Soft start protection circuit, control method thereof and storage medium

Abstract

The application discloses a soft-start protection circuit and a control method and a storage medium thereof, and is applied to a grid-connected energy storage inverter, wherein the circuit comprises: a rectifying module, an input end of the rectifying module being connected with an alternating current grid; a switching module, one end of the switching module being connected with an output end of the rectifying module; a power capacitor charging branch, one end of the power capacitor charging branch being connected with the other end of the switching module, and the other end of the power capacitor charging branch being connected with the grid-connected energy storage inverter; an auxiliary power supply charging branch, one end of the auxiliary power supply charging branch being connected with the other end of the switching module, and the other end of the auxiliary power supply charging branch being connected with an auxiliary power supply; and a decoupling branch, the decoupling branch being connected between the other end of the power capacitor charging branch and the other end of the auxiliary power supply charging branch, and being used for decoupling the auxiliary power supply charging branch from the power capacitor charging branch when the power capacitor charging branch is short-circuited. The controller can be ensured not to be powered off, and fault self-locking and fault information reporting can be realized.

Description

Technical Field

[0001] This invention relates to the field of energy storage inverter technology, and in particular to a soft-start protection circuit and its control method, as well as a storage medium. Background Technology

[0002] The grid-side soft-start circuit of a grid-connected energy storage inverter is mainly used to limit the charging current of the bus capacitor (BUS capacitor) during system startup, preventing excessive inrush current from damaging upstream components. Related technologies typically employ a relay combined with a current-limiting resistor; that is, after grid rectification, the BUS capacitor is charged with current-limited power through a relay and current-limiting resistor connected in series. Some solutions, to further improve protection reliability, incorporate a thermistor in series in the circuit, utilizing its characteristic of a sharp increase in resistance during overcurrent to achieve current-limiting protection. However, the above-mentioned solutions have the following drawbacks: when the entire unit fails, such as a fault in the inverter circuit or DC-DC circuit, the BUS capacitor will typically short-circuit. This fault will cause the input power of the downstream auxiliary power supply to drop, resulting in a power-down of the entire unit, making fault diagnosis, fault saving, and fault reporting impossible. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to propose a soft-start protection circuit that, when a short-circuit fault occurs in the power capacitor charging branch, isolates the auxiliary power charging branch from the fault point through a decoupling branch, maintaining continuous power supply to the auxiliary power supply, ensuring the controller does not lose power, achieving fault self-locking and fault information reporting, preventing system loss of control, and simultaneously preventing component overheating and damage caused by fault propagation, thus improving the reliability and safety of the circuit.

[0004] The second objective of this invention is to provide a control method for a soft-start protection circuit.

[0005] A third objective of this invention is to provide a computer-readable storage medium.

[0006] To achieve the above objectives, a first aspect of the present invention provides a soft-start protection circuit applied to a grid-connected energy storage inverter, comprising: a rectifier module, the input terminal of which is connected to the AC grid; a switching module, one end of which is connected to the output terminal of the rectifier module; a power capacitor charging branch, one end of which is connected to the other end of the switching module and the other end of which is connected to the grid-connected energy storage inverter; an auxiliary power supply charging branch, one end of which is connected to the other end of the switching module and the other end of which is connected to an auxiliary power supply; and a decoupling branch, connected between the other end of the power capacitor charging branch and the other end of the auxiliary power supply charging branch, for decoupling the auxiliary power supply charging branch from the power capacitor charging branch when the power capacitor charging branch is short-circuited.

[0007] According to the soft-start protection circuit of the present invention, when a short circuit fault occurs in the power capacitor charging branch, the auxiliary power charging branch can be isolated from the fault point through the decoupling branch, maintaining the continuous power supply of the auxiliary power supply, ensuring that the controller does not lose power, realizing fault self-locking and fault information reporting, avoiding system loss of control, and preventing the components from overheating and being damaged due to the spread of the fault, thereby improving the reliability and safety of the circuit.

