Grid-connected and off-grid safety control circuit for photovoltaic inverter

Abstract

The invention discloses a grid-connected and off-grid safety control circuit for a photovoltaic inverter, and relates to the technical field of photovoltaic grid-connected and off-grid, and the circuit comprises a photovoltaic adjustment module which is used for photovoltaic conversion and power adjustment; the photovoltaic detection module is used for performing low-voltage detection on the photovoltaic detection module; the temperature detection module is used for performing over-temperature detection; the intelligent control module is used for signal receiving and module control; the multi-level inversion module is used for carrying out energy storage boosting, self-voltage-sharing and inversion work and carrying out energy storage boosting and inversion work in cooperation with the inversion adjusting module; the adjustment switching module is used for controlling the working states of the multi-level inversion module and the inversion adjustment module; the inversion adjusting module is used for transmitting electric energy; the alternating-current power grid module is used for receiving electric energy and connected with an alternating-current power grid. According to the grid-connected and off-grid safety control circuit of the photovoltaic inverter, the voltage gain can be improved, the voltage distortion of the output end can be avoided, the electric energy loss and the working temperature of a switching tube element can be reduced in low voltage or over-temperature, and the safety of the circuit can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic grid-connected and off-grid technologies, and particularly to a photovoltaic inverter grid-connected and off-grid safety control circuit. Background Art

[0002] With the continuous improvement of renewable energy utilization technologies and the continuous expansion of the application scale, solar energy is transitioning from a supplementary energy source to an alternative energy source, and photovoltaic grid-connected and off-grid technologies are constantly developing. In order to improve the power conversion efficiency, the existing photovoltaic inverter grid-connected and off-grid safety control circuits generally adopt an inverter method, which is controlled by a relevant microcontroller to convert direct current into alternating current for conversion processing. At the connection between the photovoltaic inverter and the power grid, voltage fluctuations are likely to occur, resulting in abnormal grid connection and disconnection, reducing the power conversion efficiency. Moreover, when the photovoltaic power supply is low or the temperature rises, the loss of the switching tube is likely to increase, and even cause faults in the photovoltaic inverter, posing certain potential safety hazards. Therefore, improvement is needed. Summary of the Invention

[0003] An embodiment of the present invention provides a photovoltaic inverter grid-connected and off-grid safety control circuit to solve the problems raised in the above background art.

[0004] According to an embodiment of the present invention, a photovoltaic inverter grid-connected and off-grid safety control circuit is provided, including: a photovoltaic adjustment module, a photovoltaic detection module, a temperature detection module, an intelligent control module, a multilevel inversion module, an adjustment switching module, an inversion adjustment module, and an AC power grid module;

[0005] The photovoltaic adjustment module is connected to the intelligent control module and is used for performing optoelectronic conversion and outputting first electric energy, and when receiving a pulse signal output by the intelligent control module, performing power adjustment on the first electric energy and outputting second electric energy;

[0006] The photovoltaic detection module is connected to the photovoltaic adjustment module and is used for performing voltage sampling on the first electric energy and outputting a first control signal when the sampled signal is lower than a set voltage threshold;

[0007] The temperature detection module is connected to the photovoltaic adjustment module and is used for receiving the second electric energy and performing temperature detection, and outputting a second control signal when the sampled temperature signal is greater than a set over-temperature threshold;

[0008] The intelligent control module is connected to the photovoltaic adjustment module, the multilevel inversion module, the temperature detection module, the photovoltaic detection module, and the inversion adjustment module, and is used for outputting a pulse signal and controlling the photovoltaic adjustment module to perform power adjustment work, outputting a first inversion signal and controlling the multilevel inversion module to perform energy storage boost, self-voltage equalization, and inversion work, and when receiving the first control signal or the second control signal, outputting a second inversion signal and controlling the inversion adjustment module and the multilevel inversion module to perform energy storage boost and inversion work;

[0009] A multilevel inverter module, connected to the photovoltaic regulation module and the inverter regulation module, is configured to perform energy storage boost, self-equalizing voltage, and inverter operations on the input second electric energy when receiving a first inverter signal, and cooperate with the inverter regulation module to perform energy storage boost and inverter operations when receiving a second inverter signal, and output a first alternating current electric energy.

