A photovoltaic inverter safety drive control circuit

Abstract

The application discloses a kind of photovoltaic inverter safety drive control circuit, it is related to photovoltaic inverter technical field, including micro-control module, control photovoltaic inverter to the photovoltaic module provided photovoltaic electric energy carries out inverter processing, when inverting, through the upper capacitor and lower capacitor in photovoltaic inverter module share photovoltaic electric energy and through the neutral point current between control upper capacitor and lower capacitor, actively control the voltage balance of upper capacitor and lower capacitor, and according to the size relationship of the voltage of upper capacitor and lower capacitor and the half of photovoltaic electric energy voltage, control compensation module and compensation capacitor module carry out electric energy compensation and voltage division processing to photovoltaic inverter module, further maintain the balanced state of upper capacitor and lower capacitor.The application photovoltaic inverter safety drive control circuit can reduce the voltage stress of switch tube, reduce switching loss, prolong the service life of photovoltaic inverter module, improve electric energy conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic inverter technology, specifically a safety drive control circuit for a photovoltaic inverter. Background Technology

[0002] A photovoltaic inverter is a device that converts photovoltaic power into alternating current. In the existing technology, when providing single-phase alternating current, an inverter composed of four IGBTs is used to directly invert the photovoltaic power that has been processed by MPPT. However, due to the influence of sunlight, the voltage of the power input to the photovoltaic inverter fluctuates. The IGBTs need to withstand the constantly changing power. In addition, the switching losses and electromagnetic interference lead to a decrease in the service life of the IGBTs and a reduction in the power conversion efficiency. Therefore, improvements are needed. Summary of the Invention

[0003] This invention provides a safety drive control circuit for a photovoltaic inverter to solve the problems mentioned in the background art.

[0004] According to an embodiment of the present invention, a safety drive control circuit for a photovoltaic inverter is provided, comprising: Photovoltaic modules are used for photoelectric conversion and to provide photovoltaic power. A photovoltaic inverter module, connected to a photovoltaic module, is used to convert photovoltaic power into DC power. During the power conversion process, the photovoltaic power is shared by an upper capacitor and a lower capacitor, and the neutral point current between the upper and lower capacitors is controlled by injecting a common bias voltage, thereby actively controlling the voltage balance between the upper and lower capacitors. The compensation control module is connected to the photovoltaic module and the compensation capacitor module. It is used to stabilize the photovoltaic power and perform dual-path energy storage processing, and provide the first compensation power and the second compensation power respectively. When the voltage of the upper capacitor is less than half of the photovoltaic power voltage, the first compensation power is transmitted to the compensation capacitor module. When the voltage of the lower capacitor is less than half of the photovoltaic power voltage, the second compensation power is transmitted to the compensation capacitor module. The compensation capacitor module is connected to the photovoltaic inverter module. When the voltage of the upper capacitor is greater than half of the photovoltaic voltage, the first compensation capacitor stores the electrical energy released by the upper capacitor. When the voltage of the upper capacitor is less than half of the photovoltaic voltage, the first compensation energy is stored and the upper capacitor is compensated. When the voltage of the lower capacitor is greater than half of the photovoltaic voltage, the second compensation capacitor stores the electrical energy released by the lower capacitor. When the voltage of the lower capacitor is less than half of the photovoltaic voltage, the second compensation energy is stored and the lower capacitor is compensated. The microcontroller module connects to the photovoltaic module, photovoltaic inverter module, compensation control module, and compensation capacitor module. It controls the photovoltaic inverter module to perform photoelectric conversion, detects the voltage of the upper and lower capacitors, and changes the connection state between the compensation capacitor module and the photovoltaic inverter module when the voltage of the upper and lower capacitors is not equal to half of the photovoltaic voltage. Based on the magnitude of the voltage of the upper and lower capacitors and the photovoltaic voltage, it controls the compensation capacitor module to store the electrical energy released by the upper or lower capacitors, or controls the power transmission state of the compensation control module and the compensation state of the compensation capacitor module to the photovoltaic inverter module.

