A port low voltage ride through control system and method

Abstract

The application discloses a kind of port low voltage ride through control system and method.The application includes photovoltaic module carries out photoelectric conversion, is carried out three-phase interleaved boost by voltage conversion module, energy storage control module stores energy, by grid module detects grid fluctuation degree, when voltage fluctuation degree reaches first fluctuation threshold or when the time length reaching second fluctuation threshold exceeds timing time, energy storage control module discharges and by voltage conversion module carries out inverter frequency conversion, for the power supply of connected port load, according to the voltage size of the electric energy output by photovoltaic module and first voltage threshold, second voltage threshold and third voltage threshold, the electric energy superposition degree of control output conversion module.The application can carry out electric energy compensation processing to grid module, avoid voltage fluctuation of grid module, realize uninterrupted power supply, according to photoelectric state, carry out branch power supply, improve electric energy utilization.

Description

Technical Field

[0001] This invention relates to the field of port low voltage ride-through technology, specifically a port low voltage ride-through control system and method. Background Technology

[0002] Low voltage ride-through refers to the ability of a power generation system to operate uninterruptedly when a grid fault causes a voltage drop, thus navigating the low voltage period and providing necessary reactive power support to the grid. In existing technologies, ports typically use photovoltaic (PV) power systems for power generation. When a voltage drop is detected, the energy stored in the PV system's energy storage device powers port appliances and provides reactive power support to the grid. However, because the energy storage device provides backup power to both port appliances and the grid at this time, its power consumption rate is accelerated, reducing its endurance. Furthermore, during the discharge process of the energy storage device, the energy generated by the PV cannot be efficiently utilized, leading to a decrease in energy utilization efficiency. Therefore, improvements are needed. Summary of the Invention

[0003] This invention provides a port low voltage ride-through control method and system to solve the problems mentioned in the background art.

[0004] This invention provides a port low voltage ride-through control system, comprising:

[0005] A photovoltaic module is used for photoelectric conversion and outputting first electrical energy. It performs voltage sampling on the first electrical energy and outputs a first detection signal when the sampled signal is lower than a set first voltage threshold, a second detection signal when the sampled signal is lower than a second voltage threshold, and a fifth detection signal when the sampled signal is lower than a third voltage threshold.

[0006] The first type of electrical energy is the raw DC power generated by the photovoltaic module through photoelectric conversion;

[0007] The first voltage threshold is a relatively high threshold for the photovoltaic output voltage, used to determine whether to activate the single-phase boost mode. When the photovoltaic power generation is lower than the first voltage threshold, the voltage conversion module is controlled to perform single-phase boost operation. The first voltage threshold is the lowest input voltage when the voltage conversion module performs three-phase alternating transformation. The first voltage threshold is greater than the second voltage threshold, which is greater than the third voltage threshold.

[0008] The first detection signal indicates that the photovoltaic output voltage is lower than the first voltage threshold, triggering single-phase boost and dual-energy superposition;

[0009] The second voltage threshold is an intermediate threshold used to determine whether to activate the three-energy superposition mode;

[0010] The second detection signal indicates that the photovoltaic output voltage is lower than the second voltage threshold, triggering the superposition of three electrical energies;

[0011] The third voltage threshold is the minimum threshold used to determine whether to fully switch to energy storage power supply mode;

[0012] The fifth detection signal indicates that the photovoltaic output voltage is lower than the third voltage threshold, so photovoltaic power supply is stopped and switched to energy storage power supply.

[0013] The voltage conversion module is connected to the photovoltaic module and the energy storage control module. It is used to perform three-phase interleaved boost regulation on the first electrical energy and output the second electrical energy, perform single-phase boost regulation on the first electrical energy and output the third, fourth and fifth electrical energy respectively, and perform inverter and frequency conversion on the second electrical energy or the electrical energy released by the energy storage control module and output the eighth electrical energy.

[0014] The second electrical energy is the electrical energy formed after the first electrical energy output by the photovoltaic is regulated by the three-phase interleaved boost voltage regulation of the voltage conversion module;

[0015] The third, fourth, and fifth electrical energies are three types of electrical energies that are output from the first electrical energy output by the photovoltaic system after being regulated by the single-phase boost voltage of the voltage conversion module.

[0016] The eighth electrical energy is AC electrical energy output by the voltage conversion module after inverting and frequency converting the second electrical energy or the electrical energy released from the energy storage.

[0017] The output conversion module is connected to the voltage conversion module and the energy storage control module. It is used to superimpose the third, fourth and fifth electrical energy and output the sixth electrical energy, superimpose the third and fourth electrical energy and output the seventh electrical energy, transmit the fifth electrical energy to the energy storage control module and compensate for the electrical energy released by the energy storage control module.

[0018] The sixth electrical energy is obtained by superimposing the third, fourth, and fifth electrical energies.

[0019] The seventh electrical energy is obtained by superimposing the third and fourth electrical energies;

[0020] The power grid module, connected to the voltage conversion module, is used to receive AC power and perform voltage sampling, signal amplification, phase shifting, phase superposition, and absolute value processing on the AC power to output a voltage fluctuation signal. When the voltage fluctuation signal is greater than the set first fluctuation threshold, a third detection signal is output. When the duration of the voltage fluctuation signal being greater than the second fluctuation threshold reaches the timing time, a fourth detection signal is output, and the eighth power is received.

[0021] The first fluctuation threshold is the threshold for the power grid module to detect power grid voltage fluctuations. This first fluctuation threshold is greater than the second fluctuation threshold. The first fluctuation threshold is the maximum allowable level of power grid fluctuation. Once the higher fluctuation threshold is exceeded, a fast response is triggered, i.e., a third detection signal is output.

[0022] The third detection signal is a control signal output by the power grid detection unit based on the power grid voltage fluctuation.

[0023] The second fluctuation threshold is lower than the first fluctuation threshold. The second fluctuation threshold is the allowable level of power grid fluctuation. It is a lower fluctuation threshold, but if the duration of the power grid fluctuation reaching the second fluctuation threshold exceeds the "time period", a response will be triggered, that is, the fourth detection signal will be output.

[0024] The fourth detection signal represents a high voltage signal provided when the grid voltage fluctuation exceeds the second fluctuation threshold and the duration reaches a set value.

