge arm is electrically connected with the W-phase LC filter circuit, and output ends of the N-phase LC filter circuit, the U-phase LC filter circuit, the V-phase LC filter circuit and the W-phase LC filter circuit are electrically connected with an external load.

Technical Field

The invention relates to the technical field of power supply equipment, in particular to an isolated three-phase four-wire system inverter power supply circuit.

Background

With the rapid development of new energy industry and the continuous expansion of market scale in recent years, the step-type development of power electronic devices and energy storage media is initiated, the energy volume ratio performance of the energy storage media is improved, and the development of the energy storage type emergency power supply vehicle provides basic conditions. The energy storage type emergency power supply vehicle is a direction for future development, and can overcome the defects that the traditional fuel oil power supply vehicle cannot realize uninterrupted power supply, has high noise, serious waste gas pollution and the like. The energy storage type emergency power supply vehicle carries a large-capacity lithium battery system and an inverter power supply system, charges electricity for standby at ordinary times, moves to a corresponding place when needing to be used, and then starts the inverter system to perform inversion discharge on direct current of the battery for alternating current electric equipment.

In the prior art, the inverter power supply adopts a non-isolated scheme, the direct current input and the alternating current output are not completely separated, the safety and the reliability of the inverter power supply cannot be guaranteed, and meanwhile, the electromagnetic interference on the direct current input side is also conducted to the output side, so that the electromagnetic interference is difficult to control. Meanwhile, the inverter power supply is isolated by adopting a mode of converting a three-phase transformer on the output alternating current side, and the volume and the weight of the whole machine are large due to the large volume of the three-phase transformer, so that the inverter power supply is not beneficial to vehicle-mounted application.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides an isolated three-phase four-wire system inverter power supply circuit which adopts a two-stage circuit structure form, firstly carries out isolated voltage conversion through an isolated DC/DC conversion module, and then carries out inversion output through a three-phase four-bridge arm inversion module, so that the input and the output are completely isolated.

The purpose of the invention is realized by the following technical scheme: an isolated three-phase four-wire system inverter power circuit comprises one or more isolated DCDC conversion modules, a three-phase four-leg inverter module and a filtering module, wherein the input end of the one or more isolated DCDC conversion modules is electrically connected with an external battery, the output end of the one or more isolated DCDC conversion modules is electrically connected with the input end of the three-phase four-leg inverter module, the output end of the three-phase four-leg inverter module is electrically connected with the input end of the filtering module, and the output end of the filtering module is electrically connected with an external load.

The invention has the beneficial effects that one or more isolation DCDC conversion modules are used for converting the direct current input voltage of the external battery into the direct current bus voltage and simultaneously play the role of input and output isolation. The three-phase four-bridge arm inversion module is used for inverting the direct current bus voltage output by one or more isolation DCDC conversion modules into three-phase four-wire alternating current. The filtering module is used for filtering high-frequency components in alternating current output by the three-phase four-leg inversion module in an inversion mode, so that sine waves of a three-phase four-wire system are output, safety of electric equipment is guaranteed, a three-phase transformer is not used, and the effects of small size, light weight and convenience in vehicle-mounted installation are achieved.

Further, keep apart DCDC conversion module and include two LLC full-bridge conversion units, the input side of two LLC full-bridge conversion units all is connected with external battery electricity, the input side of two LLC full-bridge conversion units is parallelly connected, the output side of two LLC full-bridge conversion units is established ties.

The beneficial effect of adopting above-mentioned further scheme is that, two LLC full-bridge conversion units are inside all to contain a resonance transformer, and its relation of two resonance transformers is that the primary side is established ties, and vice limit is parallelly connected, and two transformers respectively output half power, reach the effect that makes the design of transformer simpler, the volume is littleer, improves product power density.

Further, LLC full-bridge conversion unit includes full-bridge circuit, LC filter circuit, resonance transformer T and output rectifier circuit, the input and the external battery electricity of full-bridge circuit are connected, full-bridge circuit's output with resonance transformer T's primary side electricity is connected, full-bridge circuit with it has to establish ties between the resonance transformer T LC filter circuit, resonance transformer T's secondary with output rectifier circuit's input electricity is connected, output rectifier current's output with four bridge arm contravariant module electricity of three-phase are connected.

The further scheme has the advantages that the two resonance transformers are connected in series at the primary side and in parallel at the secondary side, and the two transformers respectively output half of power, so that the design of the transformers is simpler, the size is smaller, and the power density of products is improved.

