Abnormal detection method, energy storage device and storage medium

Abstract

The present application relates to the field of circuit technology, and in particular to an abnormality detection method, energy storage device, and storage medium. The abnormality detection method includes: when the bus voltage of the DC bus is equal to or greater than a first voltage threshold, outputting a preset control signal to control the power conversion module to enter an open-loop no-load state; detecting the capacitor voltage and / or inductor current in the power conversion module in the open-loop no-load state to obtain a first detection result; when the first detection result is abnormal, outputting a first prompt message, the first prompt message being used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal. The abnormality detection method in the present application, by performing abnormality detection on the power conversion module in the open-loop no-load state, can avoid the sampling circuit in the photovoltaic energy storage circuit from being affected by the load, and can timely and accurately determine whether the sampling circuit is abnormal, thereby effectively improving the accuracy of abnormality detection of the photovoltaic energy storage circuit.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to an abnormality detection method, an energy storage device, and a storage medium. Background Art

[0002] A photovoltaic energy storage circuit is a circuit within an energy storage device that stores energy based on the photovoltaic array. The proper operation of the photovoltaic energy storage circuit is crucial to the device's ability to store energy properly. Currently, when powering up an energy storage device, voltage or current sampling is typically performed on the photovoltaic energy storage circuit. The sampled voltage or current is then used to determine if an anomaly is occurring in the photovoltaic energy storage circuit. However, during the startup process, the sampling circuit within the photovoltaic energy storage circuit is often affected by the load, resulting in inaccurate voltage or current sampling, which in turn reduces the accuracy of detecting anomalies in the photovoltaic energy storage circuit. Therefore, improving the accuracy of photovoltaic energy storage circuit anomaly detection has become a pressing issue. Summary of the Invention

[0003] The present application provides an abnormality detection method, energy storage device and storage medium. By performing abnormality detection on a power conversion module in an open-loop no-load state, the sampling circuit can be prevented from being affected by the load, and whether the sampling circuit is abnormal can be determined in a timely and accurate manner, thereby effectively improving the accuracy of abnormality detection in the photovoltaic energy storage circuit.

[0004] In a first aspect, the present application provides an abnormality detection method for performing abnormality detection on a photovoltaic energy storage circuit, wherein the photovoltaic energy storage circuit includes a boost module and a power conversion module, wherein the first end of the boost module is used to connect to a photovoltaic array, the second end of the boost module is used to connect to the first end of the power conversion module via a DC bus, and the second end of the power conversion module is used to connect to a load; the method includes: when the bus voltage of the DC bus is equal to or greater than a first voltage threshold, outputting a preset control signal to control the power conversion module to enter an open-loop no-load state; detecting the capacitor voltage and / or inductor current in the power conversion module in the open-loop no-load state to obtain a first detection result; when the first detection result is abnormal, outputting a first prompt information, wherein the first prompt information is used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0005] In a second aspect, the present application also provides an energy storage device, which includes a memory, a processor and a photovoltaic energy storage circuit; the memory is used to store a computer program; the processor is used to execute the computer program and implement the above-mentioned anomaly detection method when executing the computer program.

[0006] In a third aspect, the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor implements the above-mentioned anomaly detection method.

[0007] The present application discloses an abnormality detection method, energy storage device and storage medium. The method includes: when the bus voltage of a DC bus is equal to or greater than a first voltage threshold, outputting a preset control signal to control a power conversion module to enter an open-loop no-load state, thereby controlling the power conversion module to enter an open-loop no-load state when a photovoltaic energy storage circuit is turned on; by detecting the capacitor voltage and / or inductor current in the power conversion module in the open-loop no-load state, the sampling circuit in the photovoltaic energy storage circuit can be prevented from being affected by the load, and timely and accurate determination of whether the sampling circuit is abnormal can be achieved, thereby effectively improving the accuracy of abnormality detection of the photovoltaic energy storage circuit; by outputting first prompt information for indicating that the sampling circuit of the photovoltaic energy storage circuit is abnormal when a first detection result is abnormal, the user can be promptly reminded that the sampling circuit of the photovoltaic energy storage circuit has an abnormality. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0009] Figure 1 This is a schematic structural diagram of an energy storage device provided in an embodiment of the present application;

[0010] Figure 2 This is a schematic structural diagram of a photovoltaic energy storage circuit provided in an embodiment of the present application;

[0011] Figure 3 This is a circuit diagram of a photovoltaic energy storage circuit provided in an embodiment of the present application;

[0012] Figure 4 is a schematic flow chart of an anomaly detection method provided in an embodiment of the present application;

[0013] Figure 5 is a schematic flow chart of another anomaly detection method provided in an embodiment of the present application;

[0014] Figure 6 This is a schematic flowchart of another anomaly detection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0016] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, combined, or partially merged, so the actual execution order may vary depending on the actual situation.

[0017] It should be understood that the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0018] It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0019] Embodiments of the present application provide an anomaly detection method, energy storage device, and storage medium. The anomaly detection method can be applied to energy storage devices. By detecting anomalies in a power conversion module in an open-loop, no-load state, the sampling circuit in a photovoltaic energy storage circuit can be prevented from being affected by the load, enabling timely and accurate determination of whether the sampling circuit is abnormal, thereby effectively improving the accuracy of anomaly detection in the photovoltaic energy storage circuit.