[0025] The energy storage control module is connected to the grid module to store secondary electrical energy, release the stored electrical energy and transmit the released electrical energy to the connected port load, and perform voltage reduction, rectification and stabilization of AC power to supply power to the port load.

[0026] The microcontroller module connects to the photovoltaic module, grid module, voltage conversion module, output conversion module, and energy storage control module. It controls the voltage conversion module to perform three-phase interleaved boost operation. Upon receiving the third or fourth detection signal, it controls the energy storage control module to stop power processing and controls the voltage conversion module to perform inverter / frequency conversion operation. If neither the first nor second detection signal is received, it controls the energy storage control module to supply power to the port load. Upon receiving the first detection signal, it controls the voltage conversion module to perform single-phase boost operation and performs voltage compensation processing for the energy storage control module. It also controls the output conversion module to perform dual-energy superposition operation and supply power to the port load. Upon receiving the second detection signal, it controls the output conversion module to perform three-energy superposition operation and supply power to the port load. Upon receiving the fifth detection signal, it stops the operation of the voltage conversion module and the output conversion module and controls the energy storage control module to supply power to the port load.

[0027] As a further embodiment of the present invention: the photovoltaic module includes a photovoltaic unit and a photovoltaic detection unit;

[0028] Preferably, the photovoltaic unit is used for photoelectric conversion and outputting the first electrical energy;

[0029] A photovoltaic detection unit, connected to a photovoltaic unit, is used to sample the voltage of the first electrical energy and output a first detection signal when the sampled signal is lower than a set first voltage threshold, a second detection signal when the sampled signal is lower than a second voltage threshold, and a fifth detection signal when the sampled signal is lower than a third voltage threshold.

[0030] As a further embodiment of the present invention: the power grid module includes a power grid unit and a power grid detection unit;

[0031] Preferably, the power grid unit is connected to the voltage conversion module for receiving AC power and receiving an eighth type of electrical energy;

[0032] The power grid detection unit, connected to the power grid unit, is used to perform voltage sampling, signal amplification, phase shifting, phase superposition, and absolute value processing on AC power and output voltage fluctuation signals. When the voltage fluctuation signal is greater than the set first fluctuation threshold, a third detection signal is output. When the duration of the voltage fluctuation signal being greater than the second fluctuation threshold reaches the timing time, a fourth detection signal is output.

[0033] As a further embodiment of the present invention: the photovoltaic unit includes a photovoltaic device, a first diode and a seventh capacitor; the voltage conversion module includes a first inductor, a second inductor, a third inductor, a first resistor, a second resistor, a third resistor, a first power transistor, a second power transistor, a third power transistor, a fifth thyristor, a sixth thyristor, a seventh thyristor and a third capacitor; the microcontroller module includes a first controller;

[0034] Preferably, the first end of the photovoltaic device is connected to the anode of the first diode. The cathode of the first diode is connected to one end of the first inductor, one end of the second inductor, and the first end of the third inductor, and is connected to the second end of the photovoltaic device, the emitter of the first power transistor, the emitter of the second power transistor, the emitter of the third power transistor, and one end of the third capacitor via a seventh capacitor. The other end of the first inductor is connected to the collector of the third power transistor and the anode of the fifth thyristor via a first resistor. The other end of the second inductor is connected to the anode of the sixth thyristor and the collector of the second power transistor via a second resistor. The other end of the third inductor is connected to the anode of the seventh thyristor and the collector of the first power transistor via a third resistor. The cathode of the fifth thyristor is connected to the cathodes of the sixth and seventh thyristors and the other end of the third capacitor. The gates of the first, second, and third power transistors, the control terminals of the fifth, sixth, and seventh thyristors are respectively connected to the IO1, IO2, IO3, IO12, IO13, and IO14 terminals of the first controller.

[0035] As a further embodiment of the present invention: the output conversion module includes a second diode, a first thyristor, a first capacitor, a third diode, a second thyristor, a second capacitor, a fourth diode, a third thyristor, and a fourth thyristor;

[0036] Preferably, the cathode of the second diode is connected to the control terminal of the third thyristor, the control terminal of the fourth thyristor, and the cathode of the fourth diode; the anode of the second diode is connected to the control terminal of the first thyristor and the IO4 terminal of the first controller; the anode of the fourth diode is connected to the control terminal of the second thyristor and the IO5 terminal of the first controller; the anodes of the first, third, and fourth thyristors are respectively connected to the anodes of the seventh, fifth, and sixth thyristors; the cathode of the first thyristor is connected to the anode of the third diode and connected to the anode of the second thyristor and the cathode of the third thyristor through a first capacitor; and the cathode of the third diode is connected to the cathode of the second thyristor and connected to the cathode of the fourth thyristor through a second capacitor.

[0037] As a further embodiment of the present invention: the output conversion module further includes an eighth diode, a fourth power transistor, and a first logic device; the energy storage control module includes an energy storage device, a fifth power transistor, a port load interface, and a voltage conversion device; the voltage conversion module further includes a first frequency converter; the power grid unit includes a power grid interface;

[0038] Preferably, the anode of the eighth diode is connected to the cathode of the third diode, the cathode of the eighth diode is connected to the collector of the fourth power transistor, the emitter of the fourth power transistor is connected to the emitter of the fifth power transistor and the first DC terminal of the port load interface, the collector of the fifth power transistor is connected to the first terminal of the energy storage device and the first input terminal of the first frequency converter, the second terminal of the energy storage device is connected to the second input terminal of the first frequency converter, the ground terminal of the port load interface, the second output terminal of the voltage conversion device and the second terminal of the photovoltaic device, the first output terminal of the first frequency converter is connected to the first terminal of the grid interface and the first input terminal of the voltage conversion device, the second output terminal of the first frequency converter is connected to the second terminal of the grid interface and the second input terminal of the voltage conversion device, the first output terminal of the voltage conversion device is connected to the second DC terminal of the port load interface, the gate of the fourth power transistor is connected to the Y terminal of the first logic device, the A terminal and B terminal of the first logic device are connected to the IO4 terminal and the IO5 terminal respectively, and the gate of the fifth power transistor is connected to the IO6 terminal of the first controller.

