Energy storage converter control method

Abstract

The invention discloses an energy storage converter control method, which relates to the technical field of energy storage converters and is a method for monitoring the running state of an energy storage converter in real time and executing fault protection and / or state machine switching. The energy storage converter fault protection method comprises the following steps: reading a GPIO state or collecting a measurement value of each protection point, and comparing the measurement value with a fault threshold parameter to determine whether a fault occurs; when a fault occurs, a fault bit corresponding to the fault code register is activated, and the state machine is switched to a fault state and executes a fault protection program; the energy storage converter state machine switching method comprises the following steps: detecting whether a master control word register jumps or not compared with a previous period and executing corresponding operation; and executing corresponding control logic according to the current state of the state machine, wherein the states comprise a shutdown state, an alternating current pre-charging starting state, a standby state, an operation state, a fault state and a synchronous phase pulse test state. According to the method, the fault can be quickly responded, and the operation stability and safety of the PCS are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage converters, and in particular to a control method for an energy storage converter. Background Art

[0002] In the context of the current energy structure transformation and the intelligentization of the power system, energy storage technology is becoming increasingly important as a key link in balancing the supply and demand of the power grid and improving the utilization rate of renewable energy. As the core equipment connecting the energy storage device and the power grid, the power conversion system (PCS) is not only responsible for the two-way conversion of electric energy, but also directly affects the stability, power supply efficiency and safety of the power system. However, under actual operating conditions, PCS often faces various complex working conditions and external interference, which can easily lead to internal component aging, thermal runaway, circuit short circuit and other faults, thereby affecting the quality of the power output of the energy storage system. If not promptly investigated and handled, it will lead to problems such as shortened service life of the energy storage converter and abnormal output waveform.

[0003] Most of the existing fault protection mechanisms rely on single fault detection and simple isolation strategies, lacking the ability to identify and record fault types and respond quickly, which often leads to delayed or overly conservative protection measures, affecting system efficiency. At the same time, the efficiency of some existing PCS state switching processes is low, which can easily cause problems such as reduced reliability, voltage fluctuations, and current shocks, causing disturbances to the power grid. Therefore, it is particularly urgent to accurately diagnose and record the causes of PCS faults, achieve efficient state switching, and ensure stable system operation. Summary of the invention

[0004] In view of the above problems and technical requirements, the inventors have proposed a method for controlling an energy storage converter, which monitors the operating state of the energy storage converter in real time and performs fault protection and / or state machine switching. In the fault protection method, a fault diagnosis algorithm is used comprehensively to realize real-time monitoring of the operating state of the PCS and accurate fault diagnosis. By comparing and judging the result calculated by the algorithm with the current state of the fault code register, the fault type can be quickly identified, and the corresponding fault bit can be immediately activated to quickly switch to the fault protection program and shut down all related hardware control signals that may affect safety. In the state machine switching method, if the current main control word register changes the function bit compared with the state of the main control word register in the previous cycle, it means that a mode setting jump has occurred in the cycle, so that the corresponding function can be monitored and executed in real time. The present invention also improves the state machine switching program, and for different system states, conditional judgment is performed by comparing the current delay counter and output data with the preset threshold, and then the corresponding protection and state switching logic is automatically executed.

[0005] The technical solution of the present invention is as follows:

[0006] A method for controlling an energy storage converter, the method monitors the operating state of the energy storage converter in real time and executes fault protection and / or state machine switching.

[0007] The energy storage converter fault protection method comprises the following steps:

[0008] Read the GPIO status of the energy storage converter or collect the measured values ​​of each protection point as the input value for fault detection;

[0009] Determine whether a fault occurs by comparing the current input value with the fault threshold parameter;

[0010] When it is determined that a fault has occurred, the fault bit corresponding to the fault code register is activated, and the energy storage converter state machine switches to a fault state and executes a fault protection program;

[0011] The energy storage converter state machine switching method comprises the following steps:

[0012] Energy storage converter state machine initialization;

[0013] Detect whether the main control word register has changed compared with the previous cycle and perform corresponding operations;

[0014] Execute corresponding control logic according to the current state of the state machine, the states include shutdown state, AC pre-charge start state, standby state, running state, fault state and synchronous phase pulse test state;

[0015] Back up the current main control word register state to prepare for the next jump detection.

