Detection circuit, detection method, device and readable storage medium

Abstract

The application provides a detection circuit, a detection method, a device and a readable storage medium. The detection circuit comprises a resistance component, a switch component and a control device. The switch component is connected in series between an output end and a ground end of a direct current bus; and the control device is connected with the first relay component and the switch component. The control device is used for: controlling the switch component to switch from an off state to an on state when the first relay component is in the off state; acquiring a first voltage difference value of the switch component in the off state and a second voltage difference value of the switch component in the on state, wherein the first voltage difference value and the second voltage difference value are both voltage difference values between a first end and a second end of the first relay component; and determining a fault state of the first relay component according to the first voltage difference value and the second voltage difference value.

Description

Technical Field

[0001] This invention belongs to the field of energy storage converter technology, and more specifically, relates to a detection circuit, detection method, device, and readable storage medium. Background Technology

[0002] To improve the safety of residential energy storage converters, electrical isolation between the converter's output and the grid is required via relays. This means installing relays between the grid's live and neutral wires and the converter's output. Before connecting the energy storage converter to the grid, the relays must be checked for faults.

[0003] In related technologies, fault detection of relays is carried out through circuit design, which involves complex hardware setup and high detection costs. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems existing in the prior art or related technologies.

[0005] Therefore, a detection circuit is proposed as a first aspect of the present invention.

[0006] A second aspect of the present invention provides a detection method.

[0007] A third aspect of the present invention provides a detection device.

[0008] A fourth aspect of the present invention provides a detection component.

[0009] A fifth aspect of the present invention provides a readable storage medium.

[0010] The sixth aspect of the present invention provides an energy storage system.

[0011] In view of this, according to a first aspect of the present invention, a detection circuit is provided for detecting the fault state of a first relay assembly between the neutral line of the DC bus of an energy storage converter and the neutral line of a three-phase power supply. The detection circuit includes a resistor assembly, a switch assembly, and a control device. The switch assembly and the resistor assembly are connected in series between the output terminal and the ground terminal of the DC bus; the control device is connected to both the first relay assembly and the switch assembly.

[0012] The control device is used to: control a switch to switch from an open state to an on state when the first relay assembly is in an open state; acquire a first voltage difference value when the switch is in an open state and a second voltage difference value when the switch is in an on state, wherein both the first voltage difference value and the second voltage difference value are voltage differences between the first terminal and the second terminal of the first relay assembly; and determine the fault state of the first relay assembly based on the first voltage difference value and the second voltage difference value.

[0013] This invention proposes a detection circuit for an energy storage converter. Electrical isolation is achieved between the neutral line of the energy storage converter's DC bus and the neutral line of the three-phase power supply via a first relay assembly. When the energy storage converter operates in grid-connected mode, the first relay assembly controlling the connection between the neutral line of the energy storage converter's DC bus and the neutral line of the three-phase power supply is disconnected, ensuring that the energy storage converter has no electrical connection to the power grid on the neutral line and avoiding potential safety hazards.

[0014] The first relay assembly includes at least two relays. When the first relay assembly is connected to the grid, all relays in the first relay assembly are kept in the open state to ensure that the two ends of the first relay assembly are not in the conducting state. Even if some of the relays in the first relay assembly fail, the electrical isolation between the neutral line of the DC bus of the energy storage converter and the neutral line of the three-phase power supply can still be guaranteed, which has a better isolation effect than a single relay.

[0015] The detection circuit includes a resistor assembly, a switch, and a control device. The resistor assembly and the switch are connected in series, and the series-connected resistor assembly and switch are connected between the output terminal of the DC bus and the ground terminal.

[0016] The control device is connected to the switching element, and the control device can control the on / off state of the switching element. The control device is also connected to the first relay assembly, and the control device can control the on / off state of the first relay assembly.

[0017] When the control device controls the first relay assembly to be in the off state, it needs to control each relay in the first relay assembly to be in the off state to ensure that the first relay assembly is in a completely off state. When the control device controls the first relay assembly to be in the on state, it needs to control each relay in the first relay assembly to be in the on state.

[0018] The control device can switch the on / off state between the output terminal and the ground terminal of the DC bus by switching the on / off state of the switching element. During the process of the control device controlling the detection of whether the first relay assembly has a sticking fault, by controlling the switching element to switch the on / off state and obtaining the voltage difference between the two ends of the first relay assembly before and after the switching state is switched, the device can accurately determine whether the first relay assembly has a fault based on the voltage difference before and after the on / off state switch.