[0010] An adjustment switching module, connected to the temperature detection module, the photovoltaic regulation module, the multilevel inverter module, the inverter regulation module, and the photovoltaic detection module, is configured to receive the second electric energy and control the multilevel inverter module to work, and control the multilevel inverter module to cooperate with the inverter regulation module to start working when receiving a first control signal or a second control signal.

[0011] An inverter regulation module is configured to receive the electric energy transmitted by the multilevel inverter module and cooperate with the multilevel inverter module to perform energy storage boost and inverter operations when receiving a second inverter signal, and output a second alternating current electric energy.

[0012] An AC power grid module, connected to the multilevel inverter module and the inverter regulation module, is configured to transmit the first alternating current electric energy or the second alternating current electric energy to the connected AC power grid.

[0013] As a further solution of the present invention: the photovoltaic regulation module includes a photovoltaic power source, a first inductor, a first power transistor, a first capacitor, and a first diode; the intelligent control module includes a first controller.

[0014] Preferably, the first end of the photovoltaic power source is connected to the drain of the first power transistor and the anode of the first diode through the first inductor, the cathode of the first diode is connected to the temperature detection module, the adjustment switching module, and the multilevel inverter module and is connected to the source of the first power transistor, the second end of the photovoltaic power source, and the ground terminal through the first capacitor, and the gate of the first power transistor is connected to the IO1 terminal of the first controller.

[0015] As a further solution of the present invention: the multilevel inverter module includes a third power transistor, a second capacitor, a fourth power transistor, a fifth power transistor, a sixth power transistor, a seventh power transistor, a third capacitor, a ninth power transistor, a tenth power transistor, and a second inductor; the AC power grid module includes an AC power grid interface.

[0016] Preferably, the drain of the third power transistor is connected to the cathode of the first diode, the source of the third power transistor is connected to the drain of the fifth power transistor and is connected to the source of the fourth power transistor and the drain of the seventh power transistor through a second capacitor, the drain of the fourth power transistor is connected to the source of the fifth power transistor and is connected to the source of the seventh power transistor and the source of the ninth power transistor through a third capacitor, the drain of the ninth power transistor is connected to the source of the tenth power transistor and is connected to the first end of the AC grid interface through a second inductor, the second end of the AC grid interface is connected to the inverter regulation module, the source of the tenth power transistor is connected to the drain of the sixth power transistor, the drain of the sixth power transistor is connected to the second end of the photovoltaic power source, and the gates of the third power transistor, the fourth power transistor, the fifth power transistor, the sixth power transistor, the seventh power transistor, the ninth power transistor and the tenth power transistor are respectively connected to the IO3 terminal, IO4 terminal, IO5 terminal, IO6 terminal, IO7 terminal, IO9 terminal and IO10 terminal of the first controller.

[0017] As a further aspect of the present invention: the inverter regulation module includes a second power transistor and an eighth power transistor;

[0018] Preferably, the drain of the second power transistor is connected to the source of the eighth power transistor, the second end of the AC grid interface and the regulation switching module, the source of the second power transistor is connected to the source of the sixth power transistor, the drain of the eighth power transistor is connected to the source of the ninth power transistor, and the gates of the second power transistor and the eighth power transistor are respectively connected to the IO2 terminal and IO8 terminal of the first controller.

[0019] As a further aspect of the present invention: the regulation switching module includes a first resistor, a first thyristor, a second thyristor and a first switching transistor;

[0020] Preferably, the control terminal of the first thyristor is connected to the control terminal of the second thyristor and the collector of the first switching transistor and is connected to the anode of the first diode through a first resistor, one end of the first thyristor is connected to the drain of the second power transistor, the other end of the first thyristor is connected to the emitter of the first switching transistor and the second end of the photovoltaic power source, one end of the second thyristor is connected to the source of the third power transistor, the other end of the second thyristor is connected to the drain of the sixth power transistor, and the base of the first switching transistor is connected to the temperature detection module and the photovoltaic detection module.

[0021] As a further aspect of the present invention: the photovoltaic detection module includes a second resistor, a third resistor, a first comparator, a voltage threshold device and a second diode;

[0022] Preferably, one end of the second resistor is connected to the first end of the photovoltaic power supply, the inverting terminal of the first comparator is connected to the other end of the second resistor and connected to the second end of the photovoltaic power supply through the third resistor, the non-inverting terminal of the first comparator is connected to the voltage threshold device, the output terminal of the first comparator is connected to the IO11 terminal of the first controller and the anode of the second diode, and the cathode of the second diode is connected to the base of the first switching tube.