[0016] Its further technical solution is that, in the shutdown state, it will automatically record the number of abnormal shutdowns of the equipment, perform corresponding operations when receiving reset, test, parameter initialization, and AC pre-charge startup state switching instructions, turn off the fault indication and operation indication when the count value of the delay counter exceeds the threshold, and turn off all related hardware control signals, such as Figure 3 shown.

[0017] Its further technical solution is that during the AC pre-charge startup process, the pre-charge relay is turned on to pre-charge the DC side capacitor, a counter is used to control the execution process of the pre-charge, and a soft start flag is set, such as Figure 4 shown.

[0018] Its further technical solution is that, in the standby state, the startup instruction is mainly read from the main control word register and the main status word register, and the state machine is switched to the corresponding running state or shutdown state according to the delay counter, such as Figure 5 shown.

[0019] Its further technical solution is that, in the running state, when the count value of the restart delay counter exceeds the restart threshold, the restart flag bit of the main control word register is reset; when it is detected that the running bit of the main control word register is reset and exceeds the running delay threshold, the state machine is switched to the standby state, such as Figure 6 shown.

[0020] Its further technical solution is that, in the fault state, the system sets the energy storage converter control mode to the standby state and stops all current operation operations; activates the fault indication, turns off the operation indication and turns off the hardware control signal that may affect safety; when the reset bit of the main control word or main status word register is set, performs a comprehensive fault reset operation; after the system does not detect a new fault and delays for a period of time, switches the state machine to the shutdown state, such as Figure 7 shown.

[0021] Its further technical solution is that, in the synchronous phase pulse test state, when the stop bit of the main control word register is set or the flag bit of entering the test mode is an invalid value, the state machine is switched to the stop state; when the AC pre-charge delay counter exceeds the preset delay threshold, the pre-charge relay is turned off to ensure the safety of the test; after a delay of a period of time, the test mode is officially entered, the test bit of the main status word register is updated, and then the control mode of the energy storage converter control object is set to Udc_Q to start the test, such as Figure 8 shown.

[0022] The beneficial technical effects of the present invention are:

[0023] The present invention utilizes the characteristics of software that reads the internal state quantity data of the register quickly and accurately, and determines whether the PCS is overloaded, underloaded or delayed by calculating whether the current output data exceeds the fault threshold through function calls. Such execution logic can ensure that the PCS outputs good power quality and reduce the risks brought by abnormal fluctuations in voltage and current. And by comparing the function bits of the main state word register of the current cycle state machine with the state of the previous cycle, it can accurately and quickly respond to operations such as fault processing or parameter enabling. This ensures the operational stability and safety of the PCS to a large extent. The automatic execution protection logic of the present method effectively avoids system damage or efficiency reduction caused by response delays, reduces the reliance on manual intervention, and enables the system to operate stably under unattended or remote monitoring conditions, thereby improving operational efficiency and reducing labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of energy storage converter fault detection provided by this application.

[0025] Figure 2 This is a main program flow chart of the energy storage converter state machine switching provided by this application.

[0026] Figure 3 This is a flow chart of the state machine provided by this application for the shutdown state control logic.

[0027] Figure 4 The state machine provided in this application is a flow chart of the control logic of the AC pre-charging startup state.

[0028] Figure 5 This is a flow chart of the state machine provided by the present application for the control logic of the standby state.

[0029] Figure 6 The state machine provided in this application is a flow chart of the operating state control logic.

[0030] Figure 7 It is a flow chart of the state machine provided by the present application as the fault state control logic.

[0031] Figure 8 The state machine provided by the present application is a flow chart of the synchronous phase pulse test state control logic. DETAILED DESCRIPTION

[0032] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0033] An embodiment of the present application provides a method for controlling an energy storage converter, which monitors the operating state of the energy storage converter in real time and performs fault protection and / or state machine switching. Figure 1 As shown, the energy storage converter fault protection method includes the following steps:

[0034] Step 1: Read the fault threshold parameters of each protection point from the global parameter structure ParaData.FaultProtect, and configure the specific parameters of each protection mechanism accordingly. For example, for the protection point "total bus voltage overvoltage protection", the corresponding over-protection threshold is pre-set to 1500V (16-bit unsigned integer) in the system, and the over-protection delay threshold is 10 system cycles (16-bit unsigned integer). These two parameters can be modified and saved externally through communication and other means. At the same time, the system will reserve a flag bit corresponding to the protection point and a bit in the fault code register. When the measured value obtained by sampling exceeds the over-protection threshold and the delay exceeds the over-protection delay, it means that a fault has indeed occurred. Then mark the corresponding flag bit and set the corresponding fault position in the fault code register to 1 to show the cause of the fault. In this embodiment, the delay threshold is set to play a role in filtering and preventing false alarms, thereby proving that the fault has occurred for a period of time and is not an occasional sampling fault.

[0035] Step 2: Update the reset state of the current fault item according to the reset flag reset of the main status word register MswReg of the state machine, and perform a new fault detection cycle after the fault is reset. When the reset flag reset is set to 1, the fault is reset, and when it is set to 0, the fault state remains unchanged and the next detection cannot be performed.

[0036] Step 3: Read the GPIO status of the energy storage converter or collect the measured values ​​of each protection point as the input value of fault detection, call the calculation function of the overload and underload objects and pass in its own pointer, and determine whether a fault occurs by comparing the current input value with the fault threshold parameter.

[0037] Specifically, when the current input value is the measured value of the DC side and AC side protection point collected, it is compared with the high / low fault threshold. If it is greater than the high fault threshold, it is determined that the protection point has an overload fault. If it is less than the low fault threshold, it is determined that the protection point has an underload fault. When the current input value is the real-time voltage and current measurement value of the collected protection point, it is compared with the over-protection / under-protection threshold. If it is greater than the over-protection threshold and the delay exceeds the over-protection delay threshold, it is determined that the protection point has an over-protection fault. If it is less than the under-protection threshold and the delay exceeds the under-protection delay threshold, it is determined that the protection point has an under-protection fault.

[0038] Step 4: If the corresponding fault bit of the current fault code register (FaultCode0Reg to FaultCode4Reg) is not activated and the calculation result determines that a fault has occurred, the fault bit corresponding to the fault code register is activated, the cause of the fault is recorded, and the energy storage converter state machine switches to the fault state and executes the fault protection program.

[0039] Still taking overprotection as an example, for each overprotection monitoring item, there are the following parameters: Input: the measured value of the current input; GreatValue: the set overprotection threshold; cnt: delay counter; flag: flag structure. If the current input value (input) is greater than or equal to the set overprotection threshold (GreatValue), the delay counter cnt is accumulated. If the value of the counter is greater than or equal to the set action delay time (ActDealy), it means that the overprotection state has lasted for a certain period of time. Then the overprotection status bit (flag.Status) is set to 1, indicating that the overprotection condition has been detected. Reset the counter to the value of the action delay ActDealy, and keep the state until manually reset. Then the system will compare whether the fault bit in the fault code register of the previous cycle has a fault. If no fault occurred in the previous cycle and the overprotection condition is now found through calculation, the fault code register is updated and the fault cause is marked in the corresponding fault bit. If the reset flag bit (Reset) is set to 1, it means that the overprotection state needs to be reset, then the overprotection flag bit (flag.Status) is cleared, indicating that the overprotection state is released. And reset the counter cnt to 0 to prepare for the next detection.

[0040] Combination Figure 2 As shown, the energy storage converter state machine switching method includes the following steps:

[0041] Step 5: Call the energy storage converter state machine initialization function to initialize the state machine and related states, set the current state and previous state of the state machine to the stop state (Stop_State), and clear all fault code registers.

[0042] Step 6: Enter the state machine call function, detect whether the main control word register McwReg has jumped compared with the previous cycle and perform corresponding operations, specifically including: when it is detected that the zero calibration bit of the main control word register McwReg in the current cycle is set (set to 1), and it is not set (set to 0) in the previous cycle, perform ADC zero point calibration. When it is detected that the parameter enable bit of the main control word register McwReg in the current cycle is set (set to 1), and it is not set (set to 0) in the previous cycle, set the parameter enable bit of the main status word register MswReg to a valid value, which indicates that the system has accepted and enabled the new parameter setting, and reset the state machine status bit. When it is detected that any fault bit in the fault code register FaultCode0Reg to FaultCode4Reg is activated, the state machine is switched to the fault state, the fault flag bit of the main status word register MswReg is set to a valid value, and all normal operations are closed. Optionally, the valid value set in this embodiment is set to 1, and the following statements are similar.