[0008] In addition, the soft-start protection circuit according to the above embodiments of the present invention may further include the following additional technical features: According to one embodiment of the present invention, the output terminal of the rectifier module is connected to the positive DC bus and the negative DC bus respectively, and the switching module includes at least one relay, which is connected to the positive DC bus or the negative DC bus and is used to control the on / off state of the DC bus.

[0009] According to one embodiment of the present invention, the power capacitor charging branch includes a first thermistor, a first resistor, and a second resistor. One end of the first thermistor is connected to the first output terminal of the switching module, and the other end of the first thermistor is connected to one end of the first resistor. The other end of the first resistor is connected to the first input terminal of the grid-connected energy storage inverter. One end of the second resistor is connected to the first output terminal of the switching module, and the other end of the second resistor is connected to the second input terminal of the grid-connected energy storage inverter.

[0010] According to one embodiment of the present invention, the power capacitor charging branch further includes a first capacitor, one end of which is connected to a first input terminal of the grid-connected energy storage inverter, and the other end of which is connected to a second input terminal of the grid-connected energy storage inverter.

[0011] According to one embodiment of the present invention, the auxiliary power charging branch includes a second thermistor, a first diode, and a second diode. The anode of the first diode is connected to the first output terminal of the switching module, the cathode of the first diode is connected to one end of the second thermistor, the other end of the second thermistor is connected to the positive terminal of the auxiliary power supply, the cathode of the second diode is connected to the second output terminal of the switching module, and the anode of the second diode is connected to the negative terminal of the auxiliary power supply.

[0012] According to one embodiment of the present invention, the auxiliary power charging branch further includes a second capacitor, one end of which is connected to the positive terminal of the auxiliary power supply, and the other end of which is connected to the negative terminal of the auxiliary power supply.

[0013] According to one embodiment of the present invention, the decoupling branch includes a third diode and a fourth diode. The cathode of the third diode is connected to the positive terminal of the auxiliary power supply, the anode of the third diode is connected to the first input terminal of the grid-connected energy storage inverter, the anode of the fourth diode is connected to the negative terminal of the auxiliary power supply, and the cathode of the fourth diode is connected to the second input terminal of the grid-connected energy storage inverter.

[0014] To achieve the above objectives, a second aspect of the present invention provides a control method for the soft-start protection circuit described in the above embodiments of the present invention, wherein the grid-connected energy storage inverter is also connected to an energy storage device. The method includes: acquiring the input voltage of the grid-connected energy storage inverter, the energy storage voltage of the energy storage device, the access information of the AC grid, and the fault information of the soft-start protection circuit; and controlling the switching module according to multiple of the input voltage, the energy storage voltage, the access information, and the fault information.

[0015] The control method of the soft-start protection circuit according to the present invention can isolate the auxiliary power supply charging branch from the fault point through the decoupling branch when a short circuit fault occurs in the power capacitor charging branch, maintain the continuous power supply of the auxiliary power supply, ensure that the controller does not lose power, realize fault self-locking and fault information reporting, avoid system loss of control, and prevent the components from overheating and being damaged due to fault propagation, thereby improving the reliability and safety of the circuit.

[0016] In addition, the control method for the soft-start protection circuit according to the above embodiments of the present invention may further include the following additional technical features: According to one embodiment of the present invention, controlling the switching module based on multiple factors including the input voltage, the energy storage voltage, the access information, and the fault information includes: controlling the switching module to close when the input voltage is less than or equal to a first preset voltage and the AC grid is determined to be connected according to the access information; controlling the switching module to open when the input voltage is less than or equal to the first preset voltage and the AC grid is determined to be disconnected according to the access information; controlling the switching module to open when the input voltage is greater than the first preset voltage and the energy storage voltage is greater than or equal to a second preset voltage; and controlling the switching module to open when the input voltage is greater than the first preset voltage and the energy storage voltage is greater than or equal to a second preset voltage. When the energy storage voltage is less than the second preset voltage and the AC grid is not connected according to the access information, the switch module is controlled to open; when the input voltage is greater than the first preset voltage, the energy storage voltage is less than the second preset voltage, the AC grid is connected according to the access information, and the soft-start protection circuit is in normal mode according to the fault information, the switch module is controlled to close; when the input voltage is greater than the first preset voltage, the energy storage voltage is less than the second preset voltage, the AC grid is connected according to the access information, and the soft-start protection circuit is in fault mode according to the fault information, the switch module is controlled to open.

