阅读说明：本技术 光伏逆变器及电容放电电路 (Photovoltaic inverter and capacitor discharge circuit ) 是由 李晓锋 吴良材 邓蜀云 于 2019-12-16 设计创作，主要内容包括：本发明公开了一种光伏逆变器及电容放电电路,在电容的放电回路上设置了控制开关,在控制开关导通时电容通过放电回路放电,通过切换开关控制控制开关的导通或关闭,而切换开关则由第一电源和第二电源进行控制,在系统有电时,第一电源给电压储能件充电,电压储能件上保持有电荷,若系统掉电,第一电源和第二电源断电,切换开关控制第一电容上电荷给控制开关供电,控制开关导通,使得电容进行放电,实现了在系统掉电的情况下,电容能够自动进行放电。(The invention discloses a photovoltaic inverter and a capacitor discharging circuit, wherein a control switch is arranged on a discharging loop of a capacitor, the capacitor is discharged through the discharging loop when the control switch is switched on, the switching on or off of the control switch is controlled through a change-over switch, the change-over switch is controlled by a first power supply and a second power supply, when a system is powered on, the first power supply charges a voltage energy storage part, charges are kept on the voltage energy storage part, if the system is powered off, the first power supply and the second power supply are powered off, the change-over switch controls the charges on the first capacitor to supply power to the control switch, and the control switch is switched on, so that the capacitor is discharged, and the capacitor can be automatically discharged under the condition that the system is powered off.)

1. A capacitor discharge circuit is used for discharging a capacitor and is characterized by comprising a first resistor, a control switch, a change-over switch, a first power supply and a voltage energy storage element;

the control switch comprises a first pole, a second pole and a control pole, the positive pole of the capacitor is connected with the input end of the first resistor, the output end of the first resistor is connected with the first pole of the control switch, and the second pole of the control switch is connected with the ground;

the negative pole of the voltage energy storage part is connected with the ground, the positive pole of the voltage energy storage part is connected with the first end of the change-over switch, the second end of the change-over switch is switched between the positive pole of the first power supply and the control pole of the control switch, the positive pole of the voltage energy storage part is connected to the positive pole of the first power supply when the capacitor does not need to be discharged, and the control pole of the control switch is connected to the positive pole of the voltage energy storage part when the capacitor needs to be discharged.

2. The capacitance discharge circuit of claim 1, further comprising a control module coupled to the control terminal of the switch for controlling the switch to switch between the first terminal and the second terminal.

3. The capacitive discharge circuit of claim 2 wherein the control module comprises a second power supply, the anode of the second power supply being coupled to the control terminal of the switch and the cathode of the second power supply being coupled to ground.

4. The capacitive discharge circuit of claim 3 wherein the switch is a single pole double throw relay having a control terminal comprising a coil, a first control terminal disposed at one end of the coil, and a second control terminal disposed at the other end of the coil, the first control terminal being connected to the positive terminal of the second power source, the second control terminal being connected to ground.

5. The capacitive discharge circuit of claim 1 wherein said voltage storage element is a first capacitor.

6. The capacitive discharge circuit of claim 1 further comprising a second resistor, a third resistor, and a fourth resistor;

when the capacitor needs to be discharged, the second end of the change-over switch is connected with the input end of the second resistor, and the output end of the second resistor is connected with the control end of the control switch;

when the capacitor does not need to be discharged, the anode of the first power supply is connected with the input end of the fourth resistor, and the output end of the fourth resistor is connected with the second end of the change-over switch;

the control end of the control switch is also connected with the input end of the third resistor, and the output end of the third resistor is connected with the ground.

7. A photovoltaic inverter comprises a solar battery, a boosting module, an inversion module, a power supply module and a power grid, wherein the boosting module comprises a capacitor, and the input end of the boosting module is connected with the anode of the solar battery and is used for boosting the direct-current voltage output by the solar battery and then storing the boosted direct-current voltage in the capacitor; the input end of the inversion module is connected with the output end of the boosting module and used for converting the boosted direct-current voltage into alternating-current voltage; the output end of the inversion module is connected with a power grid and used for outputting alternating current to the power grid; the power supply module is used for supplying power to the boosting module and the inversion module; the boost circuit of any one of claims 1 to 6, further comprising a capacitor discharge circuit for discharging a capacitor in the boost module.

