A fast transient overcurrent suppression circuit for a photovoltaic inverter and a photovoltaic power generation system

Abstract

This application relates to a fast transient overcurrent suppression circuit for a photovoltaic inverter and a photovoltaic power generation system. The fast transient overcurrent suppression circuit for the photovoltaic inverter, based on FPGA logic operation circuitry, outputs a blocking signal when the measured electrical signal output from the AC side of the inverter module exceeds a preset electrical signal threshold, thereby shutting off multiple power switching devices in the inverter module. This prevents transient overcurrent from burning out these power switching devices, reduces inverter module maintenance, and improves the inverter module's lifespan and reliability. When the measured electrical signal output from the AC side of the inverter module is less than or equal to the preset electrical signal threshold, a trigger signal is output to trigger a digital signal processing circuit to output a modulated wave signal, turning on multiple power switching devices in the inverter module, thereby ensuring the normal operation of the inverter module.

Description

Technical Field

[0001] This application relates to the field of overcurrent suppression technology, and in particular to a fast transient overcurrent suppression circuit for a photovoltaic inverter and a photovoltaic power generation system. Background Technology

[0002] In a photovoltaic (PV) power generation system, the inverter is responsible for converting the direct current (DC) generated by the PV modules into alternating current (AC), which is then fed into the grid or output to the load. During operation, the inverter may generate transient overcurrents due to load fluctuations, grid disturbances, short-circuit faults, or other reasons. If these transient overcurrents are not suppressed in time, they can damage power switching devices such as IGBTs (Insulated Gate Bipolar Transistors) and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), and may even lead to system shutdown, affecting power generation efficiency and equipment safety.

[0003] In traditional technologies, DSPs (Digital Signal Processing) are often used as the control core. However, DSPs have limited sampling rates and cannot achieve fast response. Therefore, when a transient overcurrent is detected, the power device's tolerance time has often exceeded the threshold, leading to device burnout. Summary of the Invention

[0004] Therefore, it is necessary to provide a fast transient overcurrent suppression circuit for photovoltaic inverters and a photovoltaic power generation system that can detect transient overcurrents in a timely manner.

[0005] In a first aspect, a fast transient overcurrent suppression circuit for a photovoltaic inverter is provided, comprising:

[0006] The sampling circuit has its input terminal connected to the AC side of the inverter module and is used to acquire the electrical signal to be measured output from the AC side of the inverter module.

[0007] The logic operation circuit has its input connected to the output of the sampling circuit. The logic operation circuit is used to receive the electrical signal to be tested and outputs a blocking signal when the electrical signal to be tested is greater than a preset electrical signal threshold, and outputs a trigger signal when the electrical signal to be tested is less than or equal to the preset electrical signal threshold. The logic operation circuit is an FPGA circuit.

[0008] The digital signal processing circuit has its input terminal connected to the first output terminal of the logic operation circuit; the digital signal processing circuit is used to receive and output a modulated wave signal based on the trigger signal.

[0009] The driving circuit has a first input terminal connected to the second output terminal of the logic operation circuit, a second input terminal connected to the output terminal of the digital signal processing circuit, and an output terminal connected to the control terminal of multiple power switching devices in the inverter module. The driving circuit is used to turn off multiple power switching devices when a blocking signal is received, and to turn on multiple power switching devices when a modulated wave signal is received.

[0010] In one embodiment, the logic circuitry is further used for:

[0011] Record and store multiple electrical signals to be tested, so as to obtain current waveform data based on multiple electrical signals to be tested;

[0012] When the electrical signal under test is greater than the preset electrical signal threshold, the overcurrent data under overcurrent conditions is output; the overcurrent data includes current waveform data.

[0013] In one embodiment, the digital signal processing circuitry is also used to receive and determine the overcurrent type based on the current waveform data.

[0014] In one embodiment, the digital signal processing circuit is further configured to generate a control signal to the drive circuit according to the overcurrent type, so that the drive circuit executes the fault handling strategy corresponding to the overcurrent type.