[0005] As a further embodiment of the present invention: the photovoltaic module includes a photovoltaic power supply and a third capacitor; the photovoltaic inverter module includes a first power transistor, a second power transistor, a third power transistor, a fourth power transistor, a fifth power transistor, a sixth power transistor, a seventh power transistor, an eighth power transistor, a first diode, a third diode, a fourth diode, a first inductor, an output port, a second diode, a first capacitor, and a second capacitor; the microcontroller module includes a first controller; Preferably, the first terminal of the photovoltaic power supply is connected to the collector of the first power transistor, the positive terminal of the first capacitor, and the collector of the second power transistor, and is connected to the second terminal of the photovoltaic power supply, the emitter of the fourth power transistor, and the emitter of the eighth power transistor through the third capacitor. The emitter of the first power transistor is connected to the collector of the third power transistor and the anode of the first diode. The emitter of the fifth power transistor is connected to the collector of the sixth power transistor and the cathode of the third diode. The anode of the third diode is connected to the cathode of the fourth diode, the anode of the first diode, the cathode of the second diode, the positive terminal of the second capacitor, and ground. The emitter of the third power transistor is connected to the anode of the second diode and the collector of the fourth power transistor. The anode of the four diodes is connected to the emitter of the seventh power transistor and the collector of the eighth power transistor. The emitter of the second power transistor is connected to the collector of the third power transistor and connected to one end of the output port through the first inductor. The emitter of the sixth power transistor is connected to the other end of the output port and the collector of the seventh power transistor. The gates of the first power transistor, the second power transistor, the third power transistor, the fourth power transistor, the fifth power transistor, the sixth power transistor, the seventh power transistor, and the eighth power transistor are respectively connected to the IO1, IO10, IO9, IO2, IO3, IO12, IO11, and IO4 terminals of the first controller.

[0006] As a further embodiment of the present invention: the compensation capacitor module includes a first control transistor, a first compensation capacitor, a fifth diode, a first switching transistor, a first thyristor, a first resistor, and a first voltage regulator. Preferably, the source of the first control transistor is connected to the negative terminal of the first capacitor and one end of the first thyristor, the drain of the first control transistor is connected to the positive terminal of the first compensation capacitor, the gate of the first control transistor is connected to the anode of the fifth diode and the IO5 terminal of the first controller, the cathode of the fifth diode is connected to the base of the first switching transistor, the collector of the first switching transistor is connected to the control terminal of the first thyristor and connected to the first voltage regulator through the first resistor, and the other end of the first thyristor is connected to the negative terminal of the first compensation capacitor, the emitter of the first switching transistor, the anode of the first diode and ground.

[0007] As a further embodiment of the present invention: the compensation capacitor module further includes a second switching transistor, a second control transistor, a second thyristor, a sixth diode, a second compensation capacitor, and a second resistor; Preferably, the collector of the second switching transistor is connected to the control terminal of the second switching transistor and connected to the first voltage regulator through the second resistor. One end of the second thyristor is connected to the source of the second control transistor and the negative terminal of the second capacitor. The other end of the second switching transistor is connected to the negative terminal of the second compensation capacitor and the emitter of the fourth power transistor. The drain of the second control transistor is connected to the positive terminal of the second compensation capacitor. The emitter of the second switching transistor is grounded. The gate of the second control transistor is connected to the IO6 terminal of the first controller and the anode of the sixth diode. The cathode of the sixth diode is connected to the base of the second switching transistor.

[0008] As a further embodiment of the present invention: the compensation control module includes a voltage regulator, a seventh diode, an eighth diode, a ninth diode, a first energy storage device, and a second energy storage device; Preferably, the input terminal of the voltage regulator is connected to the first terminal of the photovoltaic power supply, the output terminal of the voltage regulator is connected to the anode of the seventh diode and the anode of the eighth diode, the cathode of the seventh diode is connected to the first terminal of the second energy storage device, the cathode of the eighth diode is connected to the first terminal of the first energy storage device, the second terminal of the second energy storage device is connected to the anode of the ninth diode, the negative terminal of the first compensation capacitor and the ground terminal, and the cathode of the ninth diode is connected to the second terminal of the first energy storage device, the ground terminal of the voltage regulator, the negative terminal of the second compensation capacitor and the second terminal of the photovoltaic power supply.