8. The photovoltaic inverter of claim 7, wherein the first and second power sources are powered by a power module.

9. The pv inverter of claim 7 wherein the boost module comprises an inductor, a first switch, a diode, and a capacitor, wherein the anode of the solar cell is coupled to the input of the inductor, the output of the inductor is coupled to the input of the diode, the output of the diode is coupled to the anode of the capacitor, the cathode of the capacitor is coupled to ground, the output of the inductor is further coupled to the first pole of the first switch, and the second pole of the first switch is coupled to ground.

10. The photovoltaic inverter of claim 9, wherein the inverter module comprises a second switch, a third switch, a fourth switch, and a fifth switch, wherein a first pole of the second switch is connected to the positive pole of the capacitor, a second pole of the second switch is connected to the first pole of the third switch, a second pole of the third switch is connected to the negative pole of the capacitor, a first pole of the fourth switch is connected to the positive pole of the capacitor, a second pole of the fourth switch is connected to the first pole of the fifth switch, and a second pole of the fifth switch is connected to the negative pole of the capacitor; a node A is led out between the second pole of the second switch and the first pole of the third switch, a node B is led out between the second pole of the fourth switch and the first pole of the fifth switch, and the power grid is connected between the node A and the node B.

Technical Field

The invention relates to the field of solar photovoltaic inverters, in particular to a photovoltaic inverter and a capacitor discharge circuit.

Background

After the device containing the capacitor is powered off or closed, the capacitor can often store a large amount of charges, if the capacitance value of the capacitor is large, the existing high voltage of the capacitor can cause damage to maintenance personnel or influence the restarting of the device, for example, the capacitor in a boosting module in a photovoltaic inverter, a solar battery and an inductor can charge the capacitor in the using process, so that the capacitor with the large capacitance value has the high voltage, and if a power supply module of the photovoltaic inverter is powered off, the existing high voltage of the capacitor is harmful to the operation, so that the capacitor needs to be discharged as soon as possible.

Disclosure of Invention

The invention mainly solves the technical problem of providing a circuit for automatically discharging a capacitor.

According to a first aspect, an embodiment provides a capacitor discharge circuit for discharging a capacitor, including a first resistor, a control switch, a first power supply and a voltage energy storage element;

the control switch comprises a first pole, a second pole and a control pole, the positive pole of the capacitor is connected with the input end of the first resistor, the output end of the first resistor is connected with the first pole of the control switch, and the second pole of the control switch is connected with the ground;

the negative pole of the voltage energy storage part is connected with the ground, the positive pole of the voltage energy storage part is connected with the first end of the change-over switch, the second end of the change-over switch is switched between the positive pole of the first power supply and the control pole of the control switch, the positive pole of the voltage energy storage part is connected to the positive pole of the first power supply when the capacitor does not need to be discharged, and the control pole of the control switch is connected to the positive pole of the voltage energy storage part when the capacitor needs to be discharged.

The control module is connected with the control end of the change-over switch and used for controlling the change-over switch to switch between the first end and the second end.

Furthermore, the control module comprises a second power supply, wherein the anode of the second power supply is connected with the control end of the change-over switch, and the cathode of the second power supply is connected with the ground.

Furthermore, the change-over switch is a single-pole double-throw relay, the control end of the change-over switch comprises a coil, a first control end arranged at one end of the coil and a second control end arranged at the other end of the coil, the first control end is connected with the anode of the second power supply, and the second control end is connected with the ground.

Further, the voltage energy storage element is a first capacitor.

Further, the circuit also comprises a second resistor, a third resistor and a fourth resistor;

when the capacitor needs to be discharged, the second end of the change-over switch is connected with the input end of the second resistor, and the output end of the second resistor is connected with the control end of the control switch;

when the capacitor does not need to be discharged, the anode of the first power supply is connected with the input end of the fourth resistor, and the output end of the fourth resistor is connected with the second end of the change-over switch;

the control end of the control switch is also connected with the input end of the third resistor, and the output end of the third resistor is connected with the ground.