[0015] In one embodiment, after receiving the electrical signal to be tested and before outputting a blocking signal or a trigger signal, the logic operation circuit is further configured to:

[0016] The electrical signal to be tested is preprocessed to obtain the preprocessed electrical signal to be tested.

[0017] In one embodiment, the preprocessing includes noise reduction.

[0018] In one embodiment, the sampling circuit is used for:

[0019] Acquire analog electrical signals from the AC side of the inverter module;

[0020] Convert analog electrical signals into digital alternating current signals.

[0021] Secondly, a photovoltaic power generation system is also provided, including:

[0022] Inverter module; the DC side of the inverter module is used to connect to the output terminal of the photovoltaic array.

[0023] The grid-connected relay has its input terminal connected to the AC side of the inverter module, and its output terminal used to connect to the load.

[0024] As described above, the fast transient overcurrent suppression circuit of the photovoltaic inverter has its input terminal connected to the AC side of the inverter module, and its output terminal connected to the control terminals of multiple power switching devices in the inverter module.

[0025] In one embodiment, the photovoltaic power generation system further includes:

[0026] The filter circuit has its input connected to the AC side of the inverter module and its output connected to the input of the grid-connected relay.

[0027] In one embodiment, the photovoltaic power generation system further includes:

[0028] The DC bus capacitor is connected in parallel between the positive and negative terminals of the DC bus of each inverter in the inverter module.

[0029] The aforementioned fast transient overcurrent suppression circuit and photovoltaic power generation system of the photovoltaic inverter, based on the logic operation circuit of the FPGA, can output a blocking signal when the measured electrical signal output from the AC side of the inverter module exceeds a preset electrical signal threshold, thereby shutting down multiple power switching devices in the inverter module. This prevents transient overcurrent from burning out these power switching devices, reduces the maintenance and repair of the inverter module, and improves the service life and reliability of the inverter module. When the measured electrical signal output from the AC side of the inverter module is less than or equal to the preset electrical signal threshold, a trigger signal is output to trigger the digital signal processing circuit to output a modulated wave signal, turning on multiple power switching devices in the inverter module, thereby ensuring the normal operation of the inverter module. Compared with traditional technologies, in the fast transient overcurrent suppression circuit of this photovoltaic inverter, the overcurrent protection function is moved from the software processing level of the digital signal processing circuit to the hardware logic level of the FPGA. Therefore, the fast transient overcurrent suppression circuit of this photovoltaic inverter can achieve nanosecond-level overcurrent detection and microsecond-level PWM blocking at the hardware level. This solves the problem of traditional single DSP architecture's inability to quickly and effectively suppress transient overcurrents due to software interrupt response delays, thus improving the timeliness of transient overcurrent suppression. The aforementioned transient overcurrent suppression circuit, while retaining the processing power and configurability of digital signal processing circuits for complex control algorithms, achieves faster and more reliable overcurrent protection based on FPGA, fully leveraging the advantages of FPGA hardware parallel processing. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a block diagram of a fast transient overcurrent suppression circuit for a photovoltaic inverter according to one embodiment;

[0032] Figure 2 This is a structural block diagram of a photovoltaic power generation system according to one embodiment. Detailed Implementation

[0033] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0035] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0036] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0037] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0038] In existing photovoltaic inverters, a single DSP is often used as the control core. This DSP has a built-in ADC (Analog-to-Digital Converter Sampling) module. The ADC module can sample the current signal, and based on this current signal, after processing by software algorithms, output a PWM (Pulse Width Modulation) pulse signal to control the power switching devices in the inverter. However, the sampling rate of this DSP is limited by the ADC conversion time and the software interrupt response time, and the sampling speed of this DSP is usually on the order of tens of microseconds. However, for transient overcurrents such as short-circuit currents with rise times of up to microseconds, the DSP has difficulty achieving a fast response. Therefore, when the software detects a transient overcurrent, it has often exceeded the withstand time of the power switching devices, resulting in the burnout of the power switching devices.