[0023] As a further solution of the present invention: The temperature detection module includes a first thermistor, a fourth resistor, a fifth resistor, a third diode and a fourth diode;

[0024] Preferably, one end of the first thermistor is connected to the cathode of the first diode, the other end of the first thermistor is connected to one end of the fifth resistor and connected to the second end of the photovoltaic power supply through the fourth resistor, the other end of the fifth resistor is connected to the cathode of the third diode, the anode of the third diode is connected to the anode of the fourth diode and the IO12 terminal of the first controller, and the cathode of the fourth diode is connected to the base of the first switching tube.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: The grid-connected and off-grid safety control circuit of the photovoltaic inverter of the present invention can control the multi-level inverter module through the intelligent control module to store energy, boost voltage, self-equalize voltage and invert the electric energy output by the photovoltaic regulation module. It can not only improve the voltage gain, but also avoid voltage distortion between the multi-level inverter module and the AC power grid module. At the same time, the photovoltaic detection module performs low-voltage detection on the photovoltaic regulation module, and the temperature detection module performs over-temperature detection. Then, when there is low voltage or over-temperature, the regulation switching module controls the inverter regulation module to cooperate with the multi-level inverter module to store energy, boost voltage and invert, ensuring energy storage, boosting voltage and inversion while reducing the power loss and working temperature of the switching tube components and improving the circuit safety. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0027] Figure 1 It is a schematic block diagram of the principle of a grid-connected and off-grid safety control circuit of a photovoltaic inverter provided by an embodiment of the present invention.

[0028] Figure 2 It is a circuit diagram of a grid-connected and off-grid safety control circuit of a photovoltaic inverter provided by an embodiment of the present invention.

[0029] Figure 3 It is a circuit diagram of the photovoltaic detection module provided by an embodiment of the present invention.

[0030] Figure 4 This is the circuit diagram of the temperature detection module provided by the embodiment of the present invention. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] In one embodiment, please refer to Figure 1 , a grid-connected and off-grid safety control circuit for a photovoltaic inverter, including: a photovoltaic regulation module 1, a photovoltaic detection module 2, a temperature detection module 3, an intelligent control module 4, a multilevel inverter module 5, a regulation switching module 6, an inverter regulation module 7, and an AC power grid module 8;

[0033] Specifically, the photovoltaic regulation module 1 is connected to the intelligent control module 4 and is used for performing photoelectric conversion and outputting a first electric energy. When receiving the pulse signal output by the intelligent control module 4, it performs power regulation on the first electric energy and outputs a second electric energy;

[0034] The photovoltaic detection module 2 is connected to the photovoltaic regulation module 1 and is used for sampling the voltage of the first electric energy and outputting a first control signal when the sampled signal is lower than the set voltage threshold;

[0035] The temperature detection module 3 is connected to the photovoltaic regulation module 1 and is used for receiving the second electric energy and performing temperature detection. When the sampled temperature signal is greater than the set over-temperature threshold, it outputs a second control signal;

[0036] The intelligent control module 4 is connected to the photovoltaic regulation module 1, the multilevel inverter module 5, the temperature detection module 3, the photovoltaic detection module 2, and the inverter regulation module 7, and is used for outputting a pulse signal and controlling the photovoltaic regulation module 1 to perform power regulation work, outputting a first inverter signal and controlling the multilevel inverter module 5 to perform energy storage boosting, self-equalizing voltage, and inverter work. When receiving the first control signal or the second control signal, it outputs a second inverter signal and controls the inverter regulation module 7 and the multilevel inverter module 5 to perform energy storage boosting and inverter work;

[0037] The multilevel inverter module 5 is connected to the photovoltaic regulation module 1 and the inverter regulation module 7, and is used for performing energy storage boosting, self-equalizing voltage, and inverter work on the input second electric energy when receiving the first inverter signal. When receiving the second inverter signal, it cooperates with the inverter regulation module 7 to perform energy storage boosting and inverter work and outputs a first AC electric energy;

[0038] The adjustment and switching module 6 is connected to the temperature detection module 3, the photovoltaic adjustment module 1, the multilevel inversion module 5, the inversion adjustment module 7, and the photovoltaic detection module 2, and is used to receive the second electric energy and control the multilevel inversion module 5 to work. When receiving the first control signal or the second control signal, it controls the multilevel inversion module 5 to cooperate with the inversion adjustment module 7 to start working;

[0039] The inversion adjustment module 7 is used to receive the electric energy transmitted by the multilevel inversion module when receiving the second inversion signal, and cooperate with the multilevel inversion module to perform energy storage boost and inversion work, and output the second alternating current electric energy;

[0040] The AC power grid module 8 is connected to the multilevel inversion module 5 and the inversion adjustment module 7, and is used to transmit the first alternating current electric energy or the second alternating current electric energy to the connected AC power grid.