[0039] As a further embodiment of the present invention: the photovoltaic detection unit includes a fourth resistor, a fifth resistor, and a threshold comparison device;

[0040] Preferably, one end of the fourth resistor is connected to the first end of the photovoltaic device, and the other end of the fourth resistor is connected to the input end of the threshold comparison device and connected to the second end of the photovoltaic device through the fifth resistor. The first output end, the second output end, and the third output end of the threshold comparison device are respectively connected to the IO7 end, the IO8 end, and the IO11 end of the first controller.

[0041] As a further embodiment of the present invention: the power grid detection unit includes a first current transformer, an amplification and filtering device, a sixth resistor, a first operational amplifier, a fourth capacitor, a seventh resistor, an eighth resistor, a fifth capacitor, a ninth resistor, a tenth resistor, an eleventh resistor, and an absolute value device.

[0042] Preferably, the first and second terminals of the first current transformer are connected to the first and second terminals of the power grid interface, respectively. The third and fourth terminals of the first current transformer are connected to the first and second input terminals of the amplification and filtering device, respectively. The first output terminal of the amplification and filtering device is connected to one end of the seventh resistor and then connected to the inverting input of the first operational amplifier and one end of the eighth resistor in sequence through the sixth resistor and the fourth capacitor. The non-inverting input of the first operational amplifier is connected to one end of the ninth resistor and then connected to the output terminal of the first operational amplifier and one end of the eleventh resistor through the tenth resistor. The other end of the seventh resistor is connected to the other end of the eleventh resistor and the input terminal of the absolute value device. The other end of the eighth resistor is connected to the other end of the ninth resistor and the ground terminal through the fifth capacitor.

[0043] As a further embodiment of the present invention: the power grid detection unit further includes a first comparator, a second comparator, a twelfth resistor, a first reference power supply, a first regulated power supply, a thirteenth resistor, a fourteenth resistor, and a sixth capacitor;

[0044] Preferably, the non-inverting input of the first comparator is connected to the non-inverting input of the second comparator and the output of the absolute value device; the inverting input of the first comparator is connected to the first reference power supply and connected to the inverting input of the second comparator through the twelfth resistor; the output of the first comparator is connected to the IO10 terminal of the first controller; the output of the second comparator is connected to the base of the first switching transistor and one end of the sixth capacitor through the thirteenth resistor; the collector of the first switching transistor is connected to the first voltage regulator; and the emitter of the first switching transistor is connected to the IO9 terminal of the first controller and connected to the other end of the sixth capacitor and ground through the fourteenth resistor.

[0045] Furthermore, to achieve the above objectives, the present invention also proposes a port low-voltage ride-through control method, which is applied to the aforementioned port low-voltage ride-through control system. The steps of the control method include:

[0046] Preferably, the voltage fluctuation information detected by the power grid module and the photovoltaic power generation information of the photovoltaic module are obtained;

[0047] The voltage conversion module controls the three-phase interleaved boost operation, and the energy storage control module stores energy.

[0048] Based on voltage fluctuation information and photovoltaic power generation information, when the voltage fluctuation exceeds the set first fluctuation threshold or exceeds the second fluctuation threshold within a time period, the energy storage control module is controlled to stop power processing, and the voltage conversion module is controlled to perform inverter and frequency conversion work. When the photovoltaic power generation is not lower than the set first voltage threshold or second voltage threshold, the energy storage control module is controlled to supply power to the port load.

[0049] When the photovoltaic power generation is lower than the first voltage threshold, the control voltage conversion module performs single-phase boost operation and voltage compensation processing for the energy storage control module. The control output conversion module performs dual-energy superposition operation to supply power to the port load. When the photovoltaic power generation is lower than the second voltage threshold, the control output conversion module performs triple-energy superposition operation to supply power to the port load. When the photovoltaic power generation is lower than the third voltage threshold, the operation of the voltage conversion module and the output conversion module is stopped, and the control energy storage control module is controlled to supply power to the port load.

[0050] Compared with the prior art, the beneficial effects of the present invention are:

[0051] The port low-voltage ride-through control method and system of this invention can perform photoelectric conversion by a photovoltaic module, three-phase staggered boost by a voltage conversion module and stored by an energy storage control module, and the grid module detects the voltage fluctuation of the connected AC power. When the voltage fluctuation reaches a set first fluctuation threshold or the duration of reaching a second fluctuation threshold exceeds a set time, the microcontroller module controls the voltage conversion module to perform inverter and frequency conversion processing on the power released by the energy storage control module to supply power to the connected port load, so as to perform power compensation processing on the grid module, avoid voltage fluctuations in the grid module, and achieve uninterrupted power supply to the port load. At the same time, according to the voltage magnitude of the power output of the photovoltaic module and the first, second and third voltage thresholds, the superposition degree of the power output of the conversion module is controlled to complete the power supply control of the photovoltaic module and the energy storage control module, thereby improving the power utilization rate. Attached Figure Description

[0052] Figure 1 A schematic block diagram of a port low voltage ride-through control system provided in an embodiment of the present invention;

[0053] Figure 2 This is a schematic block diagram of the photovoltaic module provided in an embodiment of the present invention;

[0054] Figure 3 A schematic block diagram of the power grid module provided in an embodiment of the present invention;

[0055] Figure 4 A circuit diagram of a port low voltage ride-through control system provided in an embodiment of the present invention;

[0056] Figure 5 A circuit diagram of a photovoltaic detection unit provided in an embodiment of the present invention;

[0057] Figure 6 A circuit diagram of a power grid detection unit provided in an embodiment of the present invention;

[0058] Figure 7 This is a schematic flowchart of a port low-voltage ride-through control method provided in an embodiment of the present invention. Detailed Implementation

[0059] 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.

[0060] In one embodiment, see Figure 1 , Figure 2 and Figure 3 A port low voltage ride-through control system, comprising:

[0061] Photovoltaic module 1 is used for photoelectric conversion and outputting first electrical energy. It performs voltage sampling on the first electrical energy and outputs a first detection signal when the sampled signal is lower than a set first voltage threshold, a second detection signal when the sampled signal is lower than a second voltage threshold, and a fifth detection signal when the sampled signal is lower than a third voltage threshold.

[0062] The voltage conversion module 2 is connected to the photovoltaic module 1 and the energy storage control module 4. It is used to perform three-phase interleaved boost regulation on the first electrical energy and output the second electrical energy, perform single-phase boost regulation on the first electrical energy and output the third, fourth and fifth electrical energy respectively, and perform inverter frequency conversion on the second electrical energy or the electrical energy released by the energy storage control module 4 and output the eighth electrical energy.