[0017] To achieve the above objectives, a third aspect of the present invention provides a computer-readable storage medium storing a control program for a soft-start protection circuit, wherein the control program for the soft-start protection circuit, when executed by a processor, implements the control method for the soft-start protection circuit described in the aforementioned embodiments of the present invention.

[0018] According to the computer-readable storage medium of the present invention, when a short circuit fault occurs in the power capacitor charging branch, the auxiliary power charging branch is isolated from the fault point by the decoupling branch, the auxiliary power supply is continuously supplied, the controller is not powered down, fault self-locking and fault information reporting are realized, the system is prevented from going out of control, and the overheating and damage of components caused by the fault propagation are prevented, thereby improving the reliability and safety of the circuit.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] Figure 1 This is a block diagram of a soft-start protection circuit according to an embodiment of the present invention; Figure 2 This is a circuit diagram of the soft-start protection circuit according to an embodiment of the present invention; Figure 3This is a flowchart illustrating the control method of the soft-start protection circuit according to an embodiment of the present invention.

[0021] Figure label: The circuit includes a soft-start protection circuit 100, a rectifier module 10, a switch module 20, a power capacitor charging branch 30, an auxiliary power supply charging branch 40, a decoupling branch 50, an AC grid 60, a grid-connected energy storage inverter 70, an auxiliary power supply 80, a first thermistor PTC1, a first resistor R1, a second resistor R2, a first capacitor C1, a second thermistor PTC2, a first diode D1, a second diode D2, a second capacitor C2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8, a first relay PLY1, and a second relay PLY2. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] The soft-start protection circuit and its control method according to embodiments of the present invention are described below with reference to the accompanying drawings.

[0024] Figure 1 This is a block diagram of a soft-start protection circuit according to an embodiment of the present invention.

[0025] Specifically, in some embodiments of the present invention, such as Figure 1 As shown, a soft-start protection circuit is applied to a grid-connected energy storage inverter. The soft-start protection circuit 100 includes a rectifier module 10, a switch module 20, a power capacitor charging branch 30, an auxiliary power supply charging branch 40, and a decoupling branch 50.

[0026] The rectifier module 10 has its input terminal connected to the AC power grid 60; one end of the switch module 20 is connected to the output terminal of the rectifier module 10; one end of the power capacitor charging branch 30 is connected to the other end of the switch module 20, and the other end of the power capacitor charging branch 30 is connected to the grid-connected energy storage inverter 70; one end of the auxiliary power charging branch 40 is connected to the other end of the switch module 20, and the other end of the auxiliary power charging branch 40 is connected to the auxiliary power supply 80; and the decoupling branch 50 is connected between the other end of the power capacitor charging branch 30 and the other end of the auxiliary power charging branch 40, and is used to decouple the auxiliary power charging branch 40 from the power capacitor charging branch 30 when the power capacitor charging branch 30 is short-circuited.

[0027] Specifically, in this embodiment, the rectifier module 10 is used to rectify AC power into DC power, such as... Figure 2 As shown, the rectifier module 10 can employ a bridge rectifier circuit composed of four diodes, with its output terminals connected to the positive DC bus (+BUS) and the negative DC bus (-BUS) respectively. The switching module 20 includes at least one relay, which is connected to either the positive or negative DC bus and used to control the on / off state of the DC bus. Preferably, the relay is a normally closed relay to ensure that the switching module 20 is in the conducting state when the system is not powered on, facilitating power supply to the system after grid connection.