[0020] Among them, the energy storage device can be a mobile energy storage device, a household energy storage device, or an energy storage device installed on a vehicle.

[0021] See also Figure 1 , Figure 1 This is a schematic diagram of the structure of an energy storage device 10 provided in an embodiment of the present application. Figure 1 As shown, the energy storage device 10 may include a processor 11, a memory 12 and a photovoltaic energy storage circuit 13, wherein the processor 11, the memory 12 and the photovoltaic energy storage circuit 13 may be connected via a bus, such as any applicable communication bus such as an I2C (Inter-integrated Circuit) bus.

[0022] The photovoltaic energy storage circuit 13 is used to store the electrical energy input from the photovoltaic array in the battery module of the energy storage device 10, and is also used to output the electrical energy input from the photovoltaic array to the load. In addition, the photovoltaic energy storage circuit 13 is also used to output the electrical energy of the battery module to the load.

[0023] The memory 12 may include a storage medium and an internal memory. The storage medium may store an operating system and a computer program. The computer program includes program instructions that, when executed, cause the processor to execute the anomaly detection method.

[0024] The processor 11 is used to provide computing and control capabilities to support the operation of the entire energy storage device 10 .

[0025] The processor 11 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. A general-purpose processor may be a microprocessor or any conventional processor.

[0026] In one embodiment, when executing a related computer program, the processor 11 is configured to perform abnormality detection on a photovoltaic energy storage circuit. The photovoltaic energy storage circuit includes a boost module and a power conversion module. A first end of the boost module is configured to be connected to a photovoltaic array, a second end of the boost module is configured to be connected to a first end of the power conversion module via a DC bus, and a second end of the power conversion module is configured to be connected to a load. Specifically, the processor 11 is configured to run a computer program stored in the memory 12 to implement the following steps:

[0027] When the bus voltage of the DC bus is equal to or greater than a first voltage threshold, a preset control signal is output to control the power conversion module to enter an open-loop no-load state; the capacitor voltage and / or the inductor current in the power conversion module in the open-loop no-load state are detected to obtain a first detection result; when the first detection result is abnormal, a first prompt information is output, and the first prompt information is used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0028] In one embodiment, the power conversion module includes a three-phase three-level inverter circuit, and each phase three-level inverter circuit includes a capacitor and an inductor; when the processor 11 detects the capacitor voltage and / or the inductor current in the power conversion module in an open-loop no-load state and obtains a first detection result, it is configured to implement:

[0029] Obtaining a capacitor voltage corresponding to each phase of the three-level inverter circuit, detecting the capacitor voltage, and obtaining the first detection result; and / or obtaining an inductor current corresponding to each phase of the three-level inverter circuit, detecting the inductor current, and obtaining the first detection result.

[0030] In one embodiment, the processor 11 is further configured to implement:

[0031] Determine a first voltage difference between the capacitor voltage and a reference voltage, where the reference voltage is the capacitor voltage of each phase of the three-level inverter circuit when the power conversion module is in a normal state and under the control of the preset control signal; when the absolute value of the first voltage difference is greater than a second voltage threshold, determine that the first detection result is abnormal.

[0032] In one embodiment, the photovoltaic energy storage circuit further includes a switch module, and the second end of the power conversion module is connected to the load through the switch module; when the processor 11 outputs a preset control signal to control the power conversion module to enter an open-loop no-load state, it is used to implement:

[0033] The switch module is controlled to disconnect the power conversion module from the load, and open-loop control is performed on the on-off of each switch unit in the power conversion module based on the preset control signal.

[0034] In one embodiment, a bus capacitor is provided on the DC bus; and the processor 11 is further configured to implement:

[0035] Controlling each boost unit in the boost module and each switch unit in the power conversion module to turn off so that the input voltage of the photovoltaic array charges the bus capacitor; performing abnormality detection based on the input voltage and the capacitor voltage of the bus capacitor to obtain a second detection result; when the second detection result is abnormal, outputting a second prompt information, the second prompt information being used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0036] In one embodiment, when performing abnormality detection based on the output voltage and the capacitor voltage of the bus capacitor to obtain the second detection result, the processor 11 is configured to implement:

[0037] Determine a second voltage difference between the output voltage and the capacitor voltage of the bus capacitor; and determine that the second detection result is abnormal when an absolute value of the second voltage difference is greater than a third voltage threshold.

[0038] In one embodiment, the photovoltaic energy storage circuit further includes an energy storage module, and the energy storage module is connected to the DC bus; the processor 11 is further configured to implement:

[0039] Obtain a first detection voltage of the energy storage module, where the first detection voltage is the bus voltage of the DC bus detected by the energy storage module; obtain a second detection voltage of the power conversion module, where the second detection voltage is the bus voltage of the DC bus detected by the power conversion module; perform abnormality detection based on the first detection voltage and the second detection voltage to obtain a third detection result; when the third detection result is abnormal, output third prompt information, where the third prompt information is used to prompt that a sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0040] In one embodiment, when performing abnormality detection based on the first detection voltage and the second detection voltage to obtain a third detection result, the processor 11 is configured to implement:

[0041] Determine a third voltage difference between the first detection voltage and the second detection voltage; and determine that the third detection result is abnormal when an absolute value of the third voltage difference is greater than a fourth voltage threshold.