[0063] Output conversion module 3 is connected to voltage conversion module 2 and energy storage control module 4. It is used to superimpose the third, fourth and fifth electrical energy and output the sixth electrical energy, superimpose the third and fourth electrical energy and output the seventh electrical energy, transmit the fifth electrical energy to energy storage control module 4 and compensate the electrical energy released by energy storage control module 4.

[0064] The power grid module 5 is connected to the voltage conversion module 2. It is used to receive AC power and perform voltage sampling, signal amplification, phase shifting, phase superposition and absolute value processing on the AC power and output voltage fluctuation signal. When the voltage fluctuation signal is greater than the set first fluctuation threshold, a third detection signal is output. When the duration of the voltage fluctuation signal being greater than the second fluctuation threshold reaches the timing time, a fourth detection signal is output and the eighth power is received.

[0065] The energy storage control module 4 is connected to the power grid module 5. It is used to store the second electrical energy, release the stored electrical energy and transmit the released electrical energy to the connected port load, perform voltage reduction, rectification and voltage stabilization of AC power and supply power to the port load.

[0066] The microcontroller module 6 is connected to the photovoltaic module 1, the grid module 5, the voltage conversion module 2, the output conversion module 3, and the energy storage control module 4. It controls the voltage conversion module 2 to perform three-phase interleaved boost operation. Upon receiving the third or fourth detection signal, it controls the energy storage control module 4 to stop power processing and controls the voltage conversion module 2 to perform inverter / frequency conversion operation. If neither the first nor the second detection signal is received, it controls the energy storage control module 4 to supply power to the port load. Upon receiving the first detection signal, it controls the voltage conversion module 2 to perform single-phase boost operation and performs voltage compensation processing on the energy storage control module 4. It also controls the output conversion module 3 to perform dual-energy superposition operation and supply power to the port load. Upon receiving the second detection signal, it controls the output conversion module 3 to perform three-energy superposition operation and supply power to the port load. Upon receiving the fifth detection signal, it stops the operation of the voltage conversion module 2 and the output conversion module 3 and controls the energy storage control module 4 to supply power to the port load.

[0067] Furthermore, the photovoltaic module 1 includes a photovoltaic unit 101 and a photovoltaic detection unit 102;

[0068] Specifically, the photovoltaic unit 101 is used for photoelectric conversion and outputting the first electrical energy;

[0069] The photovoltaic detection unit 102 is connected to the photovoltaic unit 101 and is used to sample the voltage of the first electrical energy. When the sampled signal is lower than the set first voltage threshold, it outputs a first detection signal, when the sampled signal is lower than the second voltage threshold, it outputs a second detection signal, and when the sampled signal is lower than the third voltage threshold, it outputs a fifth detection signal.

[0070] Furthermore, the power grid module 5 includes a power grid unit 501 and a power grid detection unit 502;

[0071] Specifically, the power grid unit 501 is connected to the voltage conversion module 2 and is used to access AC power and receive the eighth power.

[0072] The power grid detection unit 502 is connected to the power grid unit 501 and is used to perform voltage sampling, signal amplification, phase shifting, phase superposition and absolute value processing on AC power and output voltage fluctuation signals. When the voltage fluctuation signal is greater than the set first fluctuation threshold, a third detection signal is output. When the duration of the voltage fluctuation signal being greater than the second fluctuation threshold reaches the timing time, a fourth detection signal is output.

[0073] In a specific embodiment, the photovoltaic module 1 can be a photovoltaic circuit composed of a photovoltaic device, a resistor, a threshold comparison device, etc., to perform photoelectric conversion and voltage sampling, and compare the voltage with a set first voltage threshold, a second voltage threshold, and a third voltage threshold. The first voltage threshold is greater than the second voltage threshold and greater than the third voltage threshold. The first voltage threshold is the lowest input voltage when the voltage conversion module 2 performs three-phase alternating voltage transformation. The voltage conversion module 2 can be a voltage conversion circuit composed of an inductor, a resistor, a thyristor, an IGBT, etc., and can perform three-phase alternating voltage boost, single-phase voltage boost processing, and power transmission path control. The output conversion module 3 can be an output conversion circuit composed of a thyristor, a capacitor, a diode, an IGBT, etc., and can perform energy storage and power superposition processing, and change the degree of power superposition according to the change of power transmission path. The energy storage control module 4 can be an energy storage device, an IGBT, etc. The energy storage control circuit, composed of voltage conversion devices, etc., can store and discharge energy, control the transmission of electrical energy, supply power to the connected port load, and perform voltage reduction, rectification, and stabilization on the AC power connected to the power grid module 5. The aforementioned power grid module 5 can adopt a power grid circuit composed of a power grid interface, voltage transformer, amplification and filtering device, operational amplifier, comparator, etc., connected to the power grid and connected to AC power. It performs voltage sampling, signal amplification, phase shifting, phase superposition, and absolute value processing on the AC power, and compares the voltage with a set first fluctuation threshold and a second fluctuation threshold. The first fluctuation threshold is greater than the second fluctuation threshold, and the first fluctuation threshold is the allowable degree of power grid fluctuation. The aforementioned microcontroller module 6 can adopt a microcontroller circuit composed of a single-chip microcomputer, integrating many components such as an arithmetic unit, controller, memory, and input / output devices, to realize functions such as signal processing, data storage, module control, and timing control.