[0039] In existing technologies, some solutions use hardware comparators to directly block the PWM in order to improve the speed of overcurrent protection. Although this method has a fast response, it lacks flexibility and cannot predict or control the current wave according to the trend of current change, making it difficult to meet the protection requirements under complex operating conditions.

[0040] In a specific embodiment, such as Figure 1 As shown, a fast transient overcurrent suppression circuit 10 for a photovoltaic inverter is provided, including: a sampling circuit 102, a logic operation circuit 104, a digital signal processing circuit 106, and a drive circuit 108.

[0041] The input terminal of the sampling circuit 102 is used to connect to the AC side of the inverter module 20, and the sampling circuit 102 is used to collect the electrical signal to be measured output from the AC side of the inverter module 20.

[0042] The input terminal of the logic operation circuit 104 is connected to the output terminal of the sampling circuit 102. The logic operation circuit 104 is used to receive the electrical signal to be tested, and output a blocking signal when the electrical signal to be tested is greater than a preset electrical signal threshold, and output a trigger signal when the electrical signal to be tested is less than or equal to the preset electrical signal threshold. The logic operation circuit 104 is an FPGA (Field-Programmable Gate Array) circuit.

[0043] The input terminal of the digital signal processing circuit 106 is connected to the first output terminal of the logic operation circuit 104; the digital signal processing circuit 106 is used to receive and output a modulated wave signal based on the trigger signal. The communication between the logic operation circuit 104 and the digital signal processing circuit 106 is parallel communication. Both the blocking signal and the modulated wave signal can be PWM signals.

[0044] The first input terminal of the drive circuit 108 is connected to the second output terminal of the logic operation circuit 104, the second input terminal of the drive circuit 108 is connected to the output terminal of the digital signal processing circuit 106, and the output terminal of the drive circuit 108 is used to connect to the control terminal of multiple power switching devices in the inverter module 20. The drive circuit 108 is used to turn off multiple power switching devices when a blocking signal is received, and also to turn on multiple power switching devices when a modulated wave signal is received.

[0045] FPGAs have the advantage of parallel processing. Real-time acquisition of the electrical signal under test, comparison of the electrical signal under test with the preset electrical signal threshold, and PWM blocking can all be completed in hardware logic without waiting for software interrupt response and program execution. This allows the total delay time between detecting transient overcurrent (i.e., the electrical signal under test is greater than the preset electrical signal threshold) and driving the shutdown of multiple power switching devices to be controlled in the nanosecond to microsecond range, which is much faster than the tens of microsecond range of traditional DSP-based technologies. Thus, effective transient overcurrent suppression can be achieved within the tolerance time of multiple power switching devices, avoiding the burnout of these power switching devices.

[0046] The sampling circuit 102 can acquire the electrical signal under test output from the AC side of the inverter module 20 in real time. The logic operation circuit 104 may include a parallel comparator array of multiple FPAGs. The current data stream of multiple electrical signals under test is transmitted to the parallel comparator array, and the parallel comparator array compares the multiple electrical signals under test with preset electrical signal thresholds point by point.

[0047] The blocking signal has the highest priority. Therefore, when the logic circuit 104 outputs the blocking signal, all remaining pulses in the current PWM cycle can be immediately cut off, forcibly shutting down multiple power switching devices. This avoids the need to wait for the end of a PWM cycle in traditional technology before software can determine and adjust the pulses for the next cycle, achieving true wave-by-wave current limiting and precise protection within the PWM cycle. Thus, the highest priority blocking signal effectively suppresses transient overcurrents and prevents shutdowns of the photovoltaic power generation system caused by multiple consecutive blocking cycles, improving the continuous operation capability of the photovoltaic power generation system equipped with the fast transient overcurrent suppression circuit 10 of this photovoltaic inverter under disturbances.

