Fault detection system and method of differential operational amplifier and energy storage system

Abstract

The invention discloses a fault detection system and method of a differential operational amplifier and an energy storage system, and the system comprises the differential operational amplifier which comprises a normal phase input end, an inverted input end and an output end; the first voltage sampling circuit is connected with the normal phase input end for sampling and outputting a first voltage; the second voltage sampling circuit is connected with the inverted input end for sampling and outputting a second voltage; the controller is connected with the output end so as to adjust the working state of the converter assembly according to the voltage of the output end, and the controller is further connected with the first voltage sampling circuit and the second voltage sampling circuit; and the controller is used for stopping the operation of the converter assembly when the first voltage is not equal to the second voltage, and is also used for stopping the operation of the converter assembly when the first voltage is equal to the second voltage and the voltage of the output end is abnormal. According to the fault detection system provided by the invention, the detection of the differential operational amplifier can be realized, and the potential safety hazard of the energy storage system is avoided.

Description

Technical Field

[0001] The present application relates to the field of electronic circuit technology, and in particular to a fault detection system, method and energy storage system for a differential operational amplifier. Background Art

[0002] Household photovoltaic storage is a new type of clean energy, and its core equipment is photovoltaic inverter and energy storage converter. Photovoltaic inverter realizes the conversion of DC of photovoltaic panels into AC and connects to the grid. Energy storage converter realizes the conversion of battery voltage DC into AC and connects to the grid, and can also convert grid AC into DC to charge and discharge batteries, realizing two-way conversion of energy.

[0003] Both photovoltaic inverters and energy storage converters require differential operational amplifiers, which are used to sample voltage and current for photovoltaic inverter on-grid and off-grid control or energy storage converter charge and discharge control. Currently, the differential operational amplifiers of photovoltaic inverters and energy storage converters do not monitor the failure of the operational amplifiers themselves. Once the operational amplifiers work abnormally or fail completely, they will directly affect the photovoltaic inverter on-grid and off-grid control or energy storage converter charge and discharge control, causing fault shutdown or device damage. Summary of the invention

[0004] The embodiments of the present application provide a fault detection system, method and energy storage system for a differential operational amplifier, which can realize the detection of the operational amplifier in the differential operational amplifier.

[0005] In a first aspect, an embodiment of the present application provides a fault detection system for a differential operational amplifier, comprising:

[0006] A differential operational amplifier, comprising a non-inverting input terminal, an inverting input terminal and an output terminal;

[0007] A first voltage sampling circuit, connected to the non-inverting input terminal to perform sampling and output a first voltage;

[0008] A second voltage sampling circuit connected to the inverting input terminal to perform sampling and output a second voltage;

[0009] a controller connected to the output end to adjust the working state of the converter component according to the voltage of the output end, and the controller is also connected to the first voltage sampling circuit and the second voltage sampling circuit;

[0010] The controller is used to stop the operation of the converter component when the first voltage and the second voltage are not equal, and is also used to stop the operation of the converter component when the first voltage and the second voltage are equal and the voltage at the output end is abnormal.

[0011] In some embodiments, the fault detection system further includes a sampling circuit, wherein the sampling circuit is provided with two voltage output terminals, and the two voltage output terminals are respectively connected to the non-phase input terminal and the inverting input terminal.

[0012] In some embodiments, the fault detection system further includes a switching device and a reference voltage source, wherein the reference voltage source is connected to the non-inverting input terminal and the inverting input terminal through the switching device.

[0013] In some embodiments, the switching device is a double-pole double-throw relay, one switch of the relay is connected between the positive electrode of the reference voltage source and the non-phase input terminal, and the other switch is connected between the negative electrode of the reference voltage source and the inverting input terminal.