[0074] In this embodiment, please refer to Figure 4 , Figure 5 and Figure 6 The photovoltaic unit 101 includes a photovoltaic device, a first diode D1, and a seventh capacitor C7; the voltage conversion module 2 includes a first inductor L1, a second inductor L2, a third inductor L3, a first resistor R1, a second resistor R2, a third resistor R3, a first power transistor Q1, a second power transistor Q2, a third power transistor Q3, a fifth thyristor S5, a sixth thyristor S6, a seventh thyristor S7, and a third capacitor C3; the microcontroller module 6 includes a first controller U1;

[0075] Specifically, the first terminal of the photovoltaic device is connected to the anode of the first diode D1. The cathode of the first diode D1 is connected to one end of the first inductor L1, one end of the second inductor L2, and the first end of the third inductor L3, and is connected to the second terminal of the photovoltaic device, the emitter of the first power transistor Q1, the emitter of the second power transistor Q2, the emitter of the third power transistor Q3, and one end of the third capacitor C3 through the seventh capacitor C7. The other end of the first inductor L1 is connected to the collector of the third power transistor Q3 and the anode of the fifth thyristor S5 through the first resistor R1. The other end of the second inductor L2 is connected to the anode of the sixth thyristor S6 and the second power transistor S5 through the second resistor R2. The collector of power transistor Q2, the other end of the third inductor L3 is connected to the anode of the seventh thyristor S7 and the collector of the first power transistor Q1 through the third resistor R3. The cathode of the fifth thyristor S5 is connected to the cathode of the sixth thyristor S6, the cathode of the seventh thyristor S7 and the other end of the third capacitor C3. The gate of the first power transistor Q1, the gate of the second power transistor Q2, the gate of the third power transistor Q3, the control terminal of the fifth thyristor S5, the control terminal of the sixth thyristor S6 and the control terminal of the seventh thyristor S7 are respectively connected to the IO1, IO2, IO3, IO12, IO13 and IO14 terminals of the first controller U1.

[0076] In a specific embodiment, the photovoltaic device can be composed of multiple photovoltaic panels connected in series and parallel; the first controller U1 can be an STM32 microcontroller; the first power transistor Q1, the second power transistor Q2 and the third power transistor Q3 can all be IGBTs; the fifth thyristor S5, the sixth thyristor S6 and the seventh thyristor S7 can all be unidirectional thyristors.

[0077] Furthermore, the output conversion module 3 includes a second diode D2, a first thyristor S1, a first capacitor C1, a third diode D3, a second thyristor S2, a second capacitor C2, a fourth diode D4, a third thyristor S3, and a fourth thyristor S4.

[0078] Specifically, the cathode of the second diode D2 is connected to the control terminal of the third thyristor S3, the control terminal of the fourth thyristor S4, and the cathode of the fourth diode D4. The anode of the second diode D2 is connected to the control terminal of the first thyristor S1 and the IO4 terminal of the first controller U1. The anode of the fourth diode D4 is connected to the control terminal of the second thyristor S2 and the IO5 terminal of the first controller U1. The anodes of the first thyristor S1, the third thyristor S3, and the fourth thyristor S4 are respectively connected to the anodes of the seventh thyristor S7, the fifth thyristor S5, and the sixth thyristor S6. The cathode of the first thyristor S1 is connected to the anode of the third diode D3 and is connected to the anode of the second thyristor S2 and the cathode of the third thyristor S3 through the second capacitor C2. The cathode of the third diode D3 is connected to the cathode of the second thyristor S2 and is connected to the cathode of the fourth thyristor S4 through the second capacitor C2.

[0079] In a specific embodiment, the first thyristor S1, the second thyristor S2, the third thyristor S3, and the fourth thyristor S4 can all be unidirectional thyristors.

[0080] Furthermore, the output conversion module 3 also includes an eighth diode D8, a fourth power transistor Q4, and a first logic device J1; the energy storage control module 4 includes an energy storage device, a fifth power transistor Q5, a port load interface, and a voltage conversion device; the voltage conversion module 2 also includes a first frequency converter T1; and the grid unit 501 includes a grid interface.

[0081] Specifically, the anode of the eighth diode D8 is connected to the cathode of the third diode D3, the cathode of the eighth diode D8 is connected to the collector of the fourth power transistor Q4, the emitter of the fourth power transistor Q4 is connected to the emitter of the fifth power transistor Q5 and the first DC terminal of the port load interface, the collector of the fifth power transistor Q5 is connected to the first terminal of the energy storage device and the first input terminal of the first frequency converter T1, the second terminal of the energy storage device is connected to the second input terminal of the first frequency converter T1, the ground terminal of the port load interface, the second output terminal of the voltage conversion device and the second terminal of the photovoltaic device, the first output terminal of the first frequency converter T1 is connected to the first terminal of the grid interface and the first input terminal of the voltage conversion device, the second output terminal of the first frequency converter T1 is connected to the second terminal of the grid interface and the second input terminal of the voltage conversion device, the first output terminal of the voltage conversion device is connected to the second DC terminal of the port load interface, the gate of the fourth power transistor Q4 is connected to the Y terminal of the first logic device J1, the A terminal and the B terminal of the first logic device J1 are connected to the IO4 terminal and the IO5 terminal respectively, and the gate of the fifth power transistor Q5 is connected to the IO6 terminal of the first controller U1.

[0082] In a specific embodiment, the first logic device J1 can be an XOR gate; the energy storage device can be a battery; the fourth power transistor Q4 and the fifth power transistor Q5 can both be IGBTs; the first frequency converter T1 can be composed of four IGBTs; the voltage conversion device can be composed of a transformer, a rectifier and a boost circuit, and the boost device can be controlled by the first controller U1, which will not be elaborated further.

[0083] Furthermore, the photovoltaic detection unit 102 includes a fourth resistor R4, a fifth resistor R5, and a threshold comparison device;

[0084] Specifically, one end of the fourth resistor R4 is connected to the first end of the photovoltaic device, and the other end of the fourth resistor R4 is connected to the input end of the threshold comparator and connected to the second end of the photovoltaic device through the fifth resistor R5. The first output end, the second output end and the third output end of the threshold comparator are respectively connected to the IO7 end, the IO8 end and the IO11 end of the first controller U1.

[0085] In a specific embodiment, the threshold comparison device described above may consist of three sets of LM358 comparators and three sets of reference power supplies, and compare voltage magnitudes by setting a first voltage threshold, a second voltage threshold, and a third voltage threshold.

[0086] Furthermore, the power grid detection unit 502 includes a first current transformer PT1, an amplification and filtering device, a sixth resistor R6, a first operational amplifier OP1, a fourth capacitor C4, a seventh resistor R7, an eighth resistor R8, a fifth capacitor C5, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, and an absolute value device.