[0028] It should be noted that, in a specific embodiment of the present invention, the rectifier module 10 includes a fifth diode D5, a sixth diode D6, a seventh diode D7, and an eighth diode D8. The anode of the fifth diode D5 and the cathode of the sixth diode D6 are connected to the first terminal of the AC power grid 60, and the anode of the seventh diode D7 and the cathode of the eighth diode D8 are connected to the second terminal of the AC power grid 60. The cathodes of the fifth diode D5 and the seventh diode D7 are connected to the positive DC bus (+BUS), and the anodes of the sixth diode D6 and the eighth diode D8 are connected to the negative DC bus (-BUS). The relays may include a first relay PLY1 and a second relay PLY2, which are connected in series on the bus. When the controller outputs a control signal, it can control the first and second relays to open or close simultaneously.

[0029] Furthermore, in some embodiments of the present invention, such as Figure 2 As shown in the circuit diagram, the power capacitor charging branch 30 includes a first thermistor PTC1, a first resistor R1, and a second resistor R2. One end of the first thermistor PTC1 is connected to the first output terminal of the switching module 20, and the other end of the first thermistor PTC1 is connected to one end of the first resistor R1. The other end of the first resistor R1 is connected to the first input terminal of the grid-connected energy storage inverter 70. One end of the second resistor R2 is connected to the first output terminal of the switching module 20, and the other end of the second resistor R2 is connected to the second input terminal of the grid-connected energy storage inverter 70.

[0030] Specifically, in this embodiment, the first thermistor PTC1 and the first resistor R1 are connected in series between the positive DC bus and the positive terminal of the first capacitor C1, and the second resistor R2 is directly connected between the positive DC bus and the negative terminal of the first capacitor C1. When the system starts up, the first thermistor PTC1, the first resistor R1, and the second resistor R2 together limit the charging current of the first capacitor C1 to prevent excessive inrush current from damaging the upstream components. When a prolonged overcurrent occurs in the power capacitor charging branch 30, the resistance of the first thermistor PTC1 increases sharply due to heat, further limiting the fault current and protecting the first resistor R1 and the second resistor R2 from overheating and damage.

[0031] Furthermore, in some embodiments of the present invention, the power capacitor charging branch 30 further includes a first capacitor C1, one end of which is connected to the first input terminal of the grid-connected energy storage inverter 70, and the other end of which is connected to the second input terminal of the grid-connected energy storage inverter 70.

[0032] Specifically, in this embodiment, the first capacitor C1 is the bus capacitor of the grid-connected energy storage inverter 70. Its positive terminal is connected to the positive input terminal of the internal power circuit of the grid-connected energy storage inverter 70, and its negative terminal is connected to the negative input terminal of the power circuit. The first capacitor C1 is used to store electrical energy, stabilize the bus voltage, and provide energy for the subsequent power circuit.

[0033] Furthermore, in some embodiments of the present invention, the auxiliary power charging branch 40 includes a second thermistor PTC2, a first diode D1, and a second diode D2. The anode of the first diode D1 is connected to the first output terminal of the switching module 20, the cathode of the first diode D1 is connected to one end of the second thermistor PTC2, the other end of the second thermistor PTC2 is connected to the positive terminal of the auxiliary power supply 80, the cathode of the second diode D2 is connected to the second output terminal of the switching module 20, and the anode of the second diode D2 is connected to the negative terminal of the auxiliary power supply 80.

[0034] Specifically, in this embodiment, the first diode D1 and the second diode D2 are used to ensure unidirectional current flow and prevent current from flowing back into other branches. The second thermistor PTC2 is used to provide current-limiting protection for the auxiliary power supply charging branch 40. When the system starts up, the current flows through the first diode D1 and the second thermistor PTC2 to the auxiliary power supply 80 to charge it, and then returns to the negative DC bus through the second diode D2, forming a complete charging circuit. When an abnormal overcurrent occurs in the auxiliary power supply charging branch 40, the resistance of the second thermistor PTC2 increases sharply, limiting the fault current and achieving fault isolation.