[0019] Before the energy storage converter is connected to the grid, the control device is used to detect whether there is a sticking fault in the first relay assembly. The specific detection process for the first relay assembly is as follows:

[0020] During the initial testing phase, both the control switch and the first relay assembly are in the open state, and the first voltage difference across the first relay assembly is detected. This first voltage difference allows for a preliminary assessment of whether the first relay is faulty. If the first voltage difference is small, it indicates that the first relay assembly may be in a conducting state. Due to the design of the energy storage converter's grounding system, the voltage across the first relay assembly may be close to 0. Therefore, the control switch is switched to the conducting state, and the second voltage value across the first relay assembly is detected. After the switch is turned on, the resistor assembly is connected between the output of the DC bus and the grounding system, thereby changing the voltage value at the end of the first relay assembly closest to the DC bus neutral line. If the second voltage difference across the first relay assembly is still small, then a fault in the first relay assembly can be determined.

[0021] It should be noted that since the first relay assembly includes at least two relays, and the first relay assembly is in the open state when all of its relays are in the open state, it can be determined that there is at least one relay with a sticking fault in the first relay assembly.

[0022] This invention connects a resistor and a switch in series between the output and ground terminals of the DC bus of an energy storage converter. Before the switch is turned on, a first voltage difference is detected across a first relay assembly; after the switch is turned off, a second voltage difference is detected. Based on these first and second voltage differences, the presence of a sticking fault in the first relay assembly can be accurately determined. By switching the on / off state of the switch, the connection of the resistor between the DC bus output and ground terminals can be controlled, thereby adjusting the voltage value of the first relay assembly near the DC bus and avoiding false detections of a sticking fault in the first relay assembly.

[0023] The detection circuit in this invention includes only a resistor component and a switch component, and works with control logic to accurately detect whether there is a sticking fault in the first relay component. Compared with related technologies that use complex circuit designs, it has the advantage of low hardware cost, thus ensuring detection accuracy while reducing hardware costs.

[0024] In addition, the detection circuit in the above-described technical solution provided by the present invention may also have the following additional technical features:

[0025] In the above technical solution, the first relay assembly includes: a first relay and a second relay, the first relay and the second relay are connected in series, one end of the first relay is connected to the neutral line of the DC bus, and one end of the second relay is connected to the neutral line of the three-phase power supply.

[0026] The first relay assembly being in the off state includes: the first relay being in the off state and the second relay being in the on state; or the second relay being in the off state and the first relay being in the on state.

[0027] In this technical solution, the first relay assembly includes two relays, namely a first relay and a second relay. The first relay and the second relay are connected in series. The first terminal of the first relay serves as the first terminal of the first relay assembly and is connected to the neutral line of the DC neutral line. The second terminal of the second relay serves as the second terminal of the first relay assembly and is connected to the neutral line of the three-phase power supply. The second terminal of the first relay is connected to the first terminal of the second relay.

[0028] The first relay assembly being in the off state includes any of the following: the first relay is in the off state and the second relay is in the on state; the first relay is in the on state and the second relay is in the off state; or both the first relay and the second relay are in the off state.

[0029] Since the first relay and the second relay in the first relay assembly are connected in series, if either the first relay or the second relay is in an open state, then the first relay assembly is in an open state.

[0030] It should be noted that, in the process of detecting whether the first relay assembly is faulty, by controlling either the first relay or the second relay to be in an open state, it is possible to detect whether the first relay or the second relay in the open state is stuck.

[0031] In this scheme, by setting a first relay and a second relay connected in series in the first relay assembly, it is possible to ensure that the DC bus and the three-phase power supply are electrically isolated when the energy storage converter is operating in grid-connected mode. Compared with the scheme of setting only a single relay between the DC bus and the three-phase power supply, it has higher isolation stability.

[0032] In any of the above technical solutions, the control device determines the fault state of the first relay assembly based on the first voltage difference and the second voltage difference, specifically for:

[0033] Based on the fact that both the first voltage difference and the second voltage difference are less than a preset threshold, it is determined that the target relay in the first relay assembly is in a fault state. The target relay is the relay in the first relay and the second relay that is in the open state.

[0034] In this technical solution, the first voltage difference is the voltage difference detected between the two ends of the first relay assembly when both the switch and the first relay assembly are in the off state. The second voltage difference is the voltage difference detected between the two ends of the first relay assembly when the switch is in the on state and the first relay assembly is in the off state.