[0048] Therefore, the fast transient overcurrent suppression circuit 10 of the aforementioned photovoltaic inverter, based on the logic operation circuit 104 of the FPGA, can output a blocking signal when the measured electrical signal output from the AC side of the inverter module 20 is greater than a preset electrical signal threshold, thereby shutting down multiple power switching devices in the inverter module 20. This prevents transient overcurrent from burning out these power switching devices, reduces the maintenance of the inverter module 20, and improves the service life and reliability of the inverter module 20. When the measured electrical signal output from the AC side of the inverter module 20 is less than or equal to the preset electrical signal threshold, it outputs a trigger signal to trigger the digital signal processing circuit 106 to output a modulated wave signal, turning on multiple power switching devices in the inverter module 20, thereby ensuring the normal operation of the inverter module 20. Compared with traditional technologies, in the fast transient overcurrent suppression circuit 10 of this photovoltaic inverter, the overcurrent protection function is moved from the software processing level of the digital signal processing circuit 106 to the hardware logic level of the FPGA. Therefore, the fast transient overcurrent suppression circuit 10 of this photovoltaic inverter can achieve nanosecond-level overcurrent detection and microsecond-level PWM blocking at the hardware level. This solves the problem of the inability to quickly detect transient overcurrents due to software interrupt response delays in traditional single-DSP architectures, thus improving the timeliness of transient overcurrent suppression. The aforementioned transient overcurrent suppression circuit, while retaining the processing capability and configurability of the digital signal processing circuit 106 for complex control algorithms, achieves faster and more reliable overcurrent protection based on FPGA, fully leveraging the advantages of FPGA hardware parallel processing.

[0049] Furthermore, the FPGA-structured logic operation circuit 104 has high scalability, enabling the protection algorithm to be expanded through online upgrades without changing the hardware design. Therefore, the fast transient overcurrent suppression circuit 10 of this photovoltaic inverter also possesses high expansion flexibility and configurability, meeting upgrade requirements under different operating conditions. The preset electrical signal threshold can be dynamically configured by the digital signal processing circuit 106 according to the usage environment to adapt to differentiated protection needs of different power grid environments, load types, and power levels. The protection algorithm includes inverse time protection and di / dt warning. The di / dt warning is a current change rate warning; di / dt is the first derivative of current with respect to time, representing the rate of current change.

[0050] Furthermore, in the aforementioned fast transient overcurrent suppression circuit 10 of the photovoltaic inverter, the FPGA-based hardware overcurrent suppression logic operates independently of the digital signal processing circuit 106. Therefore, even if the digital signal processing circuit 106 experiences a system crash, program failure, or software malfunction, the logic operation circuit 104 can still reliably suppress overcurrent to ensure the safety of multiple power switching devices. The separation of hardware-level protection and software control in the fast transient overcurrent suppression circuit 10 of the photovoltaic inverter significantly improves the circuit's fault tolerance and reliability.

[0051] In one specific embodiment, the logic operation circuit 104 is also used for:

[0052] Record and store multiple electrical signals to be tested, so as to obtain current waveform data based on multiple electrical signals to be tested.

[0053] When the electrical signal under test is greater than the preset electrical signal threshold, the overcurrent data under overcurrent conditions is output; the overcurrent data includes current waveform data.

[0054] The frequency at which the logic operation circuit 104 reads the electrical signal under test is much higher than the sampling frequency of a traditional DSP. For example, the reading frequency of the logic operation circuit 104 can be in the frequency range of 100kHz to 200kHz. Of course, the actual value of the reading frequency of the logic operation circuit 104 also depends on the actual requirements of the fast transient overcurrent suppression circuit 10 of the photovoltaic inverter and the sampling frequency of the sampling circuit 102.

[0055] The output current waveform data includes at least the current waveform at the moment of overcurrent, and may also include the current waveform before the moment of overcurrent. Therefore, operators can analyze the operating conditions before the overcurrent occurred and the causes of the overcurrent based on the current waveform data.