[0014] In some embodiments, the first voltage sampling circuit includes a first voltage divider circuit and a first operational amplifier, and the voltage at the voltage dividing point of the first voltage divider circuit is processed by the first operational amplifier to output the first voltage; the second voltage sampling circuit includes a second voltage divider circuit and a second operational amplifier, and the voltage at the voltage dividing point of the second voltage divider circuit is processed by the second operational amplifier to output the second voltage.

[0015] In a second aspect, an embodiment of the present application provides a fault detection method of a fault detection system, which is applied to the fault detection system of the first aspect, comprising:

[0016] When the first voltage is not equal to the second voltage, stopping the operation of the converter component;

[0017] When the first voltage is equal to the second voltage and the voltage at the output end is abnormal, the converter component stops working.

[0018] In some embodiments, when the first voltage is equal to the second voltage and the voltage at the output end is abnormal, stopping the operation of the converter component includes:

[0019] When the first voltage is equal to the second voltage, determining a difference between the voltage at the output terminal and a voltage standard value;

[0020] When the difference is greater than a preset threshold, the operation of the current conversion component is stopped.

[0021] In some embodiments, the fault detection system further includes a switching device and a reference voltage source, wherein the reference voltage source is connected to the non-inverting input terminal and the inverting input terminal through the switching device; and the fault detection method further includes:

[0022] Before the current conversion component is started, controlling the switching device to connect the reference voltage source to the non-phase input terminal and the inverting input terminal;

[0023] Acquire the first voltage, the second voltage, and the voltage of the output end;

[0024] When the first voltage and the second voltage are not equal, the current conversion component is not started;

[0025] When the first voltage is equal to the second voltage and the voltage at the output end is abnormal, the converter component is not started.

[0026] In some embodiments, stopping the operation of the converter assembly includes:

[0027] Stop outputting the pulse width modulation signal to the power switch device of the converter component.

[0028] In a third aspect, an embodiment of the present application provides an energy storage system, comprising the fault detection system of the first aspect, or executing the fault detection method of the second aspect.

[0029] The fault detection system, method and energy storage system of the differential operational amplifier of the embodiment of the present application have at least the following beneficial effects: the voltages of the non-phase input terminal and the inverting input terminal of the differential operational amplifier are collected by the first voltage sampling circuit and the second voltage sampling circuit to obtain the first voltage and the second voltage. When the first voltage and the second voltage are not equal, it indicates that the differential operational amplifier itself has failed, and the operation of the conversion component is directly stopped. When the first voltage and the second voltage are equal but the voltage at the output terminal is abnormal, it indicates that the amplification ratio of the differential operational amplifier is out of balance, and the operation of the conversion component is also directly stopped. In the above manner, it is possible to detect whether the differential operational amplifier has an abnormality, and when an abnormality occurs, the conversion component can be stopped in time to avoid safety hazards in the energy storage system.

[0030] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a circuit diagram of a fault detection system for a differential operational amplifier provided in an embodiment of the present application;

[0032] Figure 2 is a circuit diagram of a Hall current sampling circuit provided in an embodiment of the present application;

[0033] Figure 3 is a circuit diagram of a resistor current sampling circuit provided in an embodiment of the present application;

[0034] Figure 4 It is a flowchart of a fault detection method provided in an embodiment of the present application;

[0035] Figure 5 It is a flow chart of a method for detecting abnormal output voltage provided by an embodiment of the present application;

[0036] Figure 6 It is a flowchart of a pre-startup self-check method provided in an embodiment of the present application;

[0037] Figure 7 It is a flow chart of a method for stopping the working of a converter component provided in an embodiment of the present application;

[0038] Figure 8 It is a module structure diagram of a fault detection system for a differential operational amplifier provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. In addition, the characteristics, operations or features described in the specification can be combined in any appropriate manner to form various implementation methods. At the same time, the steps or actions in the method description can also be replaced or adjusted in order in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the accompanying drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0040] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0041] The serial numbers of the components in this document, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0042] Under the background of "carbon peak" and "carbon neutrality", household photovoltaic storage, as a new type of clean energy, has become the main development direction. The core equipment used in household photovoltaic storage is photovoltaic inverter and energy storage converter. Photovoltaic inverter realizes the conversion of DC of photovoltaic panels into AC and connects to the grid. Energy storage converter realizes the conversion of battery voltage DC into AC and connects to the grid. It can also convert AC of the grid into DC to charge and discharge the battery, realizing two-way conversion of energy.