[0042] See also Figure 2 , Figure 2 This is a schematic diagram of the structure of a photovoltaic energy storage circuit 13 provided in an embodiment of the present application. Figure 2 As shown, the photovoltaic energy storage circuit 13 may include a boost module 130 , a DC bus 131 , a power conversion module 132 , a switch module 133 and an energy storage module 134 .

[0043] like Figure 2 As shown, a first end of the boost module 130 is connected to the photovoltaic array 14, a second end of the boost module 130 is connected to a first end of the power conversion module 132 via a DC bus 131, and a second end of the power conversion module 132 is connected to a load 15. The load 15 can be an AC power grid or a load device.

[0044] In some embodiments, as Figure 2 As shown, the second end of the power conversion module 132 is connected to the load 15 via the switch module 133. The switch module 133 is used to disconnect or connect the power conversion module 132 and the load 15.

[0045] It should be noted that when the power conversion module 132 is controlled to enter the open-loop control state, the switch module 133 needs to be controlled to disconnect the connection between the power conversion module 132 and the load 15. When the power conversion module 132 does not need to be controlled to enter the open-loop control state, the switch module 133 can be controlled to connect the power conversion module 132 to the load 15.

[0046] See also Figure 3 , Figure 3 1 is a circuit diagram of a photovoltaic energy storage circuit 13 provided in an embodiment of the present application.

[0047] like Figure 3 As shown, the photovoltaic array 14 can be multiple, such as Figure 3 The photovoltaic array PV1 and the photovoltaic array PV2, etc. The boost module 130 includes at least two boost units, such as a first boost unit 1300 and a second boost unit 1301, each of which corresponds to a photovoltaic array. The first boost unit 1300 includes a capacitor C PV1 , inductor L1, diode D1 and switch tube S1; the second boost unit 1301 includes a capacitor C PV2 , inductor L2, diode D2 and switch S2. For the connection relationship between the components in the boost module 130, please refer to Figure 3 , I will not go into details here.

[0048] like Figure 3 As shown, the power conversion module 132 may include a three-phase three-level inverter circuit 1320 and a balanced bridge circuit 1321 , and each phase of the three-level inverter circuit includes a capacitor and an inductor.

[0049] For example, in the three-phase three-level inverter circuit 1320, the first phase three-level inverter circuit includes a switch tube Q 1a , switch tube Q 1b , switch tube Q 1c , switch tube Q 1d 、Inductor L 1a 、Inductor L 2a and capacitor C3; the second phase three-level inverter circuit includes a switch tube Q 2a , switch tube Q 2b , switch tube Q 2c , switch tube Q 2d 、Inductor L 1b 、Inductor L 2b And capacitor C4; the third phase three-level inverter circuit includes a switch tube Q 3a , switch tube Q 3b , switch tube Q 3c , switch tube Q 3d 、Inductor L 1c 、Inductor L2c And capacitor C5. Among them, each switch tube may include but is not limited to a triode, a field effect tube (Metal-Oxide-Semiconductor Field-Effect Transistor, MOS), an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), etc. The three-phase three-level inverter circuit 1320 may also include capacitors C7 and C8. For the connection relationship between the various components in the three-phase three-level inverter circuit 1320, please refer to Figure 3 , I will not go into details here.

[0050] like Figure 3 As shown, the balanced bridge circuit 1321 may include a switch tube Q 4a , switch tube Q 4b And inductor L3. Among them, the connection relationship between the components in the balanced bridge circuit 1321, please refer to Figure 3 , I will not go into details here.

[0051] For example, Figure 3 As shown, the switch module 133 may include a relay S 1a 、Relay S 1b 、Relay S 1c 、Relay S 1n 、Relay S 2a 、Relay S 2b 、Relay S 2c 、Relay S 2n , used to disconnect or connect the power conversion module 132 and the load 15. Of course, the relay in the switch module 133 can also be replaced by a switching device such as a triode, a MOS tube, an IGBT tube and an optical coupler. Figure 3 U_grid, V_grid, W_grid, and N_grid are used to connect to a load 15 (not shown in the figure).

[0052] In some embodiments, a capacitor voltage corresponding to each phase of the three-level inverter circuit may be obtained and detected to obtain a first detection result; and / or an inductor current corresponding to each phase of the three-level inverter circuit may be obtained and detected to obtain a first detection result. If the first detection result is abnormal, it is determined that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0053] Among them, the capacitor voltage refers to the voltage across capacitors C3, C4, and C5; the inductor current refers to the current flowing through the inductor L 1a 、Inductor L 1b and the inductor L 1c It should be noted that when the switch module 133 is disconnected, the inductor L2a 、Inductor L 2b and inductor L 2c No current flows, the inductor L 2a 、Inductor L 2b and inductor L 2c The corresponding inductor currents can be used as the capacitor currents corresponding to the capacitors C3 , C4 and C5 , respectively.

[0054] In some embodiments, as Figure 3 As shown, at least one bus capacitor is provided on the DC bus 131. For example, bus capacitor C1 and bus capacitor C2 are provided on the DC bus 131. After controlling the switching units in the boost module 130 and the switching units in the power conversion module 132 to be turned off, an abnormality detection can be performed based on the input voltage of the photovoltaic array 14 and the capacitor voltage of the bus capacitor to obtain a second detection result. When the second detection result is abnormal, a prompt message is output to indicate an abnormality in the sampling circuit of the photovoltaic energy storage circuit 13.