[0087] Specifically, the first and second terminals of the first current transformer PT1 are connected to the first and second terminals of the power grid interface, respectively. The third and fourth terminals of the first current transformer PT1 are connected to the first and second input terminals of the amplification and filtering device, respectively. The first output terminal of the amplification and filtering device is connected to one end of the seventh resistor R7 and then connected to the inverting terminal of the first operational amplifier OP1 and one end of the eighth resistor R8 in sequence through the sixth resistor R6 and the fourth capacitor C4. The non-inverting terminal of the first operational amplifier OP1 is connected to one end of the ninth resistor R9 and then connected to the output terminal of the first operational amplifier OP1 and one end of the eleventh resistor R11 through the tenth resistor R10. The other end of the seventh resistor R7 is connected to the other end of the eleventh resistor R11 and the input terminal of the absolute value device. The other end of the eighth resistor R8 is connected to the other end of the ninth resistor R9 and the ground terminal through the fifth capacitor C5.

[0088] In a specific embodiment, the first current transformer PT1 can be a voltage transformer; the amplification and filtering device can be composed of an operational amplifier, resistors and capacitors to amplify and filter signals; the first operational amplifier OP1 can be an OP07 operational amplifier; the absolute value device can be composed of an operational amplifier, resistors, capacitors and diodes to perform absolute value processing.

[0089] Furthermore, the power grid detection unit 502 also includes a first comparator A1, a second comparator A2, a twelfth resistor R12, a first reference power supply VF1, a first regulated power supply VCC1, a thirteenth resistor R13, a fourteenth resistor R14, and a sixth capacitor C6.

[0090] Specifically, the non-inverting input of the first comparator A1 is connected to the non-inverting input of the second comparator A2 and the output of the absolute value device. The inverting input of the first comparator A1 is connected to the first reference power supply VF1 and is connected to the inverting input of the second comparator A2 through the twelfth resistor R12. The output of the first comparator A1 is connected to the IO10 terminal of the first controller U1. The output of the second comparator A2 is connected to the base of the first switching transistor and one end of the sixth capacitor C6 through the thirteenth resistor R13. The collector of the first switching transistor is connected to the first regulated power supply VCC1. The emitter of the first switching transistor is connected to the IO9 terminal of the first controller U1 and is connected to the other end of the sixth capacitor C6 and the ground terminal through the fourteenth resistor R14.

[0091] In a specific embodiment, both the first comparator A1 and the second comparator A2 can be LM358 comparators; the first reference power supply VF1 provides a first fluctuation threshold, and after being stepped down by the twelfth resistor R12, it provides a second fluctuation threshold; the first switching transistor can be an NPN transistor, and the timing can be set by working with the thirteenth resistor R13 and the sixth capacitor C6.

[0092] In this embodiment, please refer to Figure 7 The present invention also proposes a port low-voltage ride-through control method, which is applied to the port low-voltage ride-through control system described above. The steps of the control method include:

[0093] S100: Obtain voltage fluctuation information detected by power grid module 5 and photovoltaic power generation information from photovoltaic module 1;

[0094] S200 controls the voltage conversion module 2 to perform three-phase interleaved boost operation and the energy storage control module 4 to perform energy storage.

[0095] S300. Based on voltage fluctuation information and photovoltaic power generation information, when the voltage fluctuation level is greater than the set first fluctuation threshold or greater than the second fluctuation threshold within a time period, control the energy storage control module 4 to stop power processing and control the voltage conversion module 2 to perform inverter and frequency conversion work. When the photovoltaic power generation is not lower than the set first voltage threshold or second voltage threshold, control the energy storage control module 4 to supply power to the port load.

[0096] S400: When the photovoltaic power generation is lower than the first voltage threshold, control the voltage conversion module 2 to perform single-phase boost operation and control the voltage conversion module 2 to perform voltage compensation processing on the energy storage control module 4. Control the output conversion module 3 to perform dual energy superposition operation and supply power to the port load. When the photovoltaic power generation is lower than the second voltage threshold, control the output conversion module 3 to perform triple energy superposition operation and supply power to the port load. When the photovoltaic power generation is lower than the third voltage threshold, stop the operation of the voltage conversion module 2 and the output conversion module 3 and control the energy storage control module 4 to supply power to the port load.

[0097] In this embodiment of a port low-voltage ride-through control system, a photovoltaic device performs photoelectric conversion. After rectification and filtering by the first diode D1 and the seventh capacitor C7, the first electrical energy is output. The first controller U1 controls the working states of the first power transistor Q1, the second power transistor Q2, and the third power transistor Q3, and controls the conduction of the fifth thyristor S5, the sixth thyristor S6, and the seventh thyristor S7. This, in conjunction with the first inductor L1, the second inductor L2, the third inductor L3, the first resistor R1, the second resistor R2, and the third resistor R3, performs three-phase alternating voltage boosting, which is then stored in an energy storage device. AC power is connected to the grid interface, processed by a voltage conversion device, and transmitted to the port load connected to the port load interface. The first current transformer PT1 and an amplification and filtering device then perform electrical... The signal undergoes sampling, amplification, and filtering. The processed signal is then phase-shifted 180 degrees by the first operational amplifier OP1, the sixth resistor R6, the fourth capacitor C4, the eighth resistor R8, the fifth capacitor C5, the ninth resistor R9, the tenth resistor R10, and the eleventh resistor R11. This phase-shifted signal is superimposed on the signal transmitted by the seventh resistor R7. If the superimposed voltage is not zero, it indicates a voltage fluctuation. After processing by an absolute value device, the signal undergoes first voltage fluctuation detection via the first comparator A1 and the first reference power supply VF1. Second voltage fluctuation detection is performed via the second comparator A2, the twelfth resistor R12, and the first reference power supply VF1. When the voltage fluctuation exceeds the first threshold, the first comparator A1 outputs a high level, indicating the third detection. When the signal exceeds the second voltage fluctuation threshold, the second comparator A2 outputs a high level, the sixth capacitor C6 stores energy, and when the duration exceeds the timing period, the first switch transistor turns on. The first controller U1 receives the fourth detection signal. Upon receiving either the third or fourth detection signal, the first controller U1 controls the first inverter T1 to perform inverter / frequency conversion processing on the energy released by the energy storage device. If the signal sampled by the fourth resistor R4 and the fifth resistor R5 is not less than the first voltage threshold, the first controller U1 controls the fifth power transistor Q5 to turn on, so that the energy storage device also supplies power to the port load. If the sampled signal is less than the first voltage threshold, the control of the fifth power transistor Q5 will stop, and the first controller U1 will stop controlling the fifth thyristor S5 and the sixth thyristor S6. When S6 is turned on, voltage conversion module 2 performs single-phase boost control. Resistors R1, R2, and R3 output the third, fourth, and fifth electrical energies respectively. Controller U1 controls S2 and S4 to turn on, allowing the third and fourth electrical energies to be superimposed through capacitor C2. Logic unit J1 controls power transistor Q4 to turn on, directly transmitting the superimposed energy to the port load interface. The energy storage device supplies power to the grid through inverter T1. The fifth electrical energy transmitted by S7 compensates for the energy released by the energy storage device. When the sampled signal is less than the second voltage threshold, control of S5, S6, and S7 will cease.The system controls the conduction of the first thyristor S1, the third thyristor S3, and the fourth thyristor S4, enabling the third, fourth, and fifth electrical energies to be superimposed through the first capacitor C1 and the second capacitor C2, and then transmitted to the port load through the eighth diode D8 and the fourth power transistor Q4. When the sampled signal is less than the third voltage threshold, the operation of the voltage conversion module 2 is stopped, and power supply to the port load is restored by the energy storage device through the fifth power transistor Q5.