[0043] Both photovoltaic inverters and energy storage converters use a large number of op amp differential circuits to sample voltage and current for photovoltaic inverter on-grid and off-grid control or energy storage converter charge and discharge control. However, the current op amp differential circuits of photovoltaic inverters and energy storage converters do not monitor the failure of the op amp itself. Once the op amp fails, the voltage sampling signal and current sampling signal used for on-grid and off-grid control or charge and discharge control will have a great deviation, which will lead to control disorder. In the worst case, the power switch tube of the photovoltaic inverter and energy storage converter will explode due to overcurrent or overvoltage, which poses a certain safety risk.

[0044] Based on this, the embodiments of the present application provide a fault detection system, method and energy storage system for a differential operational amplifier, which can detect the operational amplifier in the differential operational amplifier and stop the current conversion component in time when an abnormality occurs.

[0045] First of all, a photovoltaic inverter is an inverter that can convert the variable DC voltage generated by photovoltaic (PV) solar panels into alternating current (AC) at the mains frequency, which can be fed back to the commercial power transmission system or used for off-grid power grids; while the energy storage inverter can control the charging and discharging process of the battery, perform AC / DC conversion, and directly supply power to AC loads in the absence of a power grid.

[0046] The following is a description of a fault detection system, method and energy storage system of a differential operational amplifier in conjunction with the accompanying drawings:

[0047] Reference Figure 1 As shown, Figure 1It is a circuit diagram of a fault detection system of a differential operational amplifier provided in an embodiment of the present application, including: a differential operational amplifier, including a non-phase input terminal, an inverting input terminal and an output terminal; a first voltage sampling circuit, connected to the non-phase input terminal for sampling and outputting a first voltage VP12; a second voltage sampling circuit, connected to the inverting input terminal for sampling and outputting a second voltage VN12; a controller, connected to the output terminal to adjust the working state of the converter component according to the voltage V-P2N2 at the output terminal, and the controller is also connected to the first voltage sampling circuit and the second voltage sampling circuit; the controller is used to stop the operation of the converter component when the first voltage VP12 and the second voltage VN12 are not equal, and is also used to stop the operation of the converter component when the first voltage VP12 and the second voltage VN12 are equal and the voltage V-P2N2 at the output terminal is abnormal.

[0048] Reference Figure 8 As shown, Figure 8 It is a module structure diagram of a fault detection system for a differential operational amplifier provided in an embodiment of the present application.

[0049] It can be understood that the two input signals VP1 and VN1 are respectively connected to the two input terminals of the differential operational amplifier, one input signal VP1 is connected to the non-inverting input terminal (positive pole), and the other input signal VN1 is connected to the inverting input terminal (negative pole). The differential operational amplifier adds resistors in the feedback path to control the amplification factor and gain, where R1=R2, R3=R4. When the input signal is applied to the differential amplifier circuit, the operational amplifier will amplify the difference between the two input signals VP1 and VN1, that is, the differential part of the input signal. The amplified differential signal will output the voltage V-P2N2 through the output port of the differential operational amplifier.