Further, the full-bridge circuit comprises a first NMOS tube Q1, a second NMOS tube Q2, a third NMOS tube Q3 and a fourth NMOS tube Q4 which are sequentially connected in series, an external battery is electrically connected with a connection node of the first NMOS tube Q1 and the second NMOS tube Q2 and a connection node of the third NMOS tube Q3 and the fourth NMOS tube Q4, and a connection node of the first NMOS tube Q1 and the third NMOS tube Q3 and a connection node of the second NMOS tube Q2 and the fourth NMOS tube Q4 are electrically connected with a primary side of the resonant transformer T.

Further, the driving signal of the first NMOS transistor Q1 and the driving signal of the fourth NMOS transistor Q4 are in phase and the same, the driving signal of the second NMOS transistor Q2 and the driving signal of the third NMOS transistor Q3 are in phase and the same, the phase difference between the driving signal of the first NMOS transistor Q1 and the driving signal of the second NMOS transistor Q2 is 180 °, and the frequency and the duty ratio of the driving signal of the first NMOS transistor Q1 and the driving signal of the second NMOS transistor Q2 are the same.

Further, the LLC full-bridge conversion unit further includes an input filter capacitor C1, and the input filter capacitor C1 is connected in parallel to the full-bridge circuit.

The beneficial effect of adopting the further scheme is that the effect of input isolation is achieved.

Further, the LLC full-bridge conversion unit further includes an output filter capacitor C2, and the output filter capacitor C2 is connected in parallel to the output rectifying circuit.

The beneficial effect of adopting the further scheme is that the effect of output isolation is achieved.

The three-phase four-bridge arm inverter module comprises an N-phase bridge arm, a U-phase bridge arm, a V-phase bridge arm and a W-phase bridge arm which are connected in parallel, input ends of the N-phase bridge arm, the U-phase bridge arm, the V-phase bridge arm and the W-phase bridge arm are all electrically connected with output ends of the one or more isolated DCDC conversion modules, and output ends of the N-phase bridge arm, the U-phase bridge arm, the V-phase bridge arm and the W-phase bridge arm are all electrically connected with input ends of the filter module.

The further scheme has the advantages that the switching tubes of the N-phase bridge arm are fixed to be in 50% duty ratio open-loop work, and SPWM modulation mode closed-loop control is respectively carried out on the U-phase bridge arm, the V-phase bridge arm and the W-phase bridge arm, so that the problem of three-phase voltage imbalance of the three-phase four-wire system inverter power supply in unbalanced load or nonlinear load application occasions is solved.

Further, the U-phase bridge arm, the V-phase bridge arm and the W-phase bridge arm are consistent in structure, and the U-phase bridge arm comprises a first switch tube S1 and a second switch tube S2 which are connected in series.

The filter module comprises an N-phase LC filter circuit, a U-phase LC filter circuit, a V-phase LC filter circuit and a W-phase LC filter circuit, wherein the output end of the N-phase bridge arm is electrically connected with the N-phase LC filter circuit, the output end of the U-phase bridge arm is electrically connected with the U-phase LC filter circuit, the output end of the V-phase bridge arm is electrically connected with the V-phase LC filter circuit, the W-phase bridge arm is electrically connected with the W-phase LC filter circuit, and the output ends of the N-phase LC filter circuit, the U-phase LC filter circuit, the V-phase LC filter circuit and the W-phase LC filter circuit are electrically connected with an external load.

The technical scheme has the advantages that the high-frequency component filtering module is used for filtering high-frequency components in alternating current output by N-phase bridge arms, U-phase bridge arms, V-phase bridge arms and W-phase bridge arms of a three-phase four-bridge arm inversion module, and therefore the alternating current is output as a three-phase four-wire sine wave.

Drawings

Fig. 1 is a schematic structural diagram of an isolated three-phase four-wire system inverter power circuit according to the present invention;

fig. 2 is a schematic structural diagram of an isolated three-phase four-wire system inverter power circuit for showing an isolated DCDC conversion module according to the present invention;

fig. 3 is a circuit schematic diagram of an isolated three-phase four-wire system inverter power circuit for showing a power supply abnormality judgment component according to the present invention;

fig. 4 is a schematic circuit diagram of an isolated three-phase four-wire system inverter power circuit for showing an LLC full-bridge conversion unit according to the present invention;

FIG. 5 is a schematic circuit diagram of an isolated three-phase four-wire inverter circuit according to the present invention for showing a three-phase four-leg inverter module;

fig. 6 is a schematic circuit diagram of an isolated three-phase four-wire system inverter power circuit for showing a filter module according to the present invention.