[0041] In a specific embodiment, the above-mentioned photovoltaic adjustment module 1 can adopt a photovoltaic adjustment circuit composed of a photovoltaic power source, an inductor, a field effect transistor, etc., which can perform photoelectric conversion and perform power adjustment processing on the electric energy obtained from photoelectric conversion; the above-mentioned photovoltaic detection module 2 can adopt a photovoltaic detection circuit composed of a resistor, a comparator, a diode, etc., which can perform voltage sampling on the electric energy output by the photovoltaic adjustment module 1 and compare the set voltage threshold with the voltage magnitude of the sampled signal, and this voltage threshold is the minimum input voltage of the multilevel inversion module 5; the above-mentioned temperature detection module 3 can adopt a temperature detection circuit composed of a thermistor, a resistor, and a diode, which can perform temperature detection and provide a signal in a high-level state, that is, the second control signal, when the detected temperature signal is greater than the set temperature threshold; the above-mentioned intelligent control module 4 can adopt an intelligent control circuit composed of a single-chip microcomputer, which integrates many components such as an arithmetic unit, a controller, a memory, and an input / output unit, and realizes functions such as signal processing, data storage, module control, and timing control; the above-mentioned multilevel inversion module 5 can adopt a multilevel inversion circuit composed of a field effect transistor, a capacitor, and an inductor, and can perform energy storage boost, self-equalizing voltage, and inversion control on the input electric energy according to the conduction state of the field effect transistor; the above-mentioned adjustment and switching module 6 can adopt an adjustment and switching circuit composed of a thyristor, a resistor, and a triode, and can control the working states of the multilevel inversion module 5 and the inversion adjustment module 7 according to the transmission state of the control electric energy; the above-mentioned inversion adjustment module 7 can adopt an inversion adjustment circuit composed of a field effect transistor, control the transmission state of the electric energy, and cooperate with the multilevel inversion module 5 to perform energy storage boost, self-equalizing voltage, and inversion control; the above-mentioned AC power grid module 8 can adopt an AC power grid circuit composed of an AC power grid interface, be connected to the AC power grid, and realize safe parallel and off-grid control with the multilevel inversion module 5.

[0042] In another embodiment, please refer to Figure 1 、 Figure 2 、 Figure 3 andFigure 4 , the photovoltaic regulation module 1 includes a photovoltaic power source, a first inductor L1, a first power transistor Q1, a first capacitor L1, and a first diode D1; the intelligent control module 4 includes a first controller U1;

[0043] Specifically, the first terminal of the photovoltaic power source is connected to the drain of the first power transistor Q1 and the anode of the first diode D1 through the first inductor L1. The cathode of the first diode D1 is connected to the temperature detection module 3, the regulation switching module 6, and the multilevel inversion module 5, and is connected to the source of the first power transistor Q1, the second terminal of the photovoltaic power source, and the ground terminal through the first capacitor L1. The gate of the first power transistor Q1 is connected to the IO1 terminal of the first controller U1.

[0044] In a specific embodiment, the above-mentioned first power transistor Q1 can be an N-channel field effect transistor, which cooperates with the first diode D1, the first inductor L1, and the first capacitor L1 for power regulation; the above-mentioned first controller U1 can be an STM32 single-chip microcomputer.