[0050] The differential operational amplifier receives the voltage VP1 of the non-inverting input terminal and the voltage VN1 of the inverting input terminal, amplifies the difference between the two input terminal voltages with a fixed gain and outputs it to the output terminal. In addition, the first voltage sampling circuit is connected to the non-inverting input terminal, the controller controls the first voltage sampling circuit to sample the voltage VP1 of the non-inverting input terminal, and outputs the sampling result as the first voltage VP12. At the same time, the second voltage sampling circuit is connected to the inverting input terminal, the controller controls the second voltage sampling circuit to sample the voltage VN1 of the inverting input terminal, and outputs the sampling result as the second voltage VN12. The controller controls the second voltage sampling circuit to sample the voltage VN1 of the inverting input terminal according to the first voltage sampling circuit. The sampling results of a voltage VP12 and a second voltage VN12 are compared. When the first voltage VP12 and the second voltage VN12 are not equal, that is, there is a difference between the positive input terminal and the negative input terminal, the controller will stop the operation of the converter component to avoid abnormal operation of the system; when the first voltage VP12 and the second voltage VN12 are equal, that is, there is no difference between the positive input terminal and the negative input terminal, the controller will further detect whether the voltage V-P2N2 at the output terminal is abnormal. If the voltage V-P2N2 at the output terminal is abnormal, the controller will also stop the operation of the converter component to prevent possible faults.

[0051] In some embodiments, the fault detection system of the differential operational amplifier further includes a sampling circuit, and the sampling circuit is provided with two voltage output terminals, and the two voltage output terminals are respectively connected to the non-phase input terminal and the inverting input terminal.

[0052] Reference Figure 2 As shown, Figure 2 This is a circuit diagram of a Hall current sampling circuit provided in an embodiment of the present application. The current is input into the Hall current sampling circuit through the current sensor pin, and the input current is converted into a corresponding voltage signal through the Hall element. In addition, the two voltage output terminals are respectively connected to the non-phase input terminal and the inverting input terminal, and the voltage signals VP1 and VN1 are input into the differential operational amplifier.

[0053] Reference Figure 3 As shown, Figure 3 This is a circuit diagram of a resistor current sampling circuit provided in an embodiment of the present application. The current is input into the resistor current sampling circuit through the current sensor pin. Different currents pass through the sampling resistor to generate different voltage signals according to V=I*R. The two voltage output terminals are respectively connected to the positive input terminal and the negative input terminal. The voltage signals VP1 and VN1 are input into the differential operational amplifier.

[0054] In some embodiments, the fault detection system of the differential operational amplifier further includes a switching device and a reference voltage source, wherein the reference voltage source is connected to the non-inverting input terminal and the inverting input terminal through the switching device.

[0055] In some embodiments, the switching device is a double-pole double-throw relay, one switch of the relay is connected between the positive electrode of the reference voltage source and the non-inverting input terminal, and the other switch is connected between the negative electrode of the reference voltage source and the inverting input terminal.

[0056] It should be noted that the switching device uses a double-pole double-throw relay, one switch is connected between the positive pole of the reference voltage source and the positive input terminal, and the other switch is connected between the negative pole of the reference voltage source and the inverting input terminal. When the change in the input quantity reaches the specified requirements, the relay plays the role of automatic adjustment, switching circuit, etc. When the relay is in a normal working state, one of the switches connects the positive pole of the reference voltage source to the positive input terminal, and the other switch connects the negative pole of the reference voltage source to the inverting input terminal. In this way, under normal circumstances, the input voltage difference of the differential operational amplifier will be amplified with the voltage difference generated by the reference voltage source, thereby outputting the corresponding amplified voltage signal V-P2N2. When the fault detection system detects an abnormality, it switches and disconnects the circuit to avoid overcurrent and overvoltage stress damage to the power switch device.

[0057] It should be noted that the reference voltage source is connected to the non-inverting input terminal and the inverting input terminal through a switching device to provide a known stable reference voltage.

[0058] It should be noted that, through the switching of the relay and the reference voltage source, the fault detection system of the differential operational amplifier can stop the operation of the differential operational amplifier immediately when an abnormality is detected.