[0009] As a further embodiment of the present invention: the compensation control module also includes a third control transistor and a tenth diode; Preferably, the drain of the third control transistor is connected to the cathode of the eighth diode, the source of the third control transistor is connected to the anode of the tenth diode, the cathode of the tenth diode is connected to the positive terminal of the second compensation capacitor, and the gate of the third control transistor is connected to the IO7 terminal of the first controller.

[0010] As a further embodiment of the present invention, the compensation control module also includes a fourth control transistor and an eleventh diode; Preferably, the drain of the fourth control transistor is connected to the cathode of the seventh diode, the source of the fourth control transistor is connected to the anode of the eleventh diode, the cathode of the eleventh diode is connected to the positive terminal of the first compensation capacitor, and the gate of the fourth control transistor is connected to the IO8 terminal of the first controller.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: The photovoltaic inverter safety drive control circuit of the present invention can be controlled by a microcontroller module to perform inversion processing on the photovoltaic power provided by the photovoltaic module. During inversion, the photovoltaic power is shared by the upper and lower capacitors in the photovoltaic inverter module, and the neutral point current between the upper and lower capacitors is controlled by injecting a common bias voltage. The voltage balance between the upper and lower capacitors is actively controlled to reduce the voltage stress of the switching transistors, reduce switching losses, and extend the service life of the photovoltaic inverter module. Based on the relationship between the voltage of the upper and lower capacitors and half of the photovoltaic power voltage, the compensation module and the compensation capacitor module are controlled to perform power compensation and voltage division processing on the photovoltaic inverter module, further maintaining the balance state of the upper and lower capacitors and improving the power conversion efficiency. Attached Figure Description

[0012] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic block diagram of a photovoltaic inverter safety drive control circuit provided in an embodiment of the present invention.

[0013] Figure 2 This is a circuit diagram of a photovoltaic inverter safety drive control circuit provided in an embodiment of the present invention.

[0014] Figure 3 The circuit diagram of the compensation control module provided in the embodiment of the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Please see Figure 1 A safety drive control circuit for a photovoltaic inverter, comprising: Photovoltaic module 1 is used for photoelectric conversion and provides photovoltaic power. Photovoltaic inverter module 2, connected to photovoltaic module 1, is used to convert photovoltaic power into DC power. During the power conversion process, the photovoltaic power is shared by the upper and lower capacitors, and the neutral point current between the upper and lower capacitors is controlled by injecting a common bias voltage, thereby actively controlling the voltage balance between the upper and lower capacitors. The compensation control module 3 is connected to the photovoltaic module 1 and the compensation capacitor module 4. It is used to stabilize the photovoltaic power and perform dual-path energy storage processing, and provide the first compensation power and the second compensation power respectively. When the voltage of the upper capacitor is less than half of the photovoltaic power voltage, the first compensation power is transmitted to the compensation capacitor module 4. When the voltage of the lower capacitor is less than half of the photovoltaic power voltage, the second compensation power is transmitted to the compensation capacitor module 4. The compensation capacitor module 4 is connected to the photovoltaic inverter module 2. It is used to store the electrical energy released by the upper capacitor through the first compensation capacitor when the voltage of the upper capacitor is greater than half of the photovoltaic voltage, and to store the first compensation energy and compensate the upper capacitor when the voltage of the upper capacitor is less than half of the photovoltaic voltage. When the voltage of the lower capacitor is greater than half of the photovoltaic voltage, it stores the electrical energy released by the lower capacitor through the second compensation capacitor, and to store the second compensation energy and compensate the lower capacitor when the voltage of the lower capacitor is less than half of the photovoltaic voltage. The microcontroller module 5 is connected to the photovoltaic module 1, the photovoltaic inverter module 2, the compensation control module 3, and the compensation capacitor module 4. It is used to control the photovoltaic inverter module 2 to perform photoelectric conversion, detect the voltage of the upper and lower capacitors, and change the connection state between the compensation capacitor module 4 and the photovoltaic inverter module 2 when the voltage of the upper and lower capacitors is not equal to half of the photovoltaic power voltage. Based on the magnitude of the voltage of the upper and lower capacitors and the photovoltaic power voltage, it controls the compensation capacitor module 4 to store the electrical energy released by the upper or lower capacitors, or controls the power transmission state of the compensation control module 3 and the compensation state of the compensation capacitor module 4 for the photovoltaic inverter module 2.