[0045] Furthermore, the multilevel inversion module 5 includes a third power transistor Q3, a second capacitor C2, a fourth power transistor Q4, a fifth power transistor Q5, a sixth power transistor Q6, a seventh power transistor Q7, a third capacitor C3, a ninth power transistor Q9, a tenth power transistor Q10, and a second inductor L2; the AC power grid module 8 includes an AC power grid interface;

[0046] Specifically, the drain of the third power transistor Q3 is connected to the cathode of the first diode D1. The source of the third power transistor Q3 is connected to the drain of the fifth power transistor Q5 and is connected to the source of the fourth power transistor Q4 and the drain of the seventh power transistor Q7 through the second capacitor C2. The drain of the fourth power transistor Q4 is connected to the source of the fifth power transistor Q5 and is connected to the source of the seventh power transistor Q7 and the source of the ninth power transistor Q9 through the third capacitor C3. The drain of the ninth power transistor Q9 is connected to the source of the tenth power transistor Q10 and is connected to the first terminal of the AC power grid interface through the second inductor L2. The second terminal of the AC power grid interface is connected to the inversion regulation module 7. The source of the tenth power transistor Q10 is connected to the drain of the sixth power transistor Q6. The drain of the sixth power transistor Q6 is connected to the second terminal of the photovoltaic power source. The gates of 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, the ninth power transistor Q9, and the tenth power transistor Q10 are respectively connected to the IO3 terminal, IO4 terminal, IO5 terminal, IO6 terminal, IO7 terminal, IO9 terminal, and IO10 terminal of the first controller U1.

[0047] In a specific embodiment, the above-mentioned third power transistor Q3, fourth power transistor Q4, fifth power transistor Q5, sixth power transistor Q6, seventh power transistor Q7, ninth power transistor Q9, and tenth power transistor Q10 can all be selected as N-channel field effect transistors, and are all controlled by the first inverter signal output by the first controller U1. Moreover, the third power transistor Q3, second power transistor Q2, eighth power transistor Q8, and sixth power transistor Q6 can also be controlled by the second inverter signal output by the first controller U1.

[0048] Further, the inverter adjustment module 7 includes a second power transistor Q2 and an eighth power transistor Q8;

[0049] Specifically, the drain of the second power transistor Q2 is connected to the source of the eighth power transistor Q8, the second terminal of the AC power grid interface, and the adjustment switching module 6. The source of the second power transistor Q2 is connected to the source of the sixth power transistor Q6. The drain of the eighth power transistor Q8 is connected to the source of the ninth power transistor Q9. The gates of the second power transistor Q2 and the eighth power transistor Q8 are respectively connected to the IO2 terminal and the IO8 terminal of the first controller U1.

[0050] In a specific embodiment, the above-mentioned second power transistor Q2 and eighth power transistor Q8 can both be selected as N-channel field effect transistors and are controlled by the second inverter signal.

[0051] Further, the adjustment switching module 6 includes a first resistor R1, a first thyristor S1, a second thyristor S2, and a first switching transistor V1;

[0052] Specifically, the control terminal of the first thyristor S1 is connected to the control terminal of the second thyristor S2 and the collector of the first switching transistor V1, and is connected to the anode of the first diode D1 through the first resistor R1. One end of the first thyristor S1 is connected to the drain of the second power transistor Q2. The other end of the first thyristor S1 is connected to the emitter of the first switching transistor V1 and the second terminal of the photovoltaic power supply. One end of the second thyristor S2 is connected to the source of the third power transistor Q3. The other end of the second thyristor S2 is connected to the drain of the sixth power transistor Q6. The base of the first switching transistor V1 is connected to the temperature detection module 3 and the photovoltaic detection module 2.

[0053] In a specific embodiment, the above-mentioned first thyristor S1 and second thyristor S2 can both be selected as bidirectional thyristors; the above-mentioned first switching transistor V1 can be selected as an NPN type triode.

[0054] Further, the photovoltaic detection module 2 includes a second resistor R2, a third resistor R3, a first comparator A1, a voltage threshold device, and a second diode D2;

[0055] Specifically, one end of the second resistor R2 is connected to the first end of the photovoltaic power source. The inverting input terminal of the first comparator A1 is connected to the other end of the second resistor R2 and is connected to the second end of the photovoltaic power source through the third resistor R3. The non-inverting input terminal of the first comparator A1 is connected to the voltage threshold device. The output terminal of the first comparator A1 is connected to the IO11 terminal of the first controller U1 and the anode of the second diode D2. The cathode of the second diode D2 is connected to the base of the first switching transistor V1.

[0056] In a specific embodiment, the above-mentioned second resistor R2 and third resistor R3 perform voltage sampling; the above-mentioned first comparator A1 can be selected as an LM358 comparator; the above-mentioned voltage threshold device can be composed of a reference power source and a resistor to provide a voltage threshold.