[0059] In some embodiments, the first voltage sampling circuit includes a first voltage divider circuit and a first operational amplifier, and the voltage at the voltage dividing point of the first voltage divider circuit is processed by the first operational amplifier to output the first voltage VP12; the second voltage sampling circuit includes a second voltage divider circuit and a second operational amplifier, and the voltage at the voltage dividing point of the second voltage divider circuit is processed by the second operational amplifier to output the second voltage VN12.

[0060] It should be noted that the first voltage sampling circuit includes a first voltage divider circuit for dividing the input voltage VP1. The first voltage divider circuit is composed of a resistor network, which divides the input voltage VP1 to a desired range. There is a voltage signal VP11 at the voltage dividing point of the voltage divider circuit. The voltage signal VP11 at the voltage dividing point is processed by the first operational amplifier, which can amplify the input voltage signal VP1 and output the processed first voltage signal VP12, which usually has the ability to adjust gain and bias.

[0061] On the other hand, the second voltage sampling circuit includes a second voltage divider circuit for dividing the input voltage VN1. The second voltage divider circuit is composed of a resistor network, which divides the input voltage VN1 to a desired range. There is a voltage signal VN11 at the voltage dividing point of the voltage divider circuit. The voltage signal VN11 at the voltage dividing point is processed by a second operational amplifier, which can amplify the input voltage signal VN1 and output a processed second voltage signal VN12, which usually has the ability to adjust gain and bias.

[0062] Reference Figure 4 As shown, Figure 4 A fault detection method of a fault detection system provided in an embodiment of the present application is applied to a fault detection system of a differential operational amplifier. The fault detection system includes a differential operational amplifier, a first voltage sampling circuit, a second voltage sampling circuit and a controller. The detection method may include but is not limited to the following steps:

[0063] Step S410, when the first voltage and the second voltage are not equal, stopping the operation of the converter component;

[0064] It should be noted that the voltage signal VP1 is input to the first voltage sampling circuit, which includes a first voltage divider circuit and a first operational amplifier. The first voltage divider circuit divides the voltage signal VP1 and outputs the divided voltage signal VP11 to the voltage dividing point. The voltage signal VP11 at the voltage dividing point is amplified by the first operational amplifier to output the first voltage signal VP12.

[0065] On the other hand, the voltage signal VN1 is input to the second voltage sampling circuit, which includes a second voltage divider circuit and a second operational amplifier. The second voltage divider circuit divides the voltage signal VN1 and outputs the divided voltage signal VN11 to the voltage dividing point. The voltage signal VN11 at the voltage dividing point is amplified by the second operational amplifier to output the second voltage signal VN12.

[0066] It should be noted that when the controller determines that the first voltage signal VP12 output by the first voltage sampling circuit and the second voltage signal VN12 output by the second voltage sampling circuit are not equal, the operation of the photovoltaic inverter and the energy storage converter is stopped, and the input of the voltage signals VP1 and VN1 to the positive input terminal and the negative input terminal of the differential operational amplifier is stopped. At the same time, an error message and an alarm are issued to the user to remind the user that the differential operational amplifier is in a completely failed state.

[0067] Step S420: When the first voltage and the second voltage are equal and the voltage at the output end is abnormal, the operation of the converter component is stopped.

[0068] It should be noted that when the controller determines that the first voltage signal VP12 output by the first voltage sampling circuit and the second voltage signal VN12 output by the second voltage sampling circuit are equal, the output voltage V-P2N2 of the differential operational amplifier is detected. When the controller determines that the output voltage V-P2N2 is abnormal, the operation of the photovoltaic inverter and the energy storage converter is stopped, the input of the voltage signals VP1 and VN1 to the positive input and negative input of the differential operational amplifier is stopped, and an error is reported to the user.