[0017] In a specific embodiment, the photovoltaic module 1 can be a photovoltaic circuit composed of a photovoltaic power source and a capacitor to perform photoelectric conversion and provide photovoltaic power. The photovoltaic inverter module 2 can be a photovoltaic inverter circuit composed of IGBTs, diodes, capacitors, inductors, etc., to perform DC-AC inversion processing. During the inversion process, the upper and lower capacitors perform voltage division processing, and the neutral point current between the upper and lower capacitors is controlled by a carrier pulse width modulation method that injects a common bias voltage containing second harmonic components, thereby actively controlling the voltage balance between the upper and lower capacitors. When the voltages of the upper and lower capacitors are balanced, the voltage is equal to half of the photovoltaic power voltage. The compensation control module 3 can be a compensation control circuit composed of an energy storage device, a voltage regulator, a field-effect transistor, etc. The system can regulate and store photovoltaic power, release the stored energy, and charge the two sets of compensation energy in the compensation capacitor module 4. The compensation capacitor module 4 can be a compensation control circuit composed of compensation capacitors, transistors, field-effect transistors, and thyristors. By changing the connection state with the photovoltaic inverter module 2, it can control the compensation capacitor to store the energy released by the upper and lower capacitors in the photovoltaic inverter module 2, and then perform voltage division. It can also store the energy released by the compensation control module 3 and perform voltage compensation on the photovoltaic inverter module 2. The microcontroller module 5 can be a microcontroller circuit composed of a single-chip microcomputer, which integrates many components such as an arithmetic unit, a controller, a memory, and input / output devices to realize functions such as signal processing, data storage, module control, and timing control.

[0018] In this embodiment, please refer to Figure 2 and Figure 3 The photovoltaic module 1 includes a photovoltaic power supply and a third capacitor C3; the photovoltaic inverter module 2 includes a first power transistor Q1, a second power transistor Q2, a third power transistor Q3, a fourth power transistor Q4, a fifth power transistor Q5, a sixth power transistor Q6, a seventh power transistor Q7, an eighth power transistor Q8, a first diode D1, a third diode D3, a fourth diode D4, a first inductor L1, an output port, a second diode D2, a first capacitor C1, and a second capacitor C2; the microcontroller module 5 includes a first controller U1; Specifically, the first terminal of the photovoltaic power supply is connected to the collector of the first power transistor Q1, the positive terminal of the first capacitor C1, and the collector of the second power transistor Q2. It is also connected to the second terminal of the photovoltaic power supply, the emitter of the fourth power transistor Q4, and the emitter of the eighth power transistor Q8 via the third capacitor C3. The emitter of the first power transistor Q1 is connected to the collector of the third power transistor Q3 and the anode of the first diode D1. The emitter of the fifth power transistor Q5 is connected to the collector of the sixth power transistor Q6 and the cathode of the third diode D3. The anode of the third diode D3 is connected to the cathode of the fourth diode D4, the anode of the first diode D1, the cathode of the second diode D2, the positive terminal of the second capacitor C2, and ground. The emitter of the third power transistor Q3 is connected to the anode of the second diode D2 and the collector of the fourth power transistor Q4. The anode of the fourth diode D4 is connected to the emitter of the seventh power transistor Q7 and the collector of the eighth power transistor Q8. The emitter of the second power transistor Q2 is connected to the collector of the third power transistor Q3 and connected to one end of the output port through the first inductor L1. The emitter of the sixth power transistor Q6 is connected to the other end of the output port and the collector of the seventh power transistor Q7. The gates of the first power transistor Q1, the second power transistor Q2, the third power transistor Q3, the fourth power transistor Q4, the fifth power transistor Q5, the sixth power transistor Q6, the seventh power transistor Q7, and the eighth power transistor Q8 are respectively connected to the IO1, IO10, IO9, IO2, IO3, IO12, IO11, and IO4 terminals of the first controller U1.