[0057] Further, the temperature detection module 3 includes a first thermistor RT1, a fourth resistor R4, a fifth resistor R5, a third diode D3, and a fourth diode D4;

[0058] Specifically, one end of the first thermistor RT1 is connected to the cathode of the first diode D1. The other end of the first thermistor RT1 is connected to one end of the fifth resistor R5 and is connected to the second end of the photovoltaic power source through the fourth resistor R4. The other end of the fifth resistor R5 is connected to the cathode of the third diode D3. The anode of the third diode D3 is connected to the anode of the fourth diode D4 and the IO12 terminal of the first controller U1. The cathode of the fourth diode D4 is connected to the base of the first switching transistor V1.

[0059] In a specific embodiment, the above-mentioned first thermistor RT1 can be selected as a negative temperature coefficient thermistor; the above-mentioned fifth resistor R5 and third diode D3 set an over-temperature threshold, and when over-temperature occurs, the third diode D3 is broken down.

[0060] In a photovoltaic inverter grid-connected and off-grid safety control circuit of this embodiment, a photovoltaic power source performs photoelectric conversion and outputs first electric energy. The IO1 terminal of the first controller U1 outputs a pulse signal to control the conduction state of the first power transistor Q1. In cooperation with the first inductor L1, the first diode D1, and the first capacitor L1, power regulation is performed and second electric energy is output. The first controller U1 outputs a first inversion signal to control the multilevel inversion module 5 to perform energy storage boost, self-equalizing voltage, and inversion operations on the second electric energy, and then outputs first alternating current electric energy. Specifically, the IO3 terminal and the IO10 terminal of the first controller U1 output the first inversion signal to control a loop formed by the third power transistor Q3, the tenth power transistor Q10, the second inductor L2, the first thyristor S1, the AC grid interface, the second thyristor S2, and the first capacitor L1. The first electric energy is regulated by the third power transistor Q3 and the tenth power transistor Q10 and then transmitted to the AC grid connected to the first end of the AC grid interface through the second inductor L2. Then, the IO3 terminal, the IO7 terminal, the IO5 terminal, and the IO9 terminal of the first controller U1 all output the first inversion signal to control a loop formed by the third power transistor Q3, the second capacitor C2, the seventh power transistor Q7, the fifth power transistor Q5, the third capacitor C3, the ninth power transistor Q9, the second inductor L2, the first thyristor S1, the AC grid interface, and the first capacitor L1. Among them, the second capacitor C2 and the third capacitor C3 perform parallel energy storage and self-equalizing voltage control and supply power to the first end of the AC grid interface at the same time. Then, the IO3 terminal, the IO4 terminal, and the IO9 terminal of the first controller U1 output the first inversion signal to control a loop formed by the third power transistor Q3, the fourth power transistor Q4, the second capacitor C2, the third capacitor C3, the ninth power transistor Q9, the second inductor L2, the AC grid interface, the first thyristor S1, and the first capacitor L1. Among them, the second capacitor C2 and the third capacitor C3 are connected in series to supply power, increasing the voltage gain and supplying power to the first end of the AC grid interface. Then, the IO6 terminal and the IO10 terminal of the first controller U1 output the first inversion signal to control a loop formed by the sixth power transistor Q6, the tenth power transistor Q10, the second inductor L2, the first thyristor S1, and the AC grid interface and supply power to the first end of the AC grid interface. Then, the IO6 terminal, the IO9 terminal, the IO5 terminal, and the IO7 terminal of the first controller U1 output the first inversion signal to control a loop formed by the sixth power transistor Q6, the ninth power transistor Q9, the fifth power transistor Q5, the seventh power transistor Q7, the second capacitor C2, the third capacitor C3, the second inductor L2, the first thyristor S1, the second thyristor S2, and the AC grid interface. Among them, the second capacitor C2 and the third capacitor C3 perform parallel energy storage and self-equalizing voltage control and supply power to the second end of the AC grid interface at the same time. Finally, the IO6 terminal, the IO9 terminal, and the IO4 terminal of the first controller U1 control a loop formed by the sixth power transistor Q6, the ninth power transistor Q9, the fourth power transistor Q4, the second capacitor C2, the third capacitor C3, the second inductor L2, the first thyristor S1, the second thyristor S2, and the AC grid interface.Control the second capacitor C2 and the third capacitor C3 to discharge in series and supply power to the second end of the AC grid interface, completing one cycle of the inverter operation, avoiding the situation of output voltage fluctuation when paralleling and disconnecting from the AC grid. At the same time, the second resistor R2 and the third resistor R3 sample the voltage of the photovoltaic power supply. When the sampled signal is lower than the voltage threshold set by the voltage threshold device, the first comparator A1 outputs a first control signal to control the first switch tube V1 to conduct and is received by the IO11 terminal interface of the first controller U1. The first thermistor RT1 and the fourth resistor R4 detect the temperature. When the detected temperature is greater than the over-temperature threshold set by the fifth resistor R5 and the third diode D3, the third diode D3 is broken down, outputting a second control signal to control the first switch tube V1 to conduct and is received by the IO12 terminal of the first controller U1, so that in the low-voltage or over-temperature state, the first thyristor S1 and the second thyristor S2 are cut off. The IO3 terminal and the IO2 terminal of the first controller U1 output a second inverter signal to control the third power tube Q3 and the second power tube Q2 to conduct, cooperate with the second capacitor C2 and the third capacitor C3 for series boost regulation, and supply power to the first end of the AC grid interface. Then, the IO3 terminal, the IO8 terminal and the IO6 terminal of the first controller U1 output a second inverter signal, cooperate with the second capacitor C2 and the third capacitor C3 for series boost regulation and supply power to the second end of the AC grid interface, completing the inversion and maintaining the power supply state with the AC grid, reducing the power consumption of the first controller U1 and the field effect transistor, and reducing the power consumption and the circuit temperature.