[0043] Step 7: Next, use the conditional selection statement to execute the corresponding control logic according to the current state of the state machine RunData.StateMachine register. The states include shutdown state, AC pre-charge startup state, standby state, running state, fault state and synchronous phase pulse test state. If the current state of the state machine does not belong to the above conditions, it will enter the shutdown state by default to ensure system safety. In this embodiment, the RunData.StateMachine register is the current final state of the PCS, and the main state word register MswReg is equivalent to an intermediate variable. On the one hand, the value of the system main state word register of the previous cycle can be saved and compared with the value of the main state word register of the current cycle to capture a certain jump of the system; on the other hand, when the system switches states, multiple states may appear at the same time. At this time, MswReg can be used as an intermediate variable to quickly perform operations such as reset to avoid errors in the state displayed by the system. The main control word register McwReg mainly represents operation instructions, such as charging, parameter enable, etc.

[0044] Step 8: After executing the corresponding logic, back up the current main control word register McwReg state PreMcwReg=McwReg to prepare for the next jump detection.

[0045] Step 9: Figure 3 As shown, in the shutdown state, if the current state machine state is the shutdown state and the previous state is the fault state, the restart counter restart count value is increased. This counter is used to automatically record the number of abnormal shutdowns of the device and save the current state to StateMachinepre, which is used to record the previous cycle state of the state machine. If a reset command is received, the restart counter restart is reset; if a test mode entry command is received, the state machine switches to the test mode.

[0046] Step 10: Use the delay counter dlyLED to record the shutdown duration. After the count value of the delay counter dlyLED exceeds 10 cycles, turn off the fault indication and operation indication, turn off all related hardware control signals, and reset the delay counter dlyLED. Among them, the hardware control signals include: DC positive and negative contactor control signals, pre-charge relay control signals, AC1, AC2 main circuit relay control signals, and main AC contactor voltage switching control signals.

[0047] Step 11: When the parameter bit in the main control word register McwReg is set to 1, call the Parameter_init() function to initialize the parameters. When the start bit bits.Start of the main status word register MswReg is activated, set the state machine state to ReadyStart, ready to enter the pre-charge startup process.

[0048] Step 12: In the shutdown state, clear the reset bits in the main control word register McwReg and the main status word register MswReg, indicating that the reset action is completed. At the same time, clear the stop bit in the main control word register McwReg, indicating that the shutdown command is canceled. Set multiple status bits (standby RdyRun, running Running, test mode TestMode, fault Fault, pre-charge Charging) to 0 to ensure that in the shutdown state, all running, testing and fault states are correctly reset and the system is in the initial state.

[0049] Step 13: Figure 4 As shown, in the AC pre-charging start-up state, the pre-charging relay is turned on to pre-charge the DC side capacitor, and a counter is used to control the execution process of the pre-charging. Specifically, the pre-charging relay and the DC negative contactor are turned on, and the delay counter dly is started to track the duration of the pre-charging process. When the DC voltage reaches more than 94% of the battery voltage and exceeds the predetermined voltage of 500V, the DC positive contactor is turned on to complete the circuit closure on the DC side, and the pre-charging delay counter dly_Precharge is started to control the duration of the pre-charging. When the count value of the pre-charging delay counter dly_Precharge is greater than 400 cycles, the pre-charging relay is turned off, and the soft start flag bit of the main control word register McwReg is set to a valid value, indicating that the energy storage converter is in a soft start state. At this time, the DC total bus voltage has stabilized and is basically consistent with the battery voltage, and it is considered that the pre-charging state has ended.

[0050] Step 14: When the energy storage converter control mode is off-grid or island mode, turn on the main circuit relays (AC1 and AC2), switch the state machine to the standby state, reset the soft start flag of the main status word register MswReg to 0, and reset the dly and dly_Precharge counters.