According to a second aspect, an embodiment provides a photovoltaic inverter, which includes a solar battery, a boosting module, an inverting module, a power supply module, and a power grid, where the boosting module includes a capacitor, and an input end of the boosting module is connected to a positive electrode of the solar battery, and is configured to boost a dc voltage output by the solar battery and store the dc voltage in the capacitor; the input end of the inversion module is connected with the output end of the boosting module and used for converting the boosted direct-current voltage into alternating-current voltage; the output end of the inversion module is connected with a power grid and used for outputting alternating current to the power grid; the power supply module is used for supplying power to the boosting module and the inversion module; the boost module comprises a boost module, a capacitor discharge circuit and a control circuit, wherein the boost module comprises a capacitor discharge circuit used for discharging a capacitor in the boost module.

Further, the first power supply and the second power supply are supplied with power through a power supply module.

Furthermore, the boosting module comprises an inductor, a first switch, a diode and a capacitor, wherein the anode of the solar battery is connected with the input end of the inductor, the output end of the inductor is connected with the input end of the diode, the output end of the diode is connected with the anode of the capacitor, the cathode of the capacitor is connected with the ground, the output end of the inductor is further connected with the first pole of the first switch, and the second pole of the first switch is connected with the ground.

Furthermore, the inverter module comprises a second switch, a third switch, a fourth switch and a fifth switch, wherein a first pole of the second switch is connected with the positive pole of the capacitor, a second pole of the second switch is connected with the first pole of the third switch, a second pole of the third switch is connected with the negative pole of the capacitor, a first pole of the fourth switch is connected with the positive pole of the capacitor, a second pole of the fourth switch is connected with the first pole of the fifth switch, and a second pole of the fifth switch is connected with the negative pole of the capacitor; a node A is led out between the second pole of the second switch and the first pole of the third switch, a node B is led out between the second pole of the fourth switch and the first pole of the fifth switch, and the power grid is connected between the node A and the node B.

According to the photovoltaic inverter and the capacitor discharging circuit of the embodiment, the control switch is arranged on the discharging loop of the capacitor, when the control switch is switched on, the capacitor is discharged through the discharging loop, the switching on or off of the control switch is controlled through the switching switch, the switching switch is controlled by the first power supply and the second power supply, when the system is electrified, the first power supply charges the voltage energy storage part, the voltage energy storage part keeps charges, if the system is powered off, the first power supply and the second power supply are powered off, the switching switch controls the charges on the first capacitor to supply power to the control switch, the control switch is switched on, the capacitor is discharged, and the capacitor can be automatically discharged under the condition that the system is powered off.

Drawings

FIG. 1 is a schematic diagram of a capacitor discharge circuit;

FIG. 2 is a circuit schematic of a photovoltaic inverter with a capacitive discharge circuit according to an embodiment;

fig. 3 is a schematic structural diagram of a single-pole double-throw relay according to an embodiment.

Detailed Description

The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.

Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).

The existing capacitor discharge is usually realized by controlling the capacitor through a controller, however, the controller is powered off after power failure, and the capacitor discharge cannot be controlled.

In an embodiment of the present invention, referring to fig. 1, fig. 1 is a schematic diagram of a capacitor discharge circuit, when a capacitor does not need to be discharged, a second end of a switch is controlled by a first power supply to be connected to a second power supply, so that the second power supply charges a voltage energy storage device, when the capacitor needs to be discharged, the first power supply is powered off, the second end of the switch is connected to a control electrode of the control switch, so that the voltage energy storage device is connected to the control electrode of the control switch, and when the control switch is turned on, an anode of the capacitor discharges through a first resistor R1.

Since the capacitance value of the capacitor in the boost module of the photovoltaic inverter is large, and a large voltage exists on the capacitor after the photovoltaic inverter is powered off, the embodiment explains the specific implementation of the capacitor discharge circuit in the photovoltaic inverter by taking the photovoltaic inverter as an example.