[0061] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0062] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard 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 photovoltaic inverter on-grid and off-grid safety control circuit, characterized in that: The photovoltaic inverter on-grid and off-grid safety control circuit includes: a photovoltaic regulation module, a photovoltaic detection module, a temperature detection module, an intelligent control module, a multi-level inverter module, a regulation switching module, an inverter regulation module and an AC power grid module; The photovoltaic regulation module is connected to the intelligent control module, and is used to perform photoelectric conversion and output the first electric energy. When receiving the pulse signal output by the intelligent control module, the photovoltaic regulation module performs power regulation on the first electric energy and outputs the second electric energy. The photovoltaic detection module is connected to the photovoltaic regulation module and is used to perform voltage sampling on the first electric energy and output a first control signal when the sampled signal is lower than a set voltage threshold; The temperature detection module is connected to the photovoltaic regulation module, and is used to receive the second electric energy and perform temperature detection, and output a second control signal when the sampled temperature signal is greater than a set over-temperature threshold; The intelligent control module is connected to the photovoltaic regulation module, the multi-level inverter module, the temperature detection module, the photovoltaic detection module and the inverter regulation module, and is used to output a pulse signal and control the photovoltaic regulation module to perform power regulation, output a first inverter signal and control the multi-level inverter module to perform energy storage boosting, self-balanced voltage and inverter operations, and when receiving the first control signal or the second control signal, output a second inverter signal and control the inverter regulation module and the multi-level inverter module to perform energy storage boosting and inverter operations; The multi-level inverter module is connected to the photovoltaic regulation module and the inverter regulation module, and is used to perform energy storage, voltage boosting, self-voltage balancing and inversion operations on the input second electric energy when receiving the first inversion signal, and cooperate with the inversion regulation module to perform energy storage, voltage boosting and inversion operations when receiving the second inversion signal, and output the first AC electric energy; The regulation switching module is connected to the temperature detection module, the photovoltaic regulation module, the multi-level inverter module, the inverter regulation module and the photovoltaic detection module, and is used to receive the second electric energy and control the multi-level inverter module to work, and when receiving the first control signal or the second control signal, controls the multi-level inverter module to cooperate with the inverter regulation module to start working; The inverter regulation module is used to receive the electric energy transmitted by the multi-channel level inverter module and cooperate with the multi-channel level inverter module to perform energy storage, voltage boosting and inversion work, and output the second AC electric energy when receiving the second inverter signal; The AC power grid module is connected to the multi-level inverter module and the inverter regulation module, and is used to transmit the first AC power energy or the second AC power energy to the connected AC power grid.