[0051] Step 15: After the pre-charging stage, when the total delay of the soft start process exceeds the set threshold (i.e., dly exceeds 1000 cycles) and the absolute value of the difference between the output voltage of the energy storage converter and the grid voltage is less than the set voltage threshold of 15V, the main circuit relay is turned on and the count value of the charging delay counter dly_Charging is increased. When the count value of dly_Charging is greater than 6 cycles, the state machine is switched to the standby state, and the soft start flag bit of the main status word register MswReg is reset to 0, and the dly, dly_Precharge and dly_Charging counters are reset.

[0052] Step 16: When the total delay of the soft start process exceeds the maximum set threshold (i.e., dly exceeds 8000 cycles), the state machine is switched to the fault state, and the fault bit corresponding to the fault code register is activated. For example, the soft charging error flag is set in the fault code register FaultCode3Reg to mark that the fault is caused by the soft charging process. At the same time, the main circuit relay is closed and the dly counter is reset.

[0053] Step 17: Set the soft start flag bit Charge of the main control word register McwReg to 0, indicating that the startup operation has been completed. Set multiple status bits (standby RdyRun, running Running, test mode TestMode, fault Fault) of the main status word register MswReg to 0 to ensure that in the pre-charge soft start state, all running, testing and fault states are correctly reset and the system is in the initial state.

[0054] Step 18: Figure 5 As shown, in the standby state, the delay counter dly is incremented in each cycle to track the duration of the standby state.

[0055] Step 19: Read the start instruction from the main control word register McwReg and the main status word register MswReg, and switch the state machine to the corresponding running state or shutdown state according to the delay counter. Specifically, when the run bit InvRun in the main control word register McwReg is 1 and the dly count value exceeds 650 cycles, the state machine is switched to the running state and the dly counter is reset, which indicates that the system is ready to switch from standby to operation. When the start bit Start of the main status word register MswReg is reset to 0 and the dly count value exceeds 200 cycles, the state machine is switched back to the shutdown state and the dly counter is reset, which indicates that the start instruction did not last long enough or was withdrawn, and the system should return to the shutdown state.

[0056] Step 20: Set the RdyRun bit in the main status word register MswReg to 1, indicating that the system is ready to run, and clear the run, fault, test and charge status bits to ensure that these states are not mislabeled in the standby state.

[0057] Step 21: Figure 6 As shown in the figure, in the running state, the restart delay counter dly_restart is increased in each cycle. When the count value of dly_restart exceeds 60,000 cycles, the dly_restart counter and the restart flag bit restart of the main control word register McwReg are reset to control the automatic restart logic. The contactor delay counter dlycon is incremented in each cycle to calculate the duration of contactor closure. It is reset to 0 in the stop state and incremented in the running state.

[0058] Step 22: When the run bit of the main control word register McwReg is detected to be reset to 0, the run delay counter dlyrun is incremented. If dlyrun exceeds 50 cycles, the state machine is switched to the standby state, indicating that the system has switched from the run state to the standby state, waiting for a new start command, and the dlyrun counter is reset.

[0059] Step 23: Set the running bit Running of the main status word register MswReg to 1, indicating that the system is in the running state, and clear the standby, fault, test and charging status bits to ensure the accuracy and consistency of the status marking.

[0060] Step 24: Figure 7 As shown, in the fault state, the energy storage converter control mode is set to standby and all current operations are stopped to enter a safe state. The fault indication is activated, the operation indication is turned off, and all related hardware control signals are turned off to ensure that the system is disconnected from the power supply in the fault state, thereby ensuring system safety and the stability of power quality.

[0061] Step 25: The fault delay counter dlyfault is increased in each cycle to record the duration of the fault. When the reset bit (reset) of the main status word register MswReg is set to 1, a comprehensive fault reset operation is performed, including clearing the fault code register, the fault flags of each temperature module (including modules A to F, the temperature of the ambient temperature SCR module, to reset the fault status related to temperature monitoring), the undervoltage flag in McwReg, and then resetting the dlyfault counter to prepare for restart or recovery. When the reset bit (reset) of the main control word register McwReg is set to 1, the same comprehensive fault reset operation is also performed, including setting the reset bit (reset) of MswReg to 1, and then resetting the dlyfault counter and the restart counter.