[0019] In a specific embodiment, the first power transistor Q1, the second power transistor Q2, the third power transistor Q3, the fourth power transistor Q4, the fifth power transistor Q5, the sixth power transistor Q6, the seventh power transistor Q7, and the eighth power transistor Q8 can all be IGBTs. The pulse signal injected into the first power transistor Q1, the second power transistor Q2, the third power transistor Q3, the fourth power transistor Q4, the fifth power transistor Q5, the sixth power transistor Q6, the seventh power transistor Q7, and the eighth power transistor Q8 contains a common bias voltage with a second harmonic component. The first capacitor C1 and the second capacitor C2 serve as the upper capacitor and the lower capacitor, respectively. The first diode D1, the second diode D2, the third diode D3, and the fourth diode D4 are clamping diodes, connecting the power transistors and the neutral point, providing a neutral point current path. The first controller U1 can be an STM32 microcontroller.

[0020] Furthermore, the compensation capacitor module 4 includes a first control transistor M1, a first compensation capacitor CB1, a fifth diode D5, a first switching transistor V1, a first thyristor S1, a first resistor R1, and a first voltage regulator VCC1. Specifically, the source of the first control transistor M1 is connected to the negative terminal of the first capacitor C1 and one end of the first thyristor S1, the drain of the first control transistor M1 is connected to the positive terminal of the first compensation capacitor CB1, the gate of the first control transistor M1 is connected to the anode of the fifth diode D5 and the IO5 terminal of the first controller U1, the cathode of the fifth diode D5 is connected to the base of the first switching transistor V1, the collector of the first switching transistor V1 is connected to the control terminal of the first thyristor S1 and connected to the first voltage regulator VCC1 through the first resistor R1, and the other end of the first thyristor S1 is connected to the negative terminal of the first compensation capacitor CB1, the emitter of the first switching transistor V1, the anode of the first diode D1 and ground.

[0021] In a specific embodiment, the first control transistor M1 can be an N-channel field-effect transistor; the first switching transistor V1 can be an NPN transistor to control the first thyristor S1 to be turned off; the first thyristor S1 can be a bidirectional thyristor, triggered by the first voltage regulator VCC1 and the first resistor R1.

[0022] Furthermore, the compensation capacitor module 4 also includes a second switching transistor V2, a second control transistor M2, a second thyristor S2, a sixth diode D6, a second compensation capacitor CB2, and a second resistor R2; Specifically, the collector of the second switch V2 is connected to the control terminal of the second switch V2 and connected to the first voltage regulator VCC1 through the second resistor R2. One end of the second thyristor S2 is connected to the source of the second control transistor M2 and the negative terminal of the second capacitor C2. The other end of the second switch V2 is connected to the negative terminal of the second compensation capacitor CB2 and the emitter of the fourth power transistor Q4. The drain of the second control transistor M2 is connected to the positive terminal of the second compensation capacitor CB2. The emitter of the second switch V2 is grounded. The gate of the second control transistor M2 is connected to the IO6 terminal of the first controller U1 and the anode of the sixth diode D6. The cathode of the sixth diode D6 is connected to the base of the second switch V2.

[0023] In a specific embodiment, the second switching transistor V2 can be an NPN transistor to control the second thyristor S2 to be turned off; the second thyristor S2 can be a bidirectional thyristor, triggered by the first voltage regulator VCC1 and the second resistor R2.

[0024] Furthermore, the compensation control module 3 includes a voltage regulator, a seventh diode D7, an eighth diode D8, a ninth diode D9, a first energy storage device, and a second energy storage device. Specifically, the input terminal of the voltage regulator is connected to the first terminal of the photovoltaic power supply, the output terminal of the voltage regulator is connected to the anode of the seventh diode D7 and the anode of the eighth diode D8, the cathode of the seventh diode D7 is connected to the first terminal of the second energy storage device, the cathode of the eighth diode D8 is connected to the first terminal of the first energy storage device, the second terminal of the second energy storage device is connected to the anode of the ninth diode D9, the negative terminal of the first compensation capacitor CB1 and the ground terminal, and the cathode of the ninth diode D9 is connected to the second terminal of the first energy storage device, the ground terminal of the voltage regulator, the negative terminal of the second compensation capacitor CB2 and the second terminal of the photovoltaic power supply.