2. A photovoltaic inverter on-grid and off-grid safety control circuit according to claim 1, characterized in that: The photovoltaic regulation module includes a photovoltaic power source, a first inductor, a first power tube, a first capacitor and a first diode; the intelligent control module includes a first controller; The first end of the photovoltaic power supply is connected to the drain of the first power tube and the anode of the first diode through the first inductor, the cathode of the first diode is connected to the temperature detection module, the regulation switching module and the multi-level inverter module, and is connected to the source of the first power tube, the second end of the photovoltaic power supply and the ground through the first capacitor, and the gate of the first power tube is connected to the IO1 end of the first controller.

3. A photovoltaic inverter on-grid and off-grid safety control circuit according to claim 2, characterized in that: The multi-level inverter module includes a third power tube, a second capacitor, a fourth power tube, a fifth power tube, a sixth power tube, a seventh power tube, a third capacitor, a ninth power tube, a tenth power tube and a second inductor; the AC power grid module includes an AC power grid interface; The drain of the third power tube is connected to the cathode of the first diode, the source of the third power tube is connected to the drain of the fifth power tube and is connected to the source of the fourth power tube and the drain of the seventh power tube through the second capacitor, the drain of the fourth power tube is connected to the source of the fifth power tube and is connected to the source of the seventh power tube and the source of the ninth power tube through the third capacitor, the drain of the ninth power tube is connected to the source of the tenth power tube and is connected to the first end of the AC power grid interface through the second inductor, the second end of the AC power grid interface is connected to the inverter regulation module, the source of the tenth power tube is connected to the drain of the sixth power tube, the drain of the sixth power tube is connected to the second end of the photovoltaic power supply, and the gate of the third power tube, the gate of the fourth power tube, the gate of the fifth power tube, the gate of the sixth power tube, the gate of the seventh power tube, the gate of the ninth power tube and the gate of the tenth power tube are respectively connected to the IO3 end, the IO4 end, the IO5 end, the IO6 end, the IO7 end, the IO9 end and the IO10 end of the first controller.

4. A photovoltaic inverter on-grid and off-grid safety control circuit according to claim 3, characterized in that: The inverter regulation module includes a second power tube and an eighth power tube; The drain of the second power tube is connected to the source of the eighth power tube, the second end of the AC power grid interface and the regulation switching module, the source of the second power tube is connected to the source of the sixth power tube, the drain of the eighth power tube is connected to the source of the ninth power tube, and the gate of the second power tube and the gate of the eighth power tube are respectively connected to the IO2 end and IO8 end of the first controller.

5. A photovoltaic inverter on-grid and off-grid safety control circuit according to claim 4, characterized in that: The regulating switching module includes a first resistor, a first thyristor, a second thyristor and a first switch tube; The control end of the first thyristor is connected to the control end of the second thyristor and the collector of the first switch tube and is connected to the anode of the first diode through the first resistor, one end of the first thyristor is connected to the drain of the second power tube, the other end of the first thyristor is connected to the emitter of the first switch tube and the second end of the photovoltaic power supply, one end of the second thyristor is connected to the source of the third power tube, the other end of the second thyristor is connected to the drain of the sixth power tube, and the base of the first switch tube is connected to the temperature detection module and the photovoltaic detection module.

6. A photovoltaic inverter on-grid and off-grid safety control circuit according to claim 5, characterized in that: The photovoltaic detection module includes a second resistor, a third resistor, a first comparator, a voltage threshold device, and a second diode; One end of the second resistor is connected to the first end of the photovoltaic power supply, the inverting end of the first comparator is connected to the other end of the second resistor and is connected to the second end of the photovoltaic power supply through the third resistor, the non-inverting end of the first comparator is connected to the voltage threshold device, the output end of the first comparator is connected to the IO11 end of the first controller and the anode of the second diode, and the cathode of the second diode is connected to the base of the first switch tube.

7. A photovoltaic inverter on-grid and off-grid safety control circuit according to claim 5, characterized in that: The temperature detection module includes a first thermistor, a fourth resistor, a fifth resistor, a third diode and a fourth diode; One end of the first thermistor is connected to the cathode of the first diode, the other end of the first thermistor is connected to one end of the fifth resistor and connected to the second end of the photovoltaic power supply through the fourth resistor, the other end of the fifth resistor is connected to the cathode of the third diode, the anode of the third diode is connected to the anode of the fourth diode and the IO12 terminal of the first controller, and the cathode of the fourth diode is connected to the base of the first switch tube.

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