[0056] In one embodiment, the overcurrent data also includes an overcurrent fault flag, an overcurrent timestamp, and an overcurrent peak current value.

[0057] In one specific embodiment, the digital signal processing circuit 106 is further configured to receive and determine the overcurrent type based on the current waveform data. The overcurrent type includes short-circuit overcurrent and impulse load overcurrent.

[0058] The source of a fault can be identified by the overcurrent type. Specifically, if the overcurrent type is a DC-side short-circuit overcurrent of the inverter module 20, the fault can be identified as a fault in the photovoltaic module and / or combiner box connected to the inverter module 20; if the overcurrent type is an AC-side overcurrent of the inverter module 20, the fault can be identified as at least one of the grid, load, or grid-connected relay. By identifying the overcurrent type, the fault point can be directly located, thereby significantly reducing the time for staff to troubleshoot and repair, and thus improving the operation and maintenance efficiency of the power station equipped with the fast transient overcurrent suppression circuit 10 of the photovoltaic inverter.

[0059] In one specific embodiment, the digital signal processing circuit 106 is further configured to generate a control signal to the drive circuit 108 according to the overcurrent type, so that the drive circuit 108 executes the fault handling strategy corresponding to the overcurrent type.

[0060] Fault handling strategies include attempting to reduce the output power of inverter module 20; automatically restarting multiple power switching devices after a preset delay; and, in the event of a severe fault, performing a permanent shutdown. Of course, after determining the fault handling strategy, the fault code can be reported to a remote terminal for staff to view.

[0061] Specifically, in the case of a conventional overcurrent, the digital signal processing circuit 106 can control the reduction of the output power of the inverter module 20 without requiring a shutdown.

[0062] In one embodiment, after handling the fault, the digital signal processing circuit 106 can also output a configuration signal to the logic operation circuit 104 to reconfigure the preset electrical signal threshold for the logic operation circuit 104. The digital signal processing circuit 106 can also output a fault flag clearing signal to the logic operation circuit 104 to clear the fault flag in the logic operation circuit 104, so that the fast transient overcurrent suppression circuit 10 of the photovoltaic inverter can return to normal operation or enter a safe state.

[0063] In one specific embodiment, after receiving the electrical signal to be tested and before outputting a blocking signal or a trigger signal, the logic operation circuit 104 is further configured to:

[0064] The electrical signal to be tested is preprocessed to obtain the preprocessed electrical signal to be tested.

[0065] The logic operation circuit 104 performs hardware preprocessing on the obtained electrical signal to be tested, eliminating the need for time-consuming computation processing by the digital signal processing circuit 106. This allows the preprocessing of the electrical signal to be tested to be completed with zero delay, achieving extremely fast response to overcurrent.

[0066] In one specific embodiment, preprocessing includes noise reduction.

[0067] The electrical signal to be tested obtained by the logic operation circuit 104 may include noise. Therefore, a digital filter can be built into the FPGA to remove high-frequency interference, thereby obtaining a clean electrical signal to be tested for numerical comparison. The digital filter can be a moving average filter or a median filter.

[0068] The preprocessing process is executed entirely in parallel by the FPGA hardware, without consuming software algorithm resources. The latency of hardware-parallel preprocessing can be as low as several clock cycles, resulting in a short delay.

[0069] In one specific embodiment, the sampling circuit 102 is used for:

[0070] The analog electrical signal on the AC side of the inverter module 20 is acquired.

[0071] The analog electrical signal is converted into a digital AC signal. The digital AC signal is adapted to the input requirements of the logic operation circuit 104.

[0072] The sampling circuit 102 includes a current sensor and a signal conditioning circuit interconnected. The current sensor collects analog electrical signals from the AC side of the inverter module 20 and transmits these signals to the signal conditioning circuit. The signal conditioning circuit receives the analog signals, converts them into digital AC signals, and transmits the digital AC signals to the logic operation circuit 104. For example, the current sensor may be a Hall effect sensor.