[0035] Furthermore, in some embodiments of the present invention, the auxiliary power charging branch 40 further includes a second capacitor C2, one end of which is connected to the positive terminal of the auxiliary power supply 80, and the other end of which is connected to the negative terminal of the auxiliary power supply 80.

[0036] Specifically, in this embodiment, the second capacitor C2 is used to filter and store energy in the input voltage of the auxiliary power supply 80, ensuring that the auxiliary power supply 80 obtains a stable operating voltage and improving the power supply quality.

[0037] Furthermore, in some embodiments of the present invention, the decoupling branch 50 includes a third diode D3 and a fourth diode D4. The cathode of the third diode D3 is connected to the positive terminal of the auxiliary power supply 80, the anode of the third diode D3 is connected to the first input terminal of the grid-connected energy storage inverter 70, the anode of the fourth diode D4 is connected to the negative terminal of the auxiliary power supply 80, and the cathode of the fourth diode D4 is connected to the second input terminal of the grid-connected energy storage inverter 70.

[0038] Specifically, in this embodiment, the third diode D3 and the fourth diode D4 constitute a decoupling circuit. During normal operation, since the anode potential of the third diode D3 (the positive terminal potential of the first capacitor C1) is typically higher than its cathode potential (the positive terminal potential of the auxiliary power supply 80), the third diode D3 is reverse-biased and does not conduct. Similarly, the cathode potential of the fourth diode D4 (the negative terminal potential of the first capacitor C1) is lower than its anode potential (the negative terminal potential of the auxiliary power supply 80), and the fourth diode D4 is also reverse-biased. Therefore, during normal operation, the decoupling branch 50 does not participate in current flow.

[0039] When a short circuit fault occurs in the power capacitor charging branch 30, causing a short circuit in the first capacitor C1, the positive terminal potential of the first capacitor C1 is pulled down to near the negative terminal potential. At this time, the anode potential of the third diode D3 drops sharply, while the cathode potential is still maintained by the auxiliary power supply 80. The third diode D3 remains reverse biased, thus isolating the auxiliary power supply 80 from the short circuit fault point. Similarly, the fourth diode D4 also remains reverse biased. In this way, even if a severe short circuit occurs in the power capacitor charging branch 30, the auxiliary power supply charging branch 40 can still independently maintain the power supply to the auxiliary power supply 80, achieving fault decoupling.

[0040] With the cooperation of the above branches, the soft-start protection circuit 100 of this embodiment of the invention can maintain the power supply of the auxiliary power supply 80 when the whole machine fails, ensure that the controller does not lose power, realize fault self-locking and fault information reporting, and at the same time realize multiple protections through thermistors and diodes to prevent the fault from spreading and component damage.

[0041] During normal startup: When the system is not powered on, the first relay RLY1 and the second relay RLY2 are normally closed. After the AC power grid 60 is connected, the grid voltage is rectified into a DC peak by the rectifier module 10, and flows into the power capacitor charging branch 30 and the auxiliary power charging branch 40 through the closed relays RLY1 and RLY2, respectively.

[0042] In the power capacitor charging branch 30, the current sequentially charges the first capacitor C1 through the first thermistor PTC1 and the first resistor R1, while another path forms a charging circuit through the second resistor R2. The first thermistor PTC1, the first resistor R1, and the second resistor R2 together serve to limit the current and prevent excessive inrush current to the first capacitor C1.

[0043] In the auxiliary power charging branch 40, current sequentially charges the second capacitor C2 through the first diode D1 and the second thermistor PTC2, thus supplying power to the auxiliary power supply 80. The second diode D2 forms a current return path. The second thermistor PTC2 provides current limiting protection for the auxiliary power charging circuit.

[0044] Once the voltage of the first capacitor C1 is established, the auxiliary power supply 80 receives its operating voltage, and the controller (such as a DSP) powers on and starts. The controller activates the power circuit inside the grid-connected energy storage inverter 70, which maintains the voltage of the first capacitor C1. Subsequently, according to safety regulations, the controller disconnects the first relay RLY1 and the second relay RLY2, isolating the soft-start circuit from the power grid, and the system enters normal operating mode.