[0055] It should be noted that the input voltage of the photovoltaic array 14 can charge the bus capacitor C1 and the bus capacitor C2 until the bus voltage of the DC bus 131 reaches the first voltage threshold. bus It refers to the sum of the voltage of the bus capacitor C1 and the voltage of the bus capacitor C2; the first voltage threshold can be set according to the performance parameters of the bus capacitor C1 and the bus capacitor C2.

[0056] It is understood that the photovoltaic energy storage circuit 13 is equipped with a sampling circuit for collecting the capacitor voltage of the bus capacitor. When the boost module 130 and the power conversion module 132 are not operating (i.e., the switch units in the boost module 130 and the switch units in the power conversion module 132 are off), the input voltage of the photovoltaic array 14 should be equal to or nearly equal to the capacitor voltage of the bus capacitor. If the difference between the input voltage and the capacitor voltage of the bus capacitor is large, it indicates that the sampling circuit of the photovoltaic energy storage circuit 13 has an abnormality.

[0057] In some embodiments, as Figure 2 and Figure 3 As shown, the energy storage module 134 is connected to the DC bus 131, and a first detection voltage detected by the energy storage module 134 on the DC bus 131 can be obtained, as well as a second detection voltage detected by the power conversion module 132 on the DC bus 131. An abnormality detection is performed based on the first detection voltage and the second detection voltage to obtain a third detection result. When the third detection result is abnormal, a third prompt information is output to indicate that the sampling circuit of the photovoltaic energy storage circuit 13 is abnormal.

[0058] It should be noted that energy storage module 134 can be a DC-DC converter; both energy storage module 134 and power conversion module 132 are equipped with sampling circuits. Since both energy storage module 134 and power conversion module 132 perform voltage detection on DC bus 131, the first detection voltage detected by energy storage module 134 and the second detection voltage detected by power conversion module 132 should be equal or nearly equal. If the difference between the first detection voltage and the second detection voltage is large, it indicates that there is an abnormality in the sampling circuit of energy storage module 134 or the sampling circuit of power conversion module 132, that is, the sampling circuit of photovoltaic energy storage circuit 13 is abnormal.

[0059] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features of the embodiments can be combined with each other. Figure 4 , Figure 4 This is a schematic flow chart of an anomaly detection method provided in an embodiment of the present application. Figure 4 As shown, the abnormality detection method includes steps S101 to S103.

[0060] Step S101: When the bus voltage of the DC bus is equal to or greater than a first voltage threshold, output a preset control signal to control the power conversion module to enter an open-loop no-load state.

[0061] Exemplarily, when the bus voltage of the DC bus is equal to or greater than a first voltage threshold, a preset control signal is output to control the power conversion module to enter an open-loop no-load state.

[0062] It should be noted that when the photovoltaic energy storage circuit in the energy storage device is activated, the photovoltaic array can charge the bus capacitor on the DC bus through the boost module in the photovoltaic energy storage circuit until the bus voltage of the DC bus is equal to or greater than a first voltage threshold. The first voltage threshold can be set based on the performance parameters of the bus capacitor, and the specific value is not limited here.

[0063] For example, Figure 3 As shown, the photovoltaic array PV1 and / or the photovoltaic array PV2 can charge the bus capacitor C1 and the bus capacitor C2. When the input voltage of the photovoltaic array PV1 and / or the photovoltaic array panel PV2 charges the bus capacitor C1 and the bus capacitor C2, if the bus voltage V bus If the voltage is equal to or greater than the first voltage threshold, a preset control signal is output to control the power conversion module to enter an open-loop no-load state.

[0064] It should be noted that the open-loop no-load state means that the power conversion module is disconnected from the load and only the on / off control of the switching units in the power conversion module is performed. The operation of the power conversion module under the control of the preset control signal is not monitored. The preset control signal can be a high-level signal or a low-level signal and can also include a related duty cycle and frequency.

[0065] In an embodiment of the present application, the power conversion module is controlled to enter an open-loop no-load state by outputting a preset control signal. Subsequently, when the power conversion module is operating in the open-loop no-load state, the capacitor voltage and / or inductor current in the power conversion module can be detected to avoid the sampling circuit in the power conversion module being affected by the load.

[0066] In some embodiments, outputting a preset control signal to control the power conversion module to enter an open-loop no-load state may include: controlling the switch module to disconnect the connection between the power conversion module and the load, and performing open-loop control on the on and off of each switch unit in the power conversion module based on the preset control signal.

[0067] For example, Figure 3 As shown, a shut-off signal can be output to the relay S in the switch module. 1a 、Relay S 1b 、Relay S 1c and relay S 1n , so that the relay S 1a 、Relay S 1b 、Relay S 1c and relay S 1n In the disconnected state, the connection between the power conversion module and the load is disconnected. It can also output a shutdown signal to the relay S in the switch module. 2a 、Relay S 2b 、Relay S 2c and relay S 2n , so that the relay S 2a 、Relay S 2b 、Relay S 2c and relay S 2n The power module is in the disconnected state, thereby disconnecting the connection between the power conversion module and the load.

[0068] For example, the on / off of each phase three-level inverter circuit in the power conversion module can be open-loop controlled based on the preset control signal. For example, the switch tube Q in the first phase three-level inverter circuit can be controlled based on the preset control signal. 1a , switch tube Q 1b , switch tube Q 1c And the switch tube Q 1dFor another example, the switch tube Q in the second phase three-level inverter circuit can be controlled based on the preset control signal. 2a , switch tube Q 2b , switch tube Q 2c And the switch tube Q 2d The on and off of the controller are open-loop controlled.