Detailed Description

The technical solutions of the present invention are further described in detail below with reference to the accompanying drawings, but the scope of the present invention is not limited to the following.

Examples

Referring to fig. 1, an isolated three-phase four-wire system inverter power circuit includes an isolated DCDC conversion module, a three-phase four-leg inverter module, and a filter module, wherein an input end of the isolated DCDC conversion module is electrically connected to an external battery, and an output end of the isolated DCDC conversion module is electrically connected to an input end of the three-phase four-leg inverter module. The output end of the three-phase four-bridge arm inversion module is electrically connected with the input end of the filtering module, and the output end of the filtering module is electrically connected with an external load.

Specifically, the isolation DCDC conversion module is configured to convert a dc input voltage of the external battery into a dc bus voltage, and also has an input/output isolation function. The three-phase four-leg inverter module is used for inverting the direct-current bus voltage output by the isolation DCDC conversion module into three-phase four-wire alternating current. The filtering module is used for filtering high-frequency components in alternating current output by the three-phase four-leg inverter module in an inverted mode, the alternating current is output as sine waves in a three-phase four-wire system, safety of electric equipment is guaranteed, a three-phase transformer is not used, and the three-phase four-leg inverter module is small in size, light in weight and convenient to mount on a vehicle.

The respective modules are explained in detail in turn below.

Referring to fig. 2 and 3, the isolated DCDC conversion module includes two LLC full-bridge conversion units, input sides of the two LLC full-bridge conversion units are both electrically connected with an external battery, input sides of the two LLC full-bridge conversion units are connected in parallel, and output sides of the two LLC full-bridge conversion units are connected in series. It should be noted that the structures of the two LLC full-bridge conversion units are the same, and the circuit structure of the LLC full-bridge conversion unit is described by taking one LLC full-bridge conversion unit as an example. The LLC full-bridge conversion unit comprises a full-bridge circuit, an LC filter circuit, a resonant transformer T and an output rectification circuit, wherein the input end of the full-bridge circuit is electrically connected with an external battery, the output end of the full-bridge circuit is electrically connected with the primary side of the resonant transformer T, the LC filter circuit is connected in series between the full-bridge circuit and the resonant transformer T, the secondary side of the resonant transformer T is electrically connected with the input end of the output rectification circuit, and the output end of the output rectification current is electrically connected with the three-phase four-bridge-arm.

Referring to fig. 3, it is worth explaining that the primary side of the resonant transformer T of one LLC full-bridge conversion unit is connected in series with the primary side of the resonant transformer T of another LLC full-bridge conversion unit; the secondary side of the resonant transformer T of one LLC full-bridge conversion unit is connected in parallel with the secondary side of the resonant transformer T of another LLC full-bridge conversion unit. The full-bridge circuit comprises a first NMOS tube Q1, a second NMOS tube Q2, a third NMOS tube Q3 and a fourth NMOS tube Q4 which are sequentially connected in series, an external battery is electrically connected with a connection node of the first NMOS tube Q1 and the second NMOS tube Q2 and a connection node of the third NMOS tube Q3 and the fourth NMOS tube Q4, and the connection node of the first NMOS tube Q1 and the third NMOS tube Q3 and the connection node of the second NMOS tube Q2 and the fourth NMOS tube Q4 are electrically connected with the primary side of the resonant transformer T. The LLC full-bridge conversion unit further comprises an input filter capacitor C1, wherein the input filter capacitor C1 is connected in parallel to the full-bridge circuit to isolate the input. The LLC full-bridge conversion unit further comprises an output filter capacitor C2, wherein the output filter capacitor C2 is connected in parallel to the output rectifying circuit to isolate the output.

Specifically, the driving signal of the first NMOS transistor Q1 and the driving signal of the fourth NMOS transistor Q4 are in phase and the same, the driving signal of the second NMOS transistor Q2 and the driving signal of the third NMOS transistor Q3 are in phase and the same, the phase difference between the driving signal of the first NMOS transistor Q1 and the driving signal of the second NMOS transistor Q2 is 180 °, and the frequency and the duty ratio of the driving signal of the first NMOS transistor Q1 and the driving signal of the second NMOS transistor Q2 are the same. The frequencies of the driving signals of the first NMOS transistor Q1, the second NMOS transistor Q2, the third NMOS transistor Q3 and the fourth NMOS transistor Q4 are set according to the resonance parameters, and the duty ratios of the driving signals of the first NMOS transistor Q1, the second NMOS transistor Q2, the third NMOS transistor Q3 and the fourth NMOS transistor Q4 are all fixed to 50%.