[0069] Reference Figure 5 As shown, Figure 5 A fault detection method for detecting abnormal output voltage provided by an embodiment of the present application is applied to a fault detection system of a differential operational amplifier, the fault detection system comprising a differential operational amplifier, a first voltage sampling circuit, a second voltage sampling circuit and a controller; the detection method may include but is not limited to the following steps:

[0070] Step S510, when the first voltage and the second voltage are equal, determining the difference between the voltage at the output terminal and the voltage standard value;

[0071] It should be noted that the voltage standard value is the voltage value obtained by amplifying the input reference voltage value according to the standard ratio of the differential operational amplifier.

[0072] It should be understood that the controller detects the voltage value V-P2N2 at the output terminal and determines the difference from the voltage standard value.

[0073] Step S520: When the difference is greater than a preset threshold, the operation of the converter component is stopped.

[0074] It should be noted that when the difference is greater than the preset threshold, the photovoltaic inverter and the energy storage converter are stopped, and the voltage signals VP1 and VN1 at the positive and negative input terminals of the differential operational amplifier are stopped. At the same time, an error message and an alarm are given to the user to remind the user that the differential operational amplifier is out of proportion or the resistor has failed, resulting in a huge deviation in accuracy.

[0075] It should be noted that when the difference is greater than the preset threshold, the error is too large and will directly affect the normal control of the photovoltaic inverter and the energy storage converter, causing control imbalance and overcurrent or overvoltage damage to the power semiconductor.

[0076] Reference Figure 6 As shown, Figure 6A pre-startup self-test method provided by an embodiment of the present application is applied to a fault detection system of a differential operational amplifier, the fault detection system comprising a differential operational amplifier, a first voltage sampling circuit, a second voltage sampling circuit and a controller, the fault detection system further comprising a switching device and a reference voltage source, the reference voltage source being connected to a non-inverting input terminal and an inverting input terminal through the switching device; the self-test method may include but is not limited to the following steps:

[0077] Step S610, before the converter component is started, controlling the switching device to connect the reference voltage source to the non-phase input terminal and the inverting input terminal;

[0078] It should be noted that the reference voltage source is connected to the non-inverting input terminal and the inverting input terminal through a switching device, and is used to provide a known stable reference voltage for self-test.

[0079] Step S620, obtaining a first voltage, a second voltage, and a voltage at an output terminal;

[0080] It should be noted that, during the self-test process, a first voltage VP12 is obtained, and the voltage signal VP1 is input into a first voltage sampling circuit. The first voltage sampling circuit includes a first voltage divider circuit and a first operational amplifier. The first voltage divider circuit divides the voltage signal VP1 and outputs the divided voltage signal VP11 to a voltage dividing point. The voltage signal VP11 at the voltage dividing point is amplified by the first operational amplifier to output a first voltage signal VP12.

[0081] On the other hand, during the self-test process, a first voltage VN12 is obtained, and a voltage signal VN1 is input into a second voltage sampling circuit. The second voltage sampling circuit includes a second voltage divider circuit and a second operational amplifier. The second voltage divider circuit divides the voltage signal VN1 and outputs the divided voltage signal VN11 to a voltage dividing point. The voltage signal VN11 at the voltage dividing point is amplified by the second operational amplifier to output a second voltage signal VN12.

[0082] It should be noted that the voltage signals VP1 and VN1 are input to the non-inverting input terminal and the inverting input terminal of the differential operational amplifier. The differential operational amplifier adds a resistor in the feedback path to control the amplification factor and gain. The differential operational amplifier amplifies the difference between the two self-test voltage signals VP1 and VN1, that is, the differential part of the input signal. The amplified differential signal will be output through the output port of the differential operational amplifier, thereby obtaining the voltage signal V-P2N2 at the output terminal.

[0083] Step S630, when the first voltage and the second voltage are not equal, the converter component is not started;

[0084] It should be noted that when the first voltage VP12 and the second voltage VN12 obtained by the pre-startup self-test method are not equal, the photovoltaic inverter and the energy storage converter will not be started to avoid over-current and over-voltage stress damage to the power switching devices, which may cause safety failures in the product. At the same time, errors and alarms are reported to the user to remind the user that the differential operational amplifier is in a completely failed state.