[0045] During the fault self-locking protection process: When a power module (e.g., DC-DC power module, MPPT power module, INV / PFC power module) inside the grid-connected energy storage inverter 70 fails, causing a short circuit in the first capacitor C1, the circuit of this invention implements the following protection action: First, the voltage sampling circuit detects a sudden drop in voltage across the first capacitor C1 and sends the fault information back to the controller. The controller quickly diagnoses the problem and immediately shuts down the power circuit to prevent the fault from spreading further.

[0046] Meanwhile, due to the existence of decoupling branch 50, the third diode D3 and the fourth diode D4 electrically decouple the power capacitor charging branch 30 from the auxiliary power supply charging branch 40. When the first capacitor C1 is short-circuited, the short-circuit fault will not affect the positive terminal of the auxiliary power supply 80 because the third diode D3 is reverse-biased; similarly, the fourth diode D4 is reverse-biased, protecting the negative terminal of the auxiliary power supply 80. Therefore, the auxiliary power supply charging branch 40 can independently maintain the power supply to the auxiliary power supply 80, and the auxiliary power supply 80 will not lose power.

[0047] After diagnosing the fault, the controller immediately re-closes the first relay RLY1 and the second relay RLY2, allowing the power grid to continue supplying power to the auxiliary power charging branch 40 through the rectifier module 10, ensuring the continuous operation of the auxiliary power supply 80. In this way, the controller always remains powered on, enabling it to perform operations such as saving fault data, reporting fault status, and communicating with the host computer, thus preventing the system from completely losing control due to power failure.

[0048] Furthermore, if a fault causes prolonged overcurrent in the power capacitor charging branch 30, the resistance of the first thermistor PTC1 will increase sharply due to heat generation, limiting the fault current and protecting the first resistor R1 and the second resistor R2 from overheating and damage. Similarly, if an abnormal overcurrent occurs in the auxiliary power charging branch 40, the resistance of the second thermistor PTC2 will also increase, achieving fault isolation.

[0049] In summary, the soft-start protection circuit according to the embodiments of the present invention can isolate the auxiliary power charging branch from the fault point through the decoupling branch when a short circuit fault occurs in the power capacitor charging branch, maintain the continuous power supply of the auxiliary power supply, ensure that the controller does not lose power, realize fault self-locking and fault information reporting, avoid system loss of control, and at the same time prevent the components from overheating and being damaged due to the spread of the fault, thereby improving the reliability and safety of the circuit.

[0050] Figure 3 This is a flowchart illustrating the control method of the soft-start protection circuit according to an embodiment of the present invention.

[0051] Specifically, in some embodiments of the present invention, the grid-connected energy storage inverter is also connected to an energy storage device, such as... Figure 3 As shown, the control method of the soft-start protection circuit includes: S101, obtains the input voltage of the grid-connected energy storage inverter, the energy storage voltage of the energy storage device, the AC grid connection information, and the fault information of the soft-start protection circuit.

[0052] Specifically, in this embodiment, the input voltage refers to the voltage across the first capacitor C1 (i.e., the BUS voltage). The energy storage voltage refers to the output voltage of the photovoltaic module PV or the terminal voltage of the battery BAT. The access information is used to indicate whether the AC grid has been connected. The fault information is used to indicate whether the soft-start protection circuit is currently in normal mode or fault mode (such as power module failure, BUS short circuit, etc.).

[0053] S102 controls the switching module based on multiple factors including input voltage, energy storage voltage, access information, and fault information.

[0054] Specifically, in this embodiment, when the input voltage is less than or equal to a first preset voltage and the AC power grid is determined to be connected according to the access information, the control switch module is closed; this corresponds to the scenario where the system needs to draw power from the power grid to supply power to the system when it is initially powered on or when the power grid is restored.

[0055] When the input voltage is less than or equal to the first preset voltage and the AC power grid is not connected according to the access information, the control switch module is disconnected; at this time, the power grid is not connected, and even if the BUS voltage is low, it cannot draw power from the power grid, and the relay should remain disconnected.