[0069] In the above embodiment, the power conversion module can enter an open-loop no-load state by controlling the switch module to disconnect the connection between the power conversion module and the load, and performing open-loop control on the on-off of each switch unit in the power conversion module based on a preset control signal.

[0070] Step S102: Detect the capacitor voltage and / or the inductor current in the power conversion module in an open-loop no-load state to obtain a first detection result.

[0071] Please note that, see Figure 3 The power conversion module includes a three-phase, three-level inverter circuit, each phase of which includes a capacitor and an inductor. In embodiments of the present application, the power conversion module may further include a sampling circuit, such as a voltage sampling circuit and a current sampling circuit. The voltage sampling circuit may be used to sample the voltage of the power conversion module, and the current sampling circuit may be used to sample the current of the power conversion module. The specific sampling circuits and sampling methods are not limited herein.

[0072] For example, the capacitor voltage corresponding to the capacitor and the inductor current corresponding to the inductor in each phase of the three-level inverter circuit can be sampled in sequence by a sampling circuit, and then the capacitor voltage corresponding to the capacitor and the inductor current corresponding to the inductor in each phase of the three-level inverter circuit can be detected. Figure 3 As shown, for the first phase three-level inverter circuit, the capacitor voltage of capacitor C3 and the inductor L can be collected. 1a The inductor current, and the capacitor voltage of capacitor C3 and / or inductor L 1a The inductor current is detected to obtain a first detection result.

[0073] It should be noted that detecting the capacitor voltage involves comparing the detected capacitor voltage with a reference voltage collected by the sampling circuit under normal conditions to determine whether the current sampling circuit is abnormal. Detecting the inductor current involves comparing the detected inductor current with a reference current collected by the sampling circuit under normal conditions to determine whether the current sampling circuit is abnormal. The following details how these detections are performed.

[0074] In some embodiments, detecting the capacitor voltage in the power conversion module in an open-loop no-load state to obtain a first detection result may include: obtaining the capacitor voltage corresponding to each phase three-level inverter circuit, detecting the capacitor voltage, and obtaining the first detection result.

[0075] For example, the voltage sampling circuit can be used to sequentially collect the voltage of the capacitor in each phase three-level inverter circuit to obtain the capacitor voltage corresponding to each phase three-level inverter circuit, and the capacitor voltage is detected to obtain the first detection result. Figure 3 As shown, the capacitor voltages corresponding to the capacitors C3, C4 and C5 collected by the voltage sampling circuit can be obtained, and the capacitor voltages corresponding to the capacitors C3, C4 and C5 can be detected to obtain a first detection result.

[0076] Among them, detecting the capacitor voltage to obtain a first detection result may include: determining a first voltage difference between the capacitor voltage and a reference voltage, where the reference voltage is the capacitor voltage of each phase of the three-level inverter circuit when the power conversion module is in a normal state and under the control of a preset control signal; when the absolute value of the first voltage difference is greater than a second voltage threshold, determining that the first detection result is abnormal.

[0077] It should be noted that the power conversion module being in a normal state refers to the sampling circuit in the power conversion module being in a normal state. The reference voltage is the capacitor voltage of each phase of the three-level inverter circuit collected by the sampling circuit when the sampling circuit is in a normal state and the power conversion module is under the control of a preset control signal.

[0078] It can be understood that due to the different duty cycles and frequencies of controlling each switch tube in the power conversion module, the capacitor voltage of each phase three-level inverter circuit may be different. Therefore, the capacitor voltage is obtained when the power conversion module is in an open-loop no-load state and is controlled based on a preset control signal, and the reference voltage is obtained when the power conversion module is in a normal state and is controlled by a preset control signal. Under the same preset control signal, the duty cycle and frequency of the switch tube corresponding to the capacitor voltage and the reference voltage are made the same, thereby making the capacitor voltage and the reference voltage comparable.

[0079] For example, the capacitor voltage can be subtracted from the reference voltage to obtain a first voltage difference. When the absolute value of the first voltage difference is greater than a second voltage threshold, the first detection result is determined to be abnormal. The second voltage threshold can be set based on actual conditions, and the specific value is not limited here.

[0080] In the above embodiment, by determining the first voltage difference between the capacitor voltage and the reference voltage, it can be determined that an abnormality occurs in the voltage sampling circuit in the power conversion module when the absolute value of the first voltage difference is greater than the second voltage threshold.

[0081] In other embodiments, detecting the inductor current in the power conversion module in an open-loop no-load state to obtain a first detection result may include: obtaining the inductor current corresponding to each phase of the three-level inverter circuit, detecting the inductor current, and obtaining the first detection result.

[0082] For example, the current sampling circuit can be used to sequentially collect current from the inductor in each phase of the three-level inverter circuit to obtain the inductor current corresponding to each phase of the three-level inverter circuit, and the inductor current can be detected to obtain the first detection result. Figure 3 As shown, the inductance L can be obtained 1a 、Inductor L 1b and the inductor L 1c The corresponding inductor current and the inductor L 1a 、Inductor L 1b and the inductor L 1c The corresponding inductor current is detected to obtain a first detection result.