[0035] Due to the design of the grounding system (PE) in the energy storage converter system, there is a possibility of misjudgment if the first relay component is faulty based solely on the first voltage difference or the second voltage difference. However, by switching the on / off state of the switching components and adjusting whether the resistor component is connected between the negative terminal of the DC bus and the grounding system, the possibility of misjudgment can be effectively avoided.

[0036] In some possible implementations, when the first relay is controlled to be in an open state and the second relay is controlled to be in an on state, a fault can be detected in the first relay that is controlled to be open, based on the detected first voltage difference and second voltage difference. If both the first voltage difference and the second voltage difference are less than a preset threshold, it is determined that the first relay is in a sticking fault state.

[0037] In some possible implementations, when the second relay is controlled to be in an open state and the first relay is in an on state, a fault can be detected in the second relay by measuring the detected first voltage difference and second voltage difference. If both the first voltage difference and the second voltage difference are less than a preset threshold, the second relay is determined to be in a sticking fault state.

[0038] In some possible implementations, if both the first and second relays are controlled to be in an open state, and both the first voltage difference and the second voltage difference are less than a preset threshold, it is determined that one of the first and second relays is in a state of adhesion failure.

[0039] This solution controls one relay in the first relay assembly to be disconnected while the other relay remains on. Based on the first voltage difference and the second voltage difference, it can accurately detect whether the disconnected relay is in a faulty state, thus achieving the effect of precise fault location of the first relay assembly.

[0040] In any of the above technical solutions, a second relay assembly is provided between the three-phase input terminal of the energy storage converter and the three-phase power supply; the control device is connected to the second relay assembly;

[0041] Before the control switch is switched from the open state to the on state while the first relay assembly is in the open state, the control device is also used to: control the second relay assembly to be in the open state.

[0042] In this technical solution, the second relay assembly is used to control the on / off state between the three-phase input terminal of the energy storage converter and the three-phase power supply.

[0043] The second relay assembly includes three sets of relays, with at least two relays in each set. The first terminals of the three sets of relays are respectively connected to the three-phase input terminals of the energy storage converter, and the second terminals of the three sets of relays are all connected to the three-phase power supply.

[0044] During the process of detecting whether the first relay assembly is faulty through the detection circuit, it is necessary to ensure that the energy storage converter is not in a grid-connected state and the second relay assembly is in an open state, that is, the three-phase power supply and the energy storage converter are disconnected. This improves the accuracy of the detection and avoids the fault caused by connecting the energy storage converter to the three-phase power supply before determining whether the first relay is faulty.

[0045] In any of the above technical solutions, the detection circuit further includes a capacitive component. The capacitive component is disposed between the three-phase input terminals of the energy storage converter and the first relay assembly.

[0046] In this technical solution, a capacitive component for filtering is set between the three-phase input terminal of the energy storage converter and the first relay assembly, which improves the stability of the grid-connected operation of the energy storage converter.

[0047] The capacitive component includes a first capacitor, a second capacitor, and a third capacitor.

[0048] In any of the above technical solutions, the detection circuit further includes a first detection element and a second detection element.

[0049] The first detection element is disposed at the first end of the first relay assembly and is used to collect the voltage value at the first end of the first relay assembly; the second detection element is disposed at the second end of the first relay assembly and is used to collect the voltage value at the second end of the first relay assembly.

[0050] In this technical solution, the sampling end of the first detection element is connected to the first end of the first relay assembly, and the first detection element can detect the voltage value at the first end of the first relay assembly. The sampling end of the second detection element is connected to the second end of the first relay assembly, and the second detection element can detect the voltage value at the second end of the first relay assembly.

[0051] Both the first and second detection elements are connected to the control device. After the first and second detection elements acquire the voltage values ​​of the first and second terminals of the first relay assembly, they transmit these voltage values ​​to the control device. The control device can calculate the difference between the voltage values ​​of the first and second terminals of the first relay assembly to obtain a first voltage difference or a second voltage difference.

[0052] For example, the first detection element, the second detection element, and the control device can be integrated into a single configuration.

[0053] This solution, by setting a first detection element and a second detection element at the first and second ends of the first detection component respectively, can accurately detect the voltage values ​​at the first and second ends of the first relay component, thereby ensuring the accuracy of the calculated first voltage difference and second voltage difference.

[0054] According to a second aspect of the present invention, a detection method is provided for use in the detection circuit of the first aspect described above. The detection method includes:

[0055] When the first relay assembly is in the off state, the control switch switches from the off state to the on state;

[0056] The first voltage difference value when the switching element is in the off state and the second voltage difference value when the switching element is in the on state are obtained. Both the first voltage difference value and the second voltage difference value are the voltage difference between the first terminal and the second terminal of the first relay assembly.