[0056] When the input voltage is greater than the first preset voltage and the energy storage voltage is greater than or equal to the second preset voltage, the control switch module is disconnected; at this time, the BUS voltage has been established and the photovoltaic or battery has sufficient energy, and the system can be powered by the internal source without closing the relay.

[0057] When the input voltage is greater than the first preset voltage, the energy storage voltage is less than the second preset voltage, and it is determined from the access information that the AC power grid is not connected, the control switch module is disconnected; at this time, the power grid is not connected, the internal energy source is insufficient, and the relay remains disconnected.

[0058] When the input voltage is greater than the first preset voltage, the energy storage voltage is less than the second preset voltage, the AC power grid is connected according to the access information, and the soft start protection circuit is in normal mode according to the fault information, the control switch module closes. Under this condition, although the system has established the BUS voltage, the internal source energy is insufficient, the power grid is connected, and the system has no fault, so it is necessary to close the relay to draw power from the power grid to maintain the auxiliary power supply.

[0059] When the input voltage is greater than the first preset voltage, the energy storage voltage is less than the second preset voltage, the AC power grid is confirmed to be connected based on the access information, and the soft-start protection circuit is determined to be in fault mode based on the fault information, the control switch module will disconnect. This operating condition corresponds to the system detecting a fault, but the BUS voltage is still higher than the threshold. In this case, the relay should be disconnected to prevent the fault's impact from escalating.

[0060] It should be noted that the specific values ​​of the first and second preset voltages can be set according to the actual application scenario, for example, they can be set to 250V, but the present invention is not limited thereto. In addition, the energy storage voltage can include both photovoltaic voltage and battery voltage. When either of these voltages is greater than or equal to the second preset voltage, the energy storage voltage is considered to meet the condition.

[0061] In summary, the control method of the soft-start protection circuit according to the embodiments of the present invention can isolate the auxiliary power charging branch from the fault point through the decoupling branch when a short circuit fault occurs in the power capacitor charging branch, maintain the continuous power supply of the auxiliary power supply, ensure that the controller does not lose power, realize fault self-locking and fault information reporting, avoid system loss of control, and at the same time prevent the components from overheating and being damaged due to the spread of the fault, thereby improving the reliability and safety of the circuit.

[0062] Based on the control method for the soft-start protection circuit proposed in the foregoing embodiments of the present invention, the present invention also proposes a computer-readable storage medium storing a control program for the soft-start protection circuit thereon. When the control program for the soft-start protection circuit is executed by a processor, it implements the control method for the soft-start protection circuit of the above embodiments of the present invention.

[0063] According to the computer-readable storage medium of the present invention, when a short circuit fault occurs in the power capacitor charging branch, the auxiliary power charging branch is isolated from the fault point by the decoupling branch, the auxiliary power supply is continuously supplied, the controller is not powered down, fault self-locking and fault information reporting are realized, the system is prevented from going out of control, and the overheating and damage of components caused by the fault propagation are prevented, thereby improving the reliability and safety of the circuit.

[0064] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0065] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0066] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," 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 the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0068] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0069] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0070] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0071] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A soft-start protection circuit, applied to a grid-connected energy storage inverter, characterized in that, include: A rectifier module, the input of which is connected to the AC power grid; A switching module, one end of which is connected to the output terminal of the rectifier module; A power capacitor charging branch, one end of which is connected to the other end of the switching module, and the other end of which is connected to the grid-connected energy storage inverter. An auxiliary power charging branch, one end of which is connected to the other end of the switch module, and the other end of which is connected to an auxiliary power source. A decoupling branch is connected between the other end of the power capacitor charging branch and the other end of the auxiliary power charging branch, and is used to decouple the auxiliary power charging branch from the power capacitor charging branch when the power capacitor charging branch is short-circuited.