Specifically, two LLC full-bridge conversion units all contain a resonance transformer inside, and the relation of its two resonance transformers is that the primary side is established ties, and the secondary side is parallelly connected, and two transformers respectively output half power for the design of transformer is simpler, and the volume is littleer, improves product power density.

Referring to fig. 4, the three-phase four-leg inverter module includes an N-phase leg, a U-phase leg, a V-phase leg, and a W-phase leg connected in parallel, wherein input ends of the N-phase leg, the U-phase leg, the V-phase leg, and the W-phase leg are electrically connected to an output end of the isolated DCDC conversion module, and output ends of the N-phase leg, the U-phase leg, the V-phase leg, and the W-phase leg are electrically connected to an input end of the filter module. It should be noted that the N-phase arm, the U-phase arm, the V-phase arm, and the W-phase arm are identical in structure, and the structures of the N-phase arm, the U-phase arm, the V-phase arm, and the W-phase arm are described below by taking the U-phase arm as an example, where the U-phase arm includes a first switching tube S1 and a second switching tube S2 connected in series.

Specifically, the N-phase bridge arm, the U-phase bridge arm, the V-phase bridge arm and the W-phase bridge arm invert the direct-current bus voltage output by the isolated DCDC conversion module into three-phase four-wire alternating current.

Referring to fig. 5, the filter module includes an N-phase LC filter circuit, a U-phase LC filter circuit, a V-phase LC filter circuit, and a W-phase LC filter circuit, an output end of an N-phase bridge arm is electrically connected to the N-phase LC filter circuit, an output end of a U-phase bridge arm is electrically connected to the U-phase LC filter circuit, an output end of a V-phase bridge arm is electrically connected to the V-phase LC filter circuit, a W-phase bridge arm is electrically connected to the W-phase LC filter circuit, and output ends of the N-phase LC filter circuit, the U-phase LC filter circuit, the V-phase LC filter circuit, and the W-phase LC filter circuit. The N-phase LC filter circuit comprises a fourth inductor L4, the output end of the N-phase bridge arm is electrically connected with one end of a fourth inductor L4, and the other end of the fourth inductor L4 is electrically connected with a terminal N for electrically connecting with an external load.

It should be noted that, referring to fig. 5, the U-phase LC filter circuit, the V-phase LC filter circuit, and the W-phase LC filter circuit are identical in structure, and the structures of the N-phase LC filter circuit, the U-phase LC filter circuit, the V-phase LC filter circuit, and the W-phase LC filter circuit will be described below by taking the U-phase LC filter circuit as an example. The U-phase LC filter circuit comprises a first inductor L1 and a sixth capacitor C6, the output end of the U-phase bridge arm is electrically connected with the first inductor L1, the other end of the first inductor L1 is electrically connected with a terminal A which is used for being electrically connected with an external load, the positive electrode of the sixth capacitor C6 is electrically connected with a connection node between the first inductor L1 and the terminal A, and the negative electrode of the sixth capacitor C6 is electrically connected with the terminal N.

The three-phase four-leg inverter module is used for filtering high-frequency components in alternating current output by the N-phase bridge arm, the U-phase bridge arm, the V-phase bridge arm and the W-phase bridge arm of the three-phase four-leg inverter module, so that a three-phase four-wire sine wave is output.

The specific implementation manner of this embodiment is: the isolation DCDC conversion module is used for converting the direct-current input voltage of the external battery into direct-current bus voltage and plays a role in input and output isolation. The three-phase four-leg inverter module is used for inverting the direct-current bus voltage output by the isolation DCDC conversion module into three-phase four-wire alternating current. The filtering module is used for filtering high-frequency components in alternating current output by the three-phase four-leg inverter module in an inverted mode, the alternating current is output as sine waves in a three-phase four-wire system, safety of electric equipment is guaranteed, a three-phase transformer is not used, and the three-phase four-leg inverter module is small in size, light in weight and convenient to mount on a vehicle.

Referring to fig. 6, it is worth to be noted that in another embodiment, power expansion may also be performed, a plurality of isolated DCDC conversion modules are provided as needed, input ends of the isolated DCDC conversion modules are electrically connected to an external battery, output ends of the isolated DCDC conversion modules are electrically connected to input ends of a three-phase four-leg inverter module, and the isolated DCDC conversion modules are connected in parallel with each other.

The foregoing is merely a preferred embodiment of the invention, it is to be understood that the invention is not limited to the forms disclosed herein, but is not intended to be exhaustive or to limit the invention to other embodiments, and to various other combinations, modifications, and environments and may be modified within the scope of the inventive concept as expressed herein, by the teachings or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.