[0098] 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.

[0099] 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 port low-voltage ride-through control system, characterized in that, The system includes: A photovoltaic module is used for photoelectric conversion and outputting first electrical energy. It performs voltage sampling on the first electrical energy and outputs a first detection signal when the sampled signal is lower than a set first voltage threshold, a second detection signal when the sampled signal is lower than a second voltage threshold, and a fifth detection signal when the sampled signal is lower than a third voltage threshold. The voltage conversion module is connected to the photovoltaic module and the energy storage control module. It is used to perform three-phase interleaved boost regulation on the first electrical energy and output the second electrical energy, perform single-phase boost regulation on the first electrical energy and output the third, fourth and fifth electrical energy respectively, and perform inverter and frequency conversion on the second electrical energy or the electrical energy released by the energy storage control module and output the eighth electrical energy. The output conversion module is connected to the voltage conversion module and the energy storage control module. It is used to superimpose the third, fourth and fifth electrical energy and output the sixth electrical energy, superimpose the third and fourth electrical energy and output the seventh electrical energy, transmit the fifth electrical energy to the energy storage control module and compensate for the electrical energy released by the energy storage control module. The power grid module, connected to the voltage conversion module, is used to receive AC power and perform voltage sampling, signal amplification, phase shifting, phase superposition, and absolute value processing on the AC power to output a voltage fluctuation signal. When the voltage fluctuation signal is greater than the set first fluctuation threshold, a third detection signal is output. When the duration of the voltage fluctuation signal being greater than the second fluctuation threshold reaches the timing time, a fourth detection signal is output, and the eighth power is received. The energy storage control module is connected to the grid module to store secondary electrical energy, release the stored electrical energy and transmit the released electrical energy to the connected port load, and perform voltage reduction, rectification and stabilization of AC power to supply power to the port load. The microcontroller module is connected to the photovoltaic module, grid module, voltage conversion module, output conversion module, and energy storage control module, respectively. It is used to control the voltage conversion module to perform three-phase interleaved boost operation. When the third or fourth detection signal is received, it controls the energy storage control module to stop power processing and controls the voltage conversion module to perform inverter and frequency conversion operation. When the first or second detection signal is not received, it controls the energy storage control module to supply power to the port load. When the first detection signal is received, it controls the voltage conversion module to perform single-phase boost operation and controls the voltage conversion module to perform voltage compensation processing for the energy storage control module. It controls the output conversion module to perform dual power superposition operation and supply power to the port load. When the second detection signal is received, it controls the output conversion module to perform three power superposition operation and supply power to the port load. When the fifth detection signal is received, it stops the operation of the voltage conversion module and the output conversion module and controls the energy storage control module to supply power to the port load. The photovoltaic module includes a photovoltaic unit and a photovoltaic detection unit; The power grid module includes a power grid unit and a power grid detection unit; The photovoltaic unit includes a photovoltaic device, a first diode, and a seventh capacitor; the voltage conversion module includes a first inductor, a second inductor, a third inductor, a first resistor, a second resistor, a third resistor, a first power transistor, a second power transistor, a third power transistor, a fifth thyristor, a sixth thyristor, a seventh thyristor, and a third capacitor; the microcontroller module includes a first controller; The first end of the photovoltaic device is connected to the anode of the first diode. The cathode of the first diode is connected to one end of the first inductor, one end of the second inductor, and the first end of the third inductor, and is connected to the second end of the photovoltaic device, the emitter of the first power transistor, the emitter of the second power transistor, the emitter of the third power transistor, and one end of the third capacitor through the seventh capacitor. The other end of the first inductor is connected to the collector of the third power transistor and the anode of the fifth thyristor through the first resistor. The other end of the second inductor is connected to the anode of the sixth thyristor and the collector of the second power transistor through the second resistor. The other end of the third inductor is connected to the anode of the seventh thyristor and the collector of the first power transistor through the third resistor. The cathode of the fifth thyristor is connected to the cathodes of the sixth and seventh thyristors and the other end of the third capacitor. The gates of the first power transistor, the second power transistor, the third power transistor, the control terminals of the fifth, sixth, and seventh thyristors are respectively connected to the IO1, IO2, IO3, IO12, IO13, and IO14 terminals of the first controller. The output conversion module includes a second diode, a first thyristor, a first capacitor, a third diode, a second thyristor, a second capacitor, a fourth diode, a third thyristor, and a fourth thyristor. The cathode of the second diode is connected to the control terminal of the third thyristor, the control terminal of the fourth thyristor, and the cathode of the fourth diode. The anode of the second diode is connected to the control terminal of the first thyristor and the IO4 terminal of the first controller. The anode of the fourth diode is connected to the control terminal of the second thyristor and the IO5 terminal of the first controller. The anodes of the first, third, and fourth thyristors are respectively connected to the anodes of the seventh, fifth, and sixth thyristors. The cathode of the first thyristor is connected to the anode of the third diode and is connected to the anode of the second thyristor and the cathode of the third thyristor through the first capacitor. The cathode of the third diode is connected to the cathode of the second thyristor and is connected to the cathode of the fourth thyristor through the second capacitor. The output conversion module further includes an eighth diode, a fourth power transistor, and a first logic unit; the energy storage control module includes an energy storage device, a fifth power transistor, a port load interface, and a voltage conversion device; the voltage conversion module further includes a first frequency converter; the power grid unit includes a power grid interface; The anode of the eighth diode is connected to the cathode of the third diode, the cathode of the eighth diode is connected to the collector of the fourth power transistor, the emitter of the fourth power transistor is connected to the emitter of the fifth power transistor and the first DC terminal of the port load interface, the collector of the fifth power transistor is connected to the first terminal of the energy storage device and the first input terminal of the first frequency converter, the second terminal of the energy storage device is connected to the second input terminal of the first frequency converter, the ground terminal of the port load interface, the second output terminal of the voltage conversion device and the second terminal of the photovoltaic device, the first output terminal of the first frequency converter is connected to the first terminal of the grid interface and the first input terminal of the voltage conversion device, the second output terminal of the first frequency converter is connected to the second terminal of the grid interface and the second input terminal of the voltage conversion device, the first output terminal of the voltage conversion device is connected to the second DC terminal of the port load interface, the gate of the fourth power transistor is connected to the Y terminal of the first logic device, the A terminal and B terminal of the first logic device are connected to the IO4 terminal and the IO5 terminal respectively, and the gate of the fifth power transistor is connected to the IO6 terminal of the first controller. The power grid detection unit includes a first current transformer, an amplification and filtering device, a sixth resistor, a first operational amplifier, a fourth capacitor, a seventh resistor, an eighth resistor, a fifth capacitor, a ninth resistor, a tenth resistor, an eleventh resistor, and an absolute value device. The first and second ends of the first current transformer are respectively connected to the first and second ends of the power grid interface. The third and fourth ends of the first current transformer are respectively connected to the first and second input ends of the amplification and filtering device. The first output end of the amplification and filtering device is connected to one end of the seventh resistor and then connected to the inverting input of the first operational amplifier and one end of the eighth resistor in sequence through the sixth resistor and the fourth capacitor. The non-inverting input of the first operational amplifier is connected to one end of the ninth resistor and then connected to the output end of the first operational amplifier and one end of the eleventh resistor through the tenth resistor. The other end of the seventh resistor is connected to the other end of the eleventh resistor and the input end of the absolute value device. The other end of the eighth resistor is connected to the other end of the ninth resistor and the ground terminal through the fifth capacitor. The power grid detection unit also includes a first comparator, a second comparator, a twelfth resistor, a first reference power supply, a first voltage regulator, a thirteenth resistor, a fourteenth resistor, a first switching transistor, and a sixth capacitor; The non-inverting input of the first comparator is connected to the non-inverting input of the second comparator and the output of the absolute value device. The inverting input of the first comparator is connected to the first reference power supply and is connected to the inverting input of the second comparator through the twelfth resistor. The output of the first comparator is connected to the IO10 terminal of the first controller. The output of the second comparator is connected to the base of the first switching transistor and one end of the sixth capacitor through the thirteenth resistor. The collector of the first switching transistor is connected to the first voltage regulator. The emitter of the first switching transistor is connected to the IO9 terminal of the first controller and is connected to the other end of the sixth capacitor and ground through the fourteenth resistor.