[0062] Step 26: Back up the current state machine state to StateMachinepre. If all fault code registers are restored to 0, it means that no fault is currently detected. At this time, each time a cycle is passed, the fault delay timer (dlyfault1) increments. When the count value of dlyfault1 exceeds 5 cycles, the state machine switches to the shutdown state and resets dlyfault1, indicating that it enters the safe shutdown state after no new fault is detected for a period of time.

[0063] Step 27: Clear the running, stopping, and charging status bits in the main control word register McwReg to ensure that there are no active control instructions and prepare for state transition. Update the fault bit in the main status word register MswReg to 1 to clearly indicate that the current state of the system is a fault state, and clear the standby, running, test, and charging status bits in MswReg to ensure that these states are not mislabeled in the fault state.

[0064] Step 28: Figure 8 As shown, in the synchronous phase pulse test state, when the stop bit Stop of the main control word register McwReg is set to 1 or the flag bit for entering the test mode is an invalid value (that is, the EnterTestMode bit is 0), the state machine is switched to the stop state, and the AC pre-charge start delay counter dly is cleared, indicating that the test process is interrupted and returned to the stop state.

[0065] Step 29: Control the pre-charge relay according to the value of the start delay counter dly: When the count value of dly is not greater than 100 cycles, turn on the pre-charge relay. This step is used to pre-charge the system briefly before the test starts to ensure the safe startup of the power electronic equipment. When the count value of dly exceeds 100 cycles, turn off the pre-charge relay, indicating that the pre-charge stage is over, which is intended to protect the system from overcharging and prepare for the next test.

[0066] Step 30: When the count value of dly is greater than 300 cycles, it indicates that the preset delay time is sufficient, and the system performs the following operations to prepare to enter the test mode: update the test bit of the main status word register MswReg (that is, TestMode is set to 1), and set the control mode of the energy storage inverter control object to Udc_Q, which instructs the PCS to start testing with the DC bus voltage as the control target.

[0067] Step 31: Clear multiple status flags in the main status word register MswReg, including standby, running, fault and charging status bits, indicating that the system ensures that all status identifiers are correctly initialized before entering the test mode to create a correct initial condition for the test.

[0068] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0069] The above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A method for controlling an energy storage converter, characterized in that: The method monitors the operating state of the energy storage converter in real time and performs fault protection and / or state machine switching; Among them, the energy storage converter fault protection method includes: Read the GPIO status of the energy storage converter or collect the measured values ​​of each protection point as the input value for fault detection; Determine whether a fault occurs by comparing the current input value with the fault threshold parameter; When it is determined that a fault has occurred, the fault bit corresponding to the fault code register is activated, and the energy storage converter state machine switches to a fault state and executes a fault protection program; Among them, the energy storage converter state machine switching method includes: Energy storage converter state machine initialization; Detect whether the main control word register has changed compared with the previous cycle and perform corresponding operations; Execute corresponding control logic according to the current state of the state machine, wherein the state includes shutdown state, AC pre-charge start state, standby state, running state, fault state and synchronous phase pulse test state; Back up the current main control word register state to prepare for the next jump detection.

2. The energy storage converter control method according to claim 1, characterized in that: Determining whether a fault occurs by comparing the current input value with the fault threshold parameter includes: When the current input value is the measured value of the collected DC side and AC side protection points, it is compared with the fault high / low threshold. If it is greater than the fault high threshold, it is determined that the protection point has an overload fault. If it is less than the fault low threshold, it is determined that the protection point has an underload fault. When the current input value is the real-time voltage and current measurement value of the collected protection point, it is compared with the over-protection / under-protection threshold. If it is greater than the over-protection threshold and the delay exceeds the over-protection delay threshold, it is determined that the protection point has an over-protection fault. If it is less than the under-protection threshold and the delay exceeds the under-protection delay threshold, it is determined that the protection point has an under-protection fault.

3. The energy storage converter control method according to claim 1, characterized in that: The detecting whether the main control word register has a jump compared with the previous cycle and performing a corresponding operation includes: When it is detected that the zero calibration bit of the main control word register in the current cycle is set, and it was not set in the previous cycle, the ADC zero point calibration is performed; When it is detected that the parameter enable bit of the main control word register in the current cycle is set and was not set in the previous cycle, the parameter enable bit of the main status word register is set to a valid value and the state machine state bit is reset; When it is detected that any fault bit of the fault code register is activated, the state machine is switched to the fault state, the fault flag bit of the main status word register is set to a valid value, and all normal operations are closed.