[0025] In a specific embodiment, the voltage stabilizing device can be composed of a DC-DC voltage regulator; both the first energy storage device and the second energy storage device can be lithium batteries.

[0026] Furthermore, the compensation control module 3 also includes a third control transistor M3 and a tenth diode D10; Specifically, the drain of the third control transistor M3 is connected to the cathode of the eighth diode D8, the source of the third control transistor M3 is connected to the anode of the tenth diode D10, the cathode of the tenth diode D10 is connected to the positive terminal of the second compensation capacitor CB2, and the gate of the third control transistor M3 is connected to the IO7 terminal of the first controller U1.

[0027] In a specific embodiment, the third control transistor M3 can be an N-channel field-effect transistor.

[0028] Furthermore, the compensation control module 3 also includes a fourth control transistor M4 and an eleventh diode D11; Specifically, the drain of the fourth control transistor M4 is connected to the cathode of the seventh diode D7, the source of the fourth control transistor M4 is connected to the anode of the eleventh diode D11, the cathode of the eleventh diode D11 is connected to the positive terminal of the first compensation capacitor CB1, and the gate of the fourth control transistor M4 is connected to the IO8 terminal of the first controller U1.

[0029] In a specific embodiment, the fourth control transistor M4 can be an N-channel field-effect transistor.

[0030] The working principle of a photovoltaic inverter safety drive control circuit of the present invention is as follows: A photovoltaic power source performs photoelectric conversion and provides photovoltaic power. A third capacitor C3 performs filtering, and the photovoltaic inverter module 2 performs inversion processing. In the photovoltaic inverter module 2, during the positive half-cycle, a first capacitor C1 stores energy and provides half of the photovoltaic power voltage as a positive voltage. A first controller U1 controls the first power transistor Q1 and the second power transistor Q2 to conduct, so that the energy released by the first capacitor C1 is transmitted to the output port through the first power transistor Q1 and the second power transistor Q2. At the same time, the first controller U1 controls the seventh power transistor Q7 to conduct, and then the seventh power transistor Q7, the fourth diode D4, and the first thyristor S1 form a circuit with the first capacitor C1. During the negative half-cycle… The second capacitor C2 stores energy and provides a negative voltage, half the voltage of the photovoltaic power, through its negative terminal. The first controller U1 controls the third power transistor Q3 and the fourth power transistor Q4 to conduct, so that the energy released by the second capacitor C2 forms a circuit through the third power transistor Q3, the fourth power transistor Q4, the output port, the second thyristor S2, the seventh power transistor Q7, and the fourth diode D4, in order to provide a negative value to the first terminal of the output port. At the same time, between the positive and negative half-cycles, zero-level control can be performed by controlling the conduction of the second power transistor Q2 and the third power transistor Q3, thereby reducing the voltage jump amplitude, providing a freewheeling circuit, and balancing the first capacitor C1 and the second capacitor C2. Similarly, the fifth power transistor Q5, the sixth power transistor Q6, and the seventh power transistor Q4 can be controlled to achieve zero-level control. The conduction states of Q7 and the eighth power transistor Q8 provide positive or negative electrical energy to the second terminal of the output port, allowing the first and second terminals of the output port to switch between positive voltage, zero potential, and negative voltage, thus completing the inverter operation. Simultaneously, the first controller U1 detects the voltage states of the first capacitor C1 and the second capacitor C2, specifically through voltage sampling via a voltage divider. By controlling the compensation and voltage divider states based on the relationship between the voltage of the first capacitor C1 or the second capacitor C2 and half the photovoltaic voltage, the voltage regulator stabilizes the photovoltaic energy supplied by the photovoltaic power source and charges the first and second energy storage devices. Taking the first capacitor C1 as an example, when the voltage of the first capacitor C1 is less than half the photovoltaic voltage, the first controller U1 controls... When the fourth control transistor M4 is turned on, the first compensation capacitor CB1 stores energy. Simultaneously, the first controller U1 controls the first control transistor M1 and the first switching transistor V1 to turn on, while the first thyristor S1 is turned off. This connects the first compensation capacitor CB1 in series with the first capacitor C1 to compensate for the voltage of C1, maintaining it at half the photovoltaic voltage. When the voltage of C1 exceeds half the photovoltaic voltage, the first controller U1 only controls the first control transistor M1 and the first switching transistor V1 to turn on, forming a circuit between CB1 and C1 to store the energy in C1 and reduce its voltage. Similarly, when the voltage of the second capacitor C2 is less than or greater than half the photovoltaic voltage...By controlling the state of the second control transistor M2 or the third control transistor M3, the state of the second compensation capacitor CB2 is controlled, maintaining the voltage balance of the second capacitor C2, further maintaining the balance between the upper and lower capacitors, and improving the power conversion efficiency.