2. The soft-start protection circuit according to claim 1, characterized in that, The output terminal of the rectifier module is connected to the positive DC bus and the negative DC bus respectively. The switching module includes at least one relay, which is connected to the positive DC bus or the negative DC bus and is used to control the on / off state of the DC bus.

3. The soft-start protection circuit according to claim 1, characterized in that, The power capacitor charging branch includes a first thermistor, a first resistor, and a second resistor. One end of the first thermistor is connected to the first output terminal of the switching module, and the other end of the first thermistor is connected to one end of the first resistor. The other end of the first resistor is connected to the first input terminal of the grid-connected energy storage inverter. One end of the second resistor is connected to the first output terminal of the switching module, and the other end of the second resistor is connected to the second input terminal of the grid-connected energy storage inverter.

4. The soft-start protection circuit according to claim 3, characterized in that, The power capacitor charging branch also includes a first capacitor, one end of which is connected to the first input terminal of the grid-connected energy storage inverter, and the other end of which is connected to the second input terminal of the grid-connected energy storage inverter.

5. The soft-start protection circuit according to claim 1, characterized in that, The auxiliary power charging branch includes a second thermistor, a first diode, and a second diode. The anode of the first diode is connected to the first output terminal of the switching module, the cathode of the first diode is connected to one end of the second thermistor, the other end of the second thermistor is connected to the positive terminal of the auxiliary power supply, the cathode of the second diode is connected to the second output terminal of the switching module, and the anode of the second diode is connected to the negative terminal of the auxiliary power supply.

6. The soft-start protection circuit according to claim 5, characterized in that, The auxiliary power charging branch also includes a second capacitor, one end of which is connected to the positive terminal of the auxiliary power supply, and the other end of which is connected to the negative terminal of the auxiliary power supply.

7. The soft-start protection circuit according to claim 1, characterized in that, The decoupling branch includes a third diode and a fourth diode. The cathode of the third diode is connected to the positive terminal of the auxiliary power supply, the anode of the third diode is connected to the first input terminal of the grid-connected energy storage inverter, the anode of the fourth diode is connected to the negative terminal of the auxiliary power supply, and the cathode of the fourth diode is connected to the second input terminal of the grid-connected energy storage inverter.

8. A control method applied to the soft-start protection circuit according to any one of claims 1-7, characterized in that, The grid-connected energy storage inverter is also connected to an energy storage device, and the method includes: The system acquires the input voltage of the grid-connected energy storage inverter, the energy storage voltage of the energy storage device, the access information of the AC power grid, and the fault information of the soft-start protection circuit. The switching module is controlled based on multiple factors, including the input voltage, the energy storage voltage, the access information, and the fault information.

9. The control method for the soft-start protection circuit according to claim 8, characterized in that, The switching module is controlled based on multiple factors including the input voltage, the energy storage voltage, the access information, and the fault information, including: When the input voltage is less than or equal to the first preset voltage and the AC power grid is determined to be connected according to the access information, the switch module is controlled to close. When the input voltage is less than or equal to the first preset voltage and it is determined from the access information that the AC power grid is not connected, the switch module is controlled to disconnect. When the input voltage is greater than the first preset voltage and the energy storage voltage is greater than or equal to the second preset voltage, the switching module is controlled to disconnect. When the input voltage is greater than the first preset voltage, the energy storage voltage is less than the second preset voltage, and it is determined from the access information that the AC power grid is not connected, the switch module is controlled to disconnect. When the input voltage is greater than the first preset voltage, the energy storage voltage is less than the second preset voltage, the AC power grid is determined to be connected according to the access information, and the soft start protection circuit is determined to be in normal mode according to the fault information, the switch module is controlled to close. When the input voltage is greater than the first preset voltage, the energy storage voltage is less than the second preset voltage, the AC power grid is determined to be connected according to the access information, and the soft-start protection circuit is determined to be in fault mode according to the fault information, the switching module is controlled to disconnect.

10. A computer-readable storage medium, characterized in that, It stores a control program for a soft-start protection circuit, which, when executed by a processor, implements the control method for the soft-start protection circuit according to any one of claims 8-9.

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