[0083] In one embodiment, detecting the inductor current and obtaining a first detection result may include determining a first current difference between the inductor current and a reference current, where the reference current is the inductor current of each phase of the three-level inverter circuit when the power conversion module is in a normal state and under the control of a preset control signal; and determining that the first detection result is abnormal when the absolute value of the first current difference is greater than a preset current threshold. The first current difference may be obtained by subtracting the inductor current from the reference current. The current threshold may be set based on actual conditions, and the specific value is not limited herein.

[0084] In the above embodiment, by determining the first current difference between the inductor current and the reference current, it can be determined that an abnormality occurs in the current sampling circuit in the power conversion module when the absolute value of the first current difference is greater than a preset current threshold.

[0085] In other embodiments, detecting the capacitor voltage and inductor current in the power conversion module in an open-loop no-load state to obtain a first detection result may also include: obtaining the capacitor voltage corresponding to each phase of the three-level inverter circuit, detecting the capacitor voltage, and obtaining the first detection result; obtaining the inductor current corresponding to each phase of the three-level inverter circuit, detecting the inductor current, and obtaining the first detection result.

[0086] It should be noted that in the embodiment of the present application, the voltage detection result obtained by detecting the capacitor voltage and the current detection result obtained by detecting the inductor current can be used together as the first detection result. The specific detection process can be referred to the detailed description of the above embodiment and will not be repeated here.

[0087] In the above embodiment, by detecting the capacitor voltage and / or inductor current in the power conversion module in an open-loop no-load state, the sampling circuit in the photovoltaic energy storage circuit can be prevented from being affected by the load, and whether the sampling circuit is abnormal can be determined in a timely and accurate manner, thereby effectively improving the accuracy of abnormality detection in the photovoltaic energy storage circuit.

[0088] Step S103: When the first detection result is abnormal, output first prompt information, where the first prompt information is used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0089] For example, when the first detection result is abnormal, a first prompt message is output to indicate that the sampling circuit of the photovoltaic energy storage circuit is abnormal. The first prompt message can be output in the form of voice, text, SMS, indicator light, etc.

[0090] For example, when the first detection result is an abnormal capacitor voltage, a first prompt message may be output in text on the display screen of the energy storage device, where the first prompt message may be "abnormal capacitor voltage." For another example, when the first detection result is an abnormal inductor current, a first prompt message may be output in text on the display screen of the energy storage device, where the first prompt message may be "abnormal inductor current."

[0091] By outputting the first prompt information for prompting that the sampling circuit of the photovoltaic energy storage circuit is abnormal when the first detection result is abnormal, the user can be reminded in time that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0092] It should be noted that in the embodiments of the present application, the sampling circuit in the photovoltaic energy storage circuit not only collects the capacitor voltage of each capacitor and the inductor current of each inductor in each phase of the three-level inverter circuit, but also collects the capacitor voltage of the bus capacitor. Therefore, it is also possible to determine whether the sampling circuit is abnormal by performing abnormality detection on the capacitor voltage of the bus capacitor. The following describes in detail the abnormality detection of the capacitor voltage of the bus capacitor.

[0093] See also Figure 5 , Figure 5 It is a schematic flowchart of another anomaly detection method provided in an embodiment of the present application, which may include the following steps S201 to S203.

[0094] Step S201: Control each boost unit in the boost module and each switch unit in the power conversion module to be turned off, so that the input voltage of the photovoltaic array charges the bus capacitor.

[0095] It should be noted that after the PV array is connected to the energy storage device, the PV array outputs operating power to the energy storage device, which completes initialization and enters power-on self-test mode. Power-on self-test mode means that both the boost module and the power conversion module in the PV energy storage circuit are inoperative. Specifically, all boost units in the boost module and all switch units in the power conversion module are turned off.

[0096] For example, a shutdown signal can be sent to each boost unit in the boost module to shut down each boost unit in the boost module; a shutdown signal can be sent to each switch unit in the power conversion module to shut down each switch unit in the power conversion module.

[0097] For example, Figure 3 As shown, a shutdown signal can be sent to the switch tube S1 and the switch tube S2 in the boost module to turn off the switch tube S1 and the switch tube S2. A shutdown signal can also be sent to the switch tube Q in the power conversion module. 1a , switch tube Q 1b , switch tube Q 1c , switch tube Q 1d , switch tube Q 2a , switch tube Q 2b , switch tube Q 2c , switch tube Q 2d , switch tube Q 3a , switch tube Q 3b , switch tube Q 3c , switch tube Q 3d , switch tube Q 4a And the switch tube Q 4b , so that each switch tube is turned off.

[0098] By controlling the shutdown of each boost unit in the boost module and each switch unit in the power conversion module, each boost unit in the boost module and each switch unit in the power conversion module do not consume energy, which can improve the accuracy of subsequent abnormality detection based on the input voltage and the capacitor voltage of the bus capacitor.

[0099] It is understandable that when the boost units in the boost module and the switch units in the power conversion module do not consume power, the input voltage of the photovoltaic array directly charges the bus capacitor, and after the bus capacitor is fully charged, the capacitor voltage across the bus capacitor should be equal to or approximately equal to the input voltage. If the difference between the input voltage and the capacitor voltage of the bus capacitor is large, it indicates that there is an abnormality in the sampling circuit of the photovoltaic energy storage circuit. This allows the voltage difference between the capacitor voltage and the input voltage to be compared, avoiding the voltage loss of the boost module and the power conversion module that makes it impossible to accurately compare the voltage difference between the capacitor voltage and the input voltage.