[0085] Step S640: When the first voltage and the second voltage are equal and the voltage at the output end is abnormal, the converter component is not started.

[0086] It should be noted that when the first voltage VP12 and the second voltage VN12 obtained by the pre-startup self-test method are equal, the difference between the output voltage V-P2N2 and the voltage standard value is determined. When the difference is greater than the preset threshold, the controller determines that the output voltage V-P2N2 is abnormal, and does not start the photovoltaic inverter and the energy storage converter to prevent faulty operation and over-power modulation, which may cause overcurrent or overvoltage damage to the power semiconductor. At the same time, errors and alarms are reported to the user to remind the user that the differential operational amplifier is out of proportion or the resistor has failed, resulting in a large deviation in accuracy.

[0087] Reference Figure 7 As shown, Figure 7 The present invention is a flowchart of a method for stopping the operation of a converter component provided by an embodiment of the present invention, which is applied to a fault detection system of a differential operational amplifier. The fault detection system includes a differential operational amplifier, a first voltage sampling circuit, a second voltage sampling circuit and a controller. The stopping method may include but is not limited to the following steps:

[0088] Step S710, detecting a signal for stopping the operation of the converter component;

[0089] It should be noted that the controller detects a signal to stop the operation of the conversion component in two situations. In the first situation, when the first voltage signal VP12 output by the first voltage sampling circuit and the second voltage signal VN12 output by the second voltage sampling circuit are not equal, the differential transport amplifier is in a completely failed state, and the controller detects a signal to stop the operation of the conversion component; in the second situation, when the first voltage signal VP12 output by the first voltage sampling circuit and the second voltage signal VN12 output by the second voltage sampling circuit are equal, the output terminal voltage V-P2N2 is detected, and the difference between the output terminal voltage V-P2N2 and the voltage standard value is determined. When the difference is greater than the preset threshold, the controller determines that the output terminal voltage V-P2N2 is abnormal, and the differential transport amplifier is out of proportion or the resistor fails, and the controller detects a signal to stop the operation of the conversion component.

[0090] Step S720, stop outputting the pulse width modulation signal to the power switch device of the converter assembly.

[0091] It should be noted that when the controller detects a signal to stop the operation of the conversion component, it turns off the PWM drive signal of the power switching device, stops the operation of the photovoltaic inverter and the energy storage converter, and avoids over-current and over-voltage stress damage to the power switching device, which may cause safety failures in the product.

[0092] An embodiment of the present application further provides an energy storage system, which includes the fault detection system described above, or executes the fault detection method described above.

[0093] The household storage system is a product directly facing users. As the core components of the household storage system, the safety of photovoltaic inverters and energy storage converters is of vital importance. The voltage and current signal sampling in photovoltaic inverters and energy storage converters uses a large number of signal conditioning differential operational amplifier circuits, so the failure monitoring of differential operational amplifiers is particularly important. The scheme of the present invention can monitor the failure of differential operational amplifiers and predict the failure of differential operational amplifiers in advance. Once the differential operational amplifier fails, the power switch device is turned off in time to stop the operation of photovoltaic inverters and energy storage converters to avoid the occurrence of safety hazards.

[0094] The present application collects the voltages of the non-phase input terminal and the inverting input terminal of the differential operational amplifier through the first voltage sampling circuit and the second voltage sampling circuit to obtain the first voltage and the second voltage. When the first voltage and the second voltage are not equal, it indicates that the differential operational amplifier itself has failed, and the operation of the conversion component is directly stopped. When the first voltage and the second voltage are equal but the voltage at the output terminal is abnormal, it indicates that the amplification ratio of the differential operational amplifier is out of balance, and the operation of the conversion component is also directly stopped. In the above manner, it is possible to detect whether the differential operational amplifier has an abnormality, and when an abnormality occurs, the operation of the conversion component can be stopped in time to avoid safety hazards in the energy storage system.