2. The port low voltage ride-through control system according to claim 1, characterized in that, The photovoltaic unit is used for photoelectric conversion and outputting first electrical energy; the photovoltaic detection unit is connected to the photovoltaic unit and is used for voltage sampling of the first electrical energy and outputting a first detection signal when the sampled signal is lower than a set first voltage threshold, outputting a second detection signal when the sampled signal is lower than a second voltage threshold, and outputting a fifth detection signal when the sampled signal is lower than a third voltage threshold.

3. A port low-voltage ride-through control system according to claim 1, characterized in that, The power grid unit is connected to the voltage conversion module for receiving AC power and receiving eighth type of power. The power grid detection unit, connected to the power grid unit, is used to perform voltage sampling, signal amplification, phase shifting, phase superposition, and absolute value processing on AC power and output voltage fluctuation signals. When the voltage fluctuation signal is greater than the set first fluctuation threshold, a third detection signal is output. When the duration of the voltage fluctuation signal being greater than the second fluctuation threshold reaches the timing time, a fourth detection signal is output.

4. A port low-voltage ride-through control system according to claim 1, characterized in that, The photovoltaic detection unit includes a fourth resistor, a fifth resistor, and a threshold comparison device; One end of the fourth resistor is connected to the first end of the photovoltaic device, and the other end of the fourth resistor is connected to the input end of the threshold comparison device and connected to the second end of the photovoltaic device through the fifth resistor. The first output end, the second output end, and the third output end of the threshold comparison device are respectively connected to the IO7 end, the IO8 end, and the IO11 end of the first controller.

5. A port low-voltage ride-through control method, characterized in that, The control method, applied to the port low-voltage ride-through control system according to claim 1, 2, 3, or 4, includes the following steps: First: Obtain voltage fluctuation information detected by the power grid module and photovoltaic power generation information from the photovoltaic module; Secondly: control the voltage conversion module to perform three-phase interleaved boost operation and the energy storage control module to perform energy storage; Then: based on voltage fluctuation information and photovoltaic power generation information, when the voltage fluctuation level is greater than the set first fluctuation threshold or when the duration of the voltage fluctuation level being greater than the second fluctuation threshold reaches the set time, the energy storage control module is controlled to stop power processing, and the voltage conversion module is controlled to perform inverter and frequency conversion work. When the photovoltaic power generation is not lower than the set first voltage threshold or second voltage threshold, the energy storage control module is controlled to supply power to the port load. Finally: When the photovoltaic power generation is lower than the first voltage threshold, the voltage conversion module is controlled to perform single-phase boost operation and voltage compensation processing for the energy storage control module. The output conversion module is controlled to perform dual-energy superposition operation and supply power to the port load. When the photovoltaic power generation is lower than the second voltage threshold, the output conversion module is controlled to perform triple-energy superposition operation and supply power to the port load. When the photovoltaic power generation is lower than the third voltage threshold, the voltage conversion module and the output conversion module are stopped, and the energy storage control module is controlled to supply power to the port load.

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