[0031] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0032] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A safety drive control circuit for a photovoltaic inverter, characterized in that, The circuit includes: Photovoltaic modules are used for photoelectric conversion and to provide photovoltaic power. A photovoltaic inverter module, connected to a photovoltaic module, is used to convert photovoltaic power into DC power. During the power conversion process, the photovoltaic power is shared by an upper capacitor and a lower capacitor, and the neutral point current between the upper and lower capacitors is controlled by injecting a common bias voltage, thereby actively controlling the voltage balance between the upper and lower capacitors. The compensation control module is connected to the photovoltaic module and the compensation capacitor module. It is used to stabilize the photovoltaic power and perform dual-path energy storage processing, and provide the first compensation power and the second compensation power respectively. When the voltage of the upper capacitor is less than half of the photovoltaic power voltage, the first compensation power is transmitted to the compensation capacitor module. When the voltage of the lower capacitor is less than half of the photovoltaic power voltage, the second compensation power is transmitted to the compensation capacitor module. The compensation capacitor module is connected to the photovoltaic inverter module. When the voltage of the upper capacitor is greater than half of the photovoltaic voltage, the first compensation capacitor stores the electrical energy released by the upper capacitor. When the voltage of the upper capacitor is less than half of the photovoltaic voltage, the first compensation energy is stored and the upper capacitor is compensated. When the voltage of the lower capacitor is greater than half of the photovoltaic voltage, the second compensation capacitor stores the electrical energy released by the lower capacitor. When the voltage of the lower capacitor is less than half of the photovoltaic voltage, the second compensation energy is stored and the lower capacitor is compensated. The microcontroller module connects to the photovoltaic module, photovoltaic inverter module, compensation control module, and compensation capacitor module. It controls the photovoltaic inverter module to perform photoelectric conversion, detects the voltage of the upper and lower capacitors, and changes the connection state between the compensation capacitor module and the photovoltaic inverter module when the voltage of the upper and lower capacitors is not equal to half of the photovoltaic voltage. Based on the magnitude of the voltage of the upper and lower capacitors and the photovoltaic voltage, it controls the compensation capacitor module to store the electrical energy released by the upper or lower capacitors, or controls the power transmission state of the compensation control module and the compensation state of the compensation capacitor module to the photovoltaic inverter module.

2. The photovoltaic inverter safety drive control circuit according to claim 1, characterized in that, The photovoltaic module includes a photovoltaic power supply and a third capacitor; the photovoltaic inverter module includes a first power transistor, a second power transistor, a third power transistor, a fourth power transistor, a fifth power transistor, a sixth power transistor, a seventh power transistor, an eighth power transistor, a first diode, a third diode, a fourth diode, a first inductor, an output port, a second diode, a first capacitor, and a second capacitor; the microcontroller module includes a first controller; The first terminal of the photovoltaic power supply is connected to the collector of the first power transistor, the positive terminal of the first capacitor, and the collector of the second power transistor. It is also connected via a third capacitor to the second terminal of the photovoltaic power supply, the emitter of the fourth power transistor, and the emitter of the eighth power transistor. The emitter of the first power transistor is connected to the collector of the third power transistor and the anode of the first diode. The emitter of the fifth power transistor is connected to the collector of the sixth power transistor and the cathode of the third diode. The anode of the third diode is connected to the cathode of the fourth diode, the anode of the first diode, the cathode of the second diode, the positive terminal of the second capacitor, and ground. The emitter of the third power transistor is connected to the anode of the second diode and the collector of the fourth power transistor. The anode of the diode is connected to the emitter of the seventh power transistor and the collector of the eighth power transistor. The emitter of the second power transistor is connected to the collector of the third power transistor and connected to one end of the output port through the first inductor. The emitter of the sixth power transistor is connected to the other end of the output port and the collector of the seventh power transistor. The gates of the first power transistor, the second power transistor, the third power transistor, the fourth power transistor, the fifth power transistor, the sixth power transistor, the seventh power transistor, and the eighth power transistor are respectively connected to the IO1, IO10, IO9, IO2, IO3, IO12, IO11, and IO4 terminals of the first controller.