[0095] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed method above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0096] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0097] In several embodiments provided in the present application, it should be understood that the disclosed systems, apparatuses and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of apparatuses or units, which can be electrical, mechanical or other forms. The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment.

[0098] It should also be understood that the various implementations provided in the embodiments of the present application can be combined arbitrarily to achieve different technical effects.

[0099] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present application. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A fault detection system for a differential operational amplifier, characterized in that: include: A differential operational amplifier, comprising a non-inverting input terminal, an inverting input terminal and an output terminal; A first voltage sampling circuit, connected to the non-inverting input terminal to perform sampling and output a first voltage; A second voltage sampling circuit connected to the inverting input terminal to perform sampling and output a second voltage; a controller connected to the output end to adjust the working state of the converter component according to the voltage of the output end, and the controller is also connected to the first voltage sampling circuit and the second voltage sampling circuit; The controller is used to stop the operation of the converter component when the first voltage and the second voltage are not equal, and is also used to stop the operation of the converter component when the first voltage and the second voltage are equal and the voltage at the output end is abnormal.

2. The fault detection system according to claim 1, characterized in that: It also includes a sampling circuit, which is provided with two voltage output terminals, and the two voltage output terminals are respectively connected to the positive phase input terminal and the negative phase input terminal.

3. The fault detection system according to claim 2, characterized in that: It also includes a switching device and a reference voltage source, wherein the reference voltage source is connected to the non-inverting input terminal and the inverting input terminal through the switching device.

4. The fault detection system according to claim 3, characterized in that: The switching device is a double-pole double-throw relay, one switch of the relay is connected between the positive electrode of the reference voltage source and the non-phase input terminal, and the other switch is connected between the negative electrode of the reference voltage source and the inverting input terminal.

5. The fault detection system according to claim 1, characterized in that: The first voltage sampling circuit includes a first voltage divider circuit and a first operational amplifier, and the voltage at the voltage dividing point of the first voltage divider circuit is processed by the first operational amplifier to output the first voltage; the second voltage sampling circuit includes a second voltage divider circuit and a second operational amplifier, and the voltage at the voltage dividing point of the second voltage divider circuit is processed by the second operational amplifier to output the second voltage.

6. A fault detection method for a fault detection system, characterized in that: Applied to the fault detection system according to any one of claims 1 to 5, the fault detection method comprises: When the first voltage is not equal to the second voltage, stopping the operation of the converter component; When the first voltage is equal to the second voltage and the voltage at the output end is abnormal, the converter component stops working.

7. The fault detection method according to claim 6, characterized in that: When the first voltage is equal to the second voltage and the voltage at the output end is abnormal, stopping the operation of the converter component includes: When the first voltage is equal to the second voltage, determining a difference between the voltage at the output terminal and a voltage standard value; When the difference is greater than a preset threshold, the operation of the current conversion component is stopped.

8. The fault detection method according to claim 6, characterized in that: The fault detection system further comprises a switching device and a reference voltage source, wherein the reference voltage source is connected to the non-inverting input terminal and the inverting input terminal through the switching device; The fault detection method further comprises: Before the current conversion component is started, controlling the switching device to connect the reference voltage source to the non-phase input terminal and the inverting input terminal; Acquire the first voltage, the second voltage, and the voltage of the output end; When the first voltage and the second voltage are not equal, the current conversion component is not started; When the first voltage is equal to the second voltage and the voltage at the output end is abnormal, the converter component is not started.

9. The fault detection method according to claim 8, characterized in that: The stopping of the operation of the converter assembly includes: Stop outputting the pulse width modulation signal to the power switch device of the converter component.

10. An energy storage system, characterized in that: It comprises a fault detection system as claimed in any one of claims 1 to 5, or executes a fault detection method as claimed in any one of claims 6 to 9.

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