[0073] Therefore, in the aforementioned transient overcurrent suppression current, the logic operation circuit 104 is the core device for overcurrent detection, integrating a high-speed ADC (Analog-to-Digital) control interface, a preprocessing logic module, a real-time comparison operation logic module, a blocking logic module, and an interface with the digital signal processing circuit 106. The digital signal processing circuit 106 performs complex control operations when no overcurrent occurs. These complex control operations include maximum power point tracking, voltage and current dual closed-loop control, and PWM modulation signal calculation. The PWM modulation signal can be an SPWM (Sinusoidal Pulse Width Modulation) modulation signal.

[0074] In one embodiment, the drive circuit 108 is used to output a blocking signal or a modulated wave signal to multiple power switching devices after signal isolation and power amplification.

[0075] In one embodiment, after the fast transient overcurrent suppression circuit 10 of the photovoltaic inverter is powered on, the logic operation circuit 104 and the digital signal processing circuit 106 are initialized respectively. The digital signal processing circuit 106 is also used to set a preset electrical signal threshold for the logic operation circuit 104.

[0076] In a specific embodiment, such as Figure 2 As shown, a photovoltaic power generation system 1 is provided, including: an inverter module 20, a grid-connected relay 30, and a fast transient overcurrent suppression circuit 10 for the photovoltaic inverter as described above.

[0077] The DC side of inverter module 20 is used to connect to the output of the photovoltaic array.

[0078] The input terminal of the grid-connected relay 30 is connected to the AC side of the inverter module 20, and the output terminal of the grid-connected relay 30 is used to connect to the load.

[0079] The input terminal of the fast transient overcurrent suppression circuit 10 of the photovoltaic inverter is connected to the AC side of the inverter module 20, and the output terminal of the fast transient overcurrent suppression circuit 10 of the photovoltaic inverter is connected to the control terminal of multiple power switching devices in the inverter module 20.

[0080] Inverter module 20 converts the DC signal output from the photovoltaic array into an AC signal, which is then fed into the grid (public power grid) when grid-connected relay 30 is closed, for use by loads connected to the public power grid. The fast transient overcurrent suppression circuit 10 of the photovoltaic inverter detects and suppresses transient overcurrents while the circuit containing inverter module 20 and grid-connected relay 30 is operating normally, thereby ensuring the normal operation of the circuit and maintaining the stable and reliable operation of the power grid.

[0081] In a specific embodiment, such as Figure 2 As shown, the photovoltaic power generation system 1 also includes a filter circuit 40.

[0082] The input terminal of the filter circuit 40 is connected to the AC side of the inverter module 20, and the output terminal of the filter circuit 40 is connected to the input terminal of the grid-connected relay 30.

[0083] The electrical signal output by the inverter module 20 is fed into the public power grid after passing through the filter circuit 40. This process can suppress electromagnetic interference and improve the purity of the electrical signal fed into the public power grid, thereby ensuring that the electromagnetic compatibility of the photovoltaic power generation system 1 meets the standards and maintaining the operational stability of the photovoltaic power generation system 1.

[0084] In a specific embodiment, such as Figure 2 As shown, the photovoltaic power generation system 1 also includes a DC bus capacitor 50.

[0085] The DC bus capacitor 50 is connected in parallel between the positive and negative terminals of the DC bus of each inverter in the inverter module 20.

[0086] The DC bus capacitor 50 can filter out output fluctuations in electrical signals and high-frequency voltage ripples in the front-end circuit, and can also provide a clean and stable DC voltage for the downstream inverter module 20. The DC bus capacitor 50 can also absorb voltage spikes and surges generated by multiple power switching devices during the switching process, thereby preventing multiple power switching devices from being damaged due to overvoltage, and improving the electrical reliability of the photovoltaic power generation system 1.