3. The photovoltaic inverter safety drive control circuit according to claim 2, characterized in that, The compensation capacitor module includes a first control transistor, a first compensation capacitor, a fifth diode, a first switching transistor, a first thyristor, a first resistor, and a first voltage regulator. The source of the first control transistor is connected to the negative terminal of the first capacitor and one end of the first thyristor. The drain of the first control transistor is connected to the positive terminal of the first compensation capacitor. The gate of the first control transistor is connected to the anode of the fifth diode and the IO5 terminal of the first controller. The cathode of the fifth diode is connected to the base of the first switching transistor. The collector of the first switching transistor is connected to the control terminal of the first thyristor and connected to the first voltage regulator through the first resistor. The other end of the first thyristor is connected to the negative terminal of the first compensation capacitor, the emitter of the first switching transistor, the anode of the first diode, and ground.

4. The photovoltaic inverter safety drive control circuit according to claim 3, characterized in that, The compensation capacitor module also includes a second switching transistor, a second control transistor, a second thyristor, a sixth diode, a second compensation capacitor, and a second resistor; The collector of the second switching transistor is connected to the control terminal of the second switching transistor and connected to the first voltage regulator through the second resistor. One end of the second thyristor is connected to the source of the second control transistor and the negative terminal of the second capacitor. The other end of the second switching transistor is connected to the negative terminal of the second compensation capacitor and the emitter of the fourth power transistor. The drain of the second control transistor is connected to the positive terminal of the second compensation capacitor. The emitter of the second switching transistor is grounded. The gate of the second control transistor is connected to the IO6 terminal of the first controller and the anode of the sixth diode. The cathode of the sixth diode is connected to the base of the second switching transistor.

5. A photovoltaic inverter safety drive control circuit according to claim 4, characterized in that, The compensation control module includes a voltage regulator, a seventh diode, an eighth diode, a ninth diode, a first energy storage device, and a second energy storage device. The input terminal of the voltage regulator is connected to the first terminal of the photovoltaic power supply. The output terminal of the voltage regulator is connected to the anode of the seventh diode and the anode of the eighth diode. The cathode of the seventh diode is connected to the first terminal of the second energy storage device. The cathode of the eighth diode is connected to the first terminal of the first energy storage device. The second terminal of the second energy storage device is connected to the anode of the ninth diode, the negative terminal of the first compensation capacitor, and the ground terminal. The cathode of the ninth diode is connected to the second terminal of the first energy storage device, the ground terminal of the voltage regulator, the negative terminal of the second compensation capacitor, and the second terminal of the photovoltaic power supply.

6. A photovoltaic inverter safety drive control circuit according to claim 5, characterized in that, The compensation control module also includes a third control transistor and a tenth diode; The drain of the third control transistor is connected to the cathode of the eighth diode, the source of the third control transistor is connected to the anode of the tenth diode, the cathode of the tenth diode is connected to the positive terminal of the second compensation capacitor, and the gate of the third control transistor is connected to the IO7 terminal of the first controller.

7. A photovoltaic inverter safety drive control circuit according to claim 5, characterized in that, The compensation control module also includes a fourth control transistor and an eleventh diode; The drain of the fourth control transistor is connected to the cathode of the seventh diode, the source of the fourth control transistor is connected to the anode of the eleventh diode, the cathode of the eleventh diode is connected to the positive terminal of the first compensation capacitor, and the gate of the fourth control transistor is connected to the IO8 terminal of the first controller.

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