[0100] Step S202: Perform an abnormality detection based on the input voltage and the capacitor voltage of the bus capacitor to obtain a second detection result.

[0101] For example, a sampling circuit may be used to collect the capacitance voltage of the bus capacitor, and an abnormality detection may be performed based on the input voltage and the capacitance voltage of the bus capacitor to obtain a second detection result. For example, it may be possible to detect whether the absolute value of the voltage difference between the input voltage and the capacitance voltage of the bus capacitor is greater than a certain voltage threshold.

[0102] In some embodiments, performing abnormality detection based on the output voltage and the capacitor voltage of the bus capacitor to obtain a second detection result may include: determining a second voltage difference between the output voltage and the capacitor voltage of the bus capacitor; and determining that the second detection result is abnormal when the absolute value of the second voltage difference is greater than a third voltage threshold.

[0103] For example, the output voltage can be subtracted from the capacitor voltage of the bus capacitor to obtain a second voltage difference. When the absolute value of the second voltage difference is greater than a third voltage threshold, the second detection result is determined to be abnormal. The third voltage threshold can be set based on actual conditions, and the specific value is not limited here.

[0104] In the above embodiment, by determining the second voltage difference between the output voltage and the capacitor voltage of the bus capacitor, it can be determined that an abnormality occurs in the voltage sampling circuit in the power conversion module when the absolute value of the second voltage difference is greater than the third voltage threshold.

[0105] Step S203: When the second detection result is abnormal, output second prompt information, where the second prompt information is used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0106] For example, when the second detection result is abnormal, a second prompt message is output to indicate that the sampling circuit of the photovoltaic energy storage circuit is abnormal. The second prompt message can be output in the form of voice, text, SMS, indicator light, etc. For example, when the second detection result is abnormal capacitor voltage, the second prompt message can be output in text form on the display screen of the energy storage device.

[0107] By outputting the second prompt information for prompting that the sampling circuit of the photovoltaic energy storage circuit is abnormal when the second detection result is abnormal, the user can be reminded in time that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0108] It should be noted that in the embodiments of the present application, the photovoltaic energy storage circuit also includes an energy storage module. Both the energy storage module and the power conversion module are equipped with sampling circuits for sampling the voltage of the bus capacitor. Therefore, it is also possible to detect abnormalities in the sampling circuits in the energy storage module and the sampling circuits in the power conversion module. The following details how to detect abnormalities in the sampling circuits in the energy storage module and the sampling circuits in the power conversion module.

[0109] See also Figure 6 , Figure 6 It is a schematic flowchart of another anomaly detection method provided in an embodiment of the present application, which may include the following steps S301 to S304.

[0110] Step S301: Acquire a first detection voltage of the energy storage module, where the first detection voltage is a bus voltage of the DC bus detected by the energy storage module.

[0111] Exemplarily, the bus voltage of the DC bus detected by the sampling circuit in the energy storage module may be used as the first detection voltage of the energy storage module.

[0112] Step S302: Acquire a second detection voltage of the power conversion module, where the second detection voltage is a bus voltage of the DC bus detected by the power conversion module.

[0113] Exemplarily, the bus voltage of the DC bus detected by the sampling circuit in the power conversion module can be used as the second detection voltage of the power conversion module.

[0114] Step S303: Perform abnormality detection based on the first detection voltage and the second detection voltage to obtain a third detection result.

[0115] It should be noted that since both the energy storage module and the power conversion module detect the DC bus voltage, the first detection voltage detected by the energy storage module and the second detection voltage detected by the power conversion module should be equal or nearly equal. If the difference between the first and second detection voltages is large, it indicates that there is an abnormality in the sampling circuit of the energy storage module or the sampling circuit of the power conversion module, that is, the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0116] Exemplarily, an abnormality detection may be performed based on the first detection voltage and the second detection voltage to obtain a third detection result.

[0117] Among them, performing abnormality detection based on the first detection voltage and the second detection voltage to obtain a third detection result may include: determining a third voltage difference between the first detection voltage and the second detection voltage; when the absolute value of the third voltage difference is greater than a fourth voltage threshold, determining that the third detection result is abnormal.

[0118] For example, the first detection voltage can be subtracted from the second detection voltage to obtain a third voltage difference. When the absolute value of the third voltage difference is greater than a fourth voltage threshold, the third detection result is determined to be abnormal. The fourth voltage threshold can be set based on actual conditions, and the specific value is not limited here.

[0119] In the above embodiment, by using the third voltage difference between the first detection voltage and the second detection voltage, when the absolute value of the third voltage difference is greater than the fourth voltage threshold, it can be determined that an abnormality has occurred in the sampling circuit of the energy storage module or the sampling circuit of the power conversion module, and further, it can be determined that an abnormality has occurred in the voltage sampling circuit in the power conversion module.

[0120] Step S304: When the third detection result is abnormal, output third prompt information, where the third prompt information is used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0121] For example, when the third detection result is abnormal, a third prompt message is output to indicate that the sampling circuit of the photovoltaic energy storage circuit is abnormal. The third prompt message can be output in the form of voice, text, SMS, indicator light, etc.

[0122] For example, when the third detection result is abnormal, the third prompt information can be output in text form on the display screen of the energy storage device.