4. The energy storage converter control method according to claim 1, characterized in that: The control logic executed by the state machine when it is in the shutdown state includes: Automatically record the number of abnormal shutdowns of the equipment in the shutdown state; Execute corresponding operations upon receiving reset, test, parameter initialization, and AC pre-charge start state switching instructions; When the count value of the delay counter exceeds a set threshold, the fault indication and the operation indication are turned off, all related hardware control signals are turned off, and the delay counter is reset; The hardware control signals include: DC positive and negative contactor control signals, pre-charging relay control signals, main circuit relay control signals, and main AC contactor voltage switching control signals.

5. The energy storage converter control method according to claim 1, characterized in that: The state machine is the control logic executed in the AC pre-charging start-up state, including: In the AC pre-charging start-up state, the pre-charging relay is turned on to pre-charge the DC side capacitor, and a counter is used to control the execution process of the pre-charging; When the energy storage converter control mode is off-grid or island mode, the main circuit relay is turned on, the state machine is switched to the standby state, and the relevant counters and flags are reset; When the total delay of the soft start process exceeds the set threshold and the absolute value of the difference between the output voltage of the energy storage converter and the grid voltage is less than the set voltage threshold, the main circuit relay is turned on and the count value of the charging delay counter is increased; when the count value of the charging delay counter is greater than the set threshold, the state machine is switched to the standby state and the relevant counters and flags are reset; When the total delay of the soft start process exceeds the maximum set threshold, the state machine is switched to the fault state, the fault bit corresponding to the fault code register is activated, and the main circuit relay is turned off.

6. The energy storage converter control method according to claim 5, characterized in that: The process of starting the pre-charging relay to pre-charge the DC side capacitor and using a counter to control the pre-charging includes: Turn on the pre-charging relay and the DC negative contactor, and start the delay counter to track the duration of the pre-charging process; When the DC voltage reaches p% of the battery voltage and exceeds the predetermined voltage value, the DC positive contactor is turned on to complete the circuit closure on the DC side, and the pre-charge delay counter is started to control the duration of the pre-charge; When the count value of the pre-charge delay counter is greater than a set threshold, the pre-charge relay is turned off, and the soft start flag bit of the main control word register is set to a valid value, indicating that the energy storage converter is in a soft start state.

7. The energy storage converter control method according to claim 1, characterized in that: The control logic executed when the state machine is in the standby state includes: In the standby state, a start instruction is read from the main control word register and the main status word register, and the state machine is switched to a corresponding running state or a shutdown state according to a delay counter.

8. The energy storage converter control method according to claim 1, characterized in that: The control logic executed when the state machine is in the running state includes: In the running state, when the count value of the restart delay counter exceeds the set restart threshold, the restart delay counter and the restart flag bit of the main control word register are reset; When it is detected that the operation bit of the main control word register is reset and exceeds the operation delay threshold, the state machine is switched to the standby state.

9. The energy storage converter control method according to claim 1, characterized in that: The control logic executed by the state machine when it is in the fault state includes: In the fault state, the energy storage converter control mode is set to a standby state and all current operations are stopped; Activate the fault indication, turn off the operation indication and all related hardware control signals, including: DC positive and negative contactor control signals, pre-charge relay control signals, main circuit relay control signals, and main AC contactor voltage switching control signals; When the reset bit of the main control word register or the main status word register is set, a comprehensive fault reset operation is performed, including clearing the fault code register, the fault flag of each temperature module, and the undervoltage flag; If no new fault is detected within a period of time, the state machine is switched to the shutdown state.

10. The energy storage converter control method according to claim 1, characterized in that: The control logic executed when the state machine is in the synchronous phase pulse test state includes: In the synchronous phase pulse test state, when the stop bit of the main control word register is set or the flag bit of entering the test mode is an invalid value, the state machine is switched to the stop state; When the AC pre-charge delay counter exceeds the preset delay threshold, the pre-charge relay is turned off; After a delay of a period of time, the test mode is officially entered, the test bit of the main status word register is updated, the control mode of the energy storage converter control object is set to take the DC bus voltage as the control target, and the test begins.

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