[0087] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0088] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A fast transient overcurrent suppression circuit for a photovoltaic inverter, characterized in that, include: A sampling circuit, wherein the input terminal of the sampling circuit is used to connect to the AC side of the inverter module, and the sampling circuit is used to acquire the electrical signal to be measured output from the AC side of the inverter module; A logic operation circuit is provided, wherein the input terminal of the logic operation circuit is connected to the output terminal of the sampling circuit. The logic operation circuit is used to receive the electrical signal to be tested, and output a blocking signal when the electrical signal to be tested is greater than a preset electrical signal threshold, and output a trigger signal when the electrical signal to be tested is less than or equal to the preset electrical signal threshold; wherein, the logic operation circuit is an FPGA circuit. A digital signal processing circuit, wherein the input terminal of the digital signal processing circuit is connected to the first output terminal of the logic operation circuit; the digital signal processing circuit is used to receive and output a modulated wave signal based on the trigger signal; The driving circuit has a first input terminal connected to the second output terminal of the logic operation circuit, a second input terminal connected to the output terminal of the digital signal processing circuit, and an output terminal connected to the control terminal of multiple power switching devices in the inverter module. The driving circuit is used to turn off the multiple power switching devices when the blocking signal is received, and to turn on the multiple power switching devices when the modulation wave signal is received.

2. The fast transient overcurrent suppression circuit for a photovoltaic inverter according to claim 1, characterized in that, The logic operation circuit is also used for: Record and store multiple electrical signals to be tested, so as to obtain current waveform data based on the multiple electrical signals to be tested; When the electrical signal to be tested is greater than the preset electrical signal threshold, overcurrent data under overcurrent conditions is output; wherein, the overcurrent data includes the current waveform data.

3. The fast transient overcurrent suppression circuit for a photovoltaic inverter according to claim 2, characterized in that, The digital signal processing circuit is also used to receive and determine the overcurrent type based on the current waveform data.

4. The fast transient overcurrent suppression circuit for a photovoltaic inverter according to claim 3, characterized in that, The digital signal processing circuit is further configured to generate a control signal to the drive circuit according to the overcurrent type, so that the drive circuit executes the fault handling strategy corresponding to the overcurrent type.

5. The fast transient overcurrent suppression circuit for a photovoltaic inverter according to claim 1, characterized in that, After receiving the electrical signal to be tested, and before outputting the blocking signal or trigger signal, the logic operation circuit is further configured to: The electrical signal to be tested is preprocessed to obtain the preprocessed electrical signal to be tested.

6. The fast transient overcurrent suppression circuit for a photovoltaic inverter according to claim 5, characterized in that, The preprocessing includes noise reduction.

7. The fast transient overcurrent suppression circuit for a photovoltaic inverter according to claim 1, characterized in that, The sampling circuit is used for: The analog electrical signal on the AC side of the inverter module is acquired; The analog electrical signal is converted into a digital alternating current signal.

8. A photovoltaic power generation system, characterized in that, include: An inverter module, wherein the DC side of the inverter module is used to connect to the output terminal of the photovoltaic array; A grid-connected relay, the input terminal of which is connected to the AC side of the inverter module, and the output terminal of which is used to connect to the load; The fast transient overcurrent suppression circuit of the photovoltaic inverter as described in any one of claims 1-7, wherein the input terminal of the fast transient overcurrent suppression circuit of the photovoltaic inverter is connected to the AC side of the inverter module, and the output terminal of the fast transient overcurrent suppression circuit of the photovoltaic inverter is connected to the control terminal of a plurality of power switching devices in the inverter module.

9. The photovoltaic power generation system according to claim 8, characterized in that, Also includes: A filter circuit is provided, the input of which is connected to the AC side of the inverter module, and the output of which is connected to the input of the grid-connected relay.

10. The photovoltaic power generation system according to claim 8, characterized in that, Also includes: A DC bus capacitor is connected in parallel between the positive and negative terminals of the DC bus of each inverter in the inverter module.

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