[0123] By outputting the third prompt information for prompting that the sampling circuit of the photovoltaic energy storage circuit is abnormal when the third detection result is abnormal, the user can be promptly reminded that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0124] An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program. The computer program includes program instructions, and the processor executes the above program instructions to implement any anomaly detection method provided in the embodiment of the present application.

[0125] For example, when the program is loaded by the processor, the following steps may be performed:

[0126] When the bus voltage of the DC bus is equal to or greater than a first voltage threshold, a preset control signal is output to control the power conversion module to enter an open-loop no-load state; the capacitor voltage and / or the inductor current in the power conversion module in the open-loop no-load state are detected to obtain a first detection result; when the first detection result is abnormal, a first prompt information is output, and the first prompt information is used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

[0127] The computer-readable storage medium may be an internal storage unit of the energy storage device described in the aforementioned embodiment, such as a hard disk or memory of the energy storage device. The computer-readable storage medium may also be an external storage device of the energy storage device, such as a plug-in hard disk, a smart memory card (SMC), a secure digital card (SD card), a flash card, etc. equipped on the energy storage device.

[0128] Furthermore, the computer-readable storage medium may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, programs required for at least one function, etc.; the data storage area may store data created according to each program, etc.

[0129] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and such modifications or substitutions should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for detecting anomalies, characterized in that: The method is used to detect abnormalities in a photovoltaic energy storage circuit, wherein the photovoltaic energy storage circuit includes a boost module and a power conversion module, wherein a first end of the boost module is used to connect to a photovoltaic array, a second end of the boost module is used to connect to a first end of the power conversion module via a DC bus, and a second end of the power conversion module is used to connect to a load; the method includes: When the bus voltage of the DC bus is equal to or greater than a first voltage threshold, outputting a preset control signal to control the power conversion module to enter an open-loop no-load state; detecting a capacitor voltage and / or an inductor current in the power conversion module in an open-loop no-load state to obtain a first detection result; When the first detection result is abnormal, outputting first prompt information, wherein the first prompt information is used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal; The power conversion module includes a three-phase three-level inverter circuit, and each phase of the three-level inverter circuit includes a capacitor and an inductor; the capacitor voltage and / or inductor current in the power conversion module in an open-loop no-load state are detected to obtain a first detection result, including: Obtaining a capacitor voltage corresponding to each phase of the three-level inverter circuit, detecting the capacitor voltage to obtain the first detection result; and / or acquiring an inductor current corresponding to each phase of the three-level inverter circuit, detecting the inductor current to obtain a first detection result; The anomaly detection method further includes: determining a first voltage difference between the capacitor voltage and a reference voltage, where the reference voltage is a capacitor voltage of each phase of the three-level inverter circuit when the power conversion module is in a normal state and under the control of the preset control signal; When the absolute value of the first voltage difference is greater than a second voltage threshold, the first detection result is determined to be abnormal.

2. The anomaly detection method according to claim 1, wherein: The photovoltaic energy storage circuit further includes a switch module, and the second end of the power conversion module is connected to the load through the switch module; the output preset control signal controls the power conversion module to enter an open-loop no-load state, including: The switch module is controlled to disconnect the power conversion module from the load, and open-loop control is performed on the on-off of each switch unit in the power conversion module based on the preset control signal.

3. The anomaly detection method according to claim 1, wherein: A bus capacitor is provided on the DC bus, and the method further includes: Controlling each boost unit in the boost module and each switch unit in the power conversion module to turn off, so that the input voltage of the photovoltaic array charges the bus capacitor; Performing abnormality detection based on the input voltage and the capacitor voltage of the bus capacitor to obtain a second detection result; When the second detection result is abnormal, second prompt information is output, where the second prompt information is used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

4. The anomaly detection method according to claim 3, wherein: The performing abnormality detection based on the input voltage and the capacitor voltage of the bus capacitor to obtain a second detection result includes: determining a second voltage difference between the input voltage and a capacitor voltage of the bus capacitor; When the absolute value of the second voltage difference is greater than a third voltage threshold, the second detection result is determined to be abnormal.

5. The anomaly detection method according to claim 1, wherein: The photovoltaic energy storage circuit further includes an energy storage module, and the energy storage module is connected to the DC bus; the method further includes: Acquire a first detection voltage of the energy storage module, where the first detection voltage is a bus voltage of the DC bus detected by the energy storage module; Acquire a second detection voltage of the power conversion module, where the second detection voltage is a bus voltage of the DC bus detected by the power conversion module; performing abnormality detection based on the first detection voltage and the second detection voltage to obtain a third detection result; When the third detection result is abnormal, a third prompt message is output, where the third prompt message is used to prompt that the sampling circuit of the photovoltaic energy storage circuit is abnormal.

6. The anomaly detection method according to claim 5, characterized in that: The performing abnormality detection according to the first detection voltage and the second detection voltage to obtain a third detection result includes: determining a third voltage difference between the first detection voltage and the second detection voltage; When the absolute value of the third voltage difference is greater than a fourth voltage threshold, the third detection result is determined to be abnormal.

7. An energy storage device, characterized in that: The energy storage device includes a memory, a processor and a photovoltaic energy storage circuit; The memory is used to store computer programs; The processor is configured to execute the computer program and implement the anomaly detection method according to any one of claims 1 to 6 when executing the computer program.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor implements the abnormality detection method according to any one of claims 1 to 6.

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