[0057] The fault state of the first relay assembly is determined based on the first voltage difference and the second voltage difference.

[0058] In this technical solution, during the initial detection phase, both the control switch and the first relay assembly are in the open state, and the first voltage difference across the first relay assembly is detected. Based on this first voltage difference, a preliminary judgment can be made as to whether the first relay is faulty. If the first voltage difference is small, it is determined that the first relay assembly may be in a conducting state. Due to the design of the energy storage converter's grounding system, the voltage values ​​across the first relay assembly may be close to 0. Therefore, the control switch is switched to the conducting state at this time, and the second voltage value across the first relay assembly is detected. After the switch is turned on, the resistor assembly is connected between the output terminal of the DC bus and the grounding system, thereby changing the voltage value of the end of the first relay assembly closest to the DC bus neutral line. If the second voltage difference across the first relay assembly is still small at this point, it can be determined that the first relay assembly is faulty.

[0059] It should be noted that since the first relay assembly includes at least two relays, and the first relay assembly is in the open state when all of its relays are in the open state, it can be determined that there is at least one relay with a sticking fault in the first relay assembly.

[0060] This invention connects a resistor and a switch in series between the output and ground terminals of the DC bus of an energy storage converter. Before the switch is turned on, a first voltage difference is detected across a first relay assembly; after the switch is turned off, a second voltage difference is detected. Based on these first and second voltage differences, the presence of a sticking fault in the first relay assembly can be accurately determined. By switching the on / off state of the switch, the connection of the resistor between the DC bus output and ground terminals can be controlled, thereby adjusting the voltage value of the first relay assembly near the DC bus and avoiding false detections of a sticking fault in the first relay assembly.

[0061] The detection circuit in this invention includes only a resistor component and a switch component, and works with control logic to accurately detect whether there is a sticking fault in the first relay component. Compared with related technologies that use complex circuit designs, it has the advantage of low hardware cost, thus ensuring detection accuracy while reducing hardware costs.

[0062] In the above technical solution, the first relay assembly includes a first relay and a second relay;

[0063] The first relay assembly being in the off state includes: the first relay being in the off state; and / or the second relay being in the off state.

[0064] The first relay assembly being in the off state includes: the first relay being in the off state and the second relay being in the on state; or the second relay being in the off state and the first relay being in the on state.

[0065] In this technical solution, the first relay assembly includes two relays, namely a first relay and a second relay. The first relay and the second relay are connected in series. The first terminal of the first relay serves as the first terminal of the first relay assembly and is connected to the neutral line of the DC neutral line. The second terminal of the second relay serves as the second terminal of the first relay assembly and is connected to the neutral line of the three-phase power supply. The second terminal of the first relay is connected to the first terminal of the second relay.

[0066] The first relay assembly being in the off state includes any of the following: the first relay is in the off state and the second relay is in the on state; the first relay is in the on state and the second relay is in the off state; or both the first relay and the second relay are in the off state.

[0067] In this scheme, by setting a first relay and a second relay connected in series in the first relay assembly, it is possible to ensure that the DC bus and the three-phase power supply are electrically isolated when the energy storage converter is operating in grid-connected mode. Compared with the scheme of setting only a single relay between the DC bus and the three-phase power supply, it has higher isolation stability.

[0068] In any of the above technical solutions, determining the fault state of the first relay assembly based on the first voltage difference and the second voltage difference includes:

[0069] Based on the fact that both the first voltage difference and the second voltage difference are less than a preset threshold, it is determined that the target relay in the first relay assembly is in a fault state. The target relay is the relay in the first relay and the second relay that is in the open state.

[0070] In this technical solution, the first voltage difference is the voltage difference detected between the two ends of the first relay assembly when both the switch and the first relay assembly are in the off state. The second voltage difference is the voltage difference detected between the two ends of the first relay assembly when the switch is in the on state and the first relay assembly is in the off state.

[0071] Due to the design of the grounding system (PE) in the energy storage converter system, there is a possibility of misjudgment if the first relay component is faulty based solely on the first voltage difference or the second voltage difference. However, by switching the on / off state of the switching components and adjusting whether the resistor component is connected between the negative terminal of the DC bus and the grounding system, the possibility of misjudgment can be effectively avoided.

[0072] This solution controls one relay in the first relay assembly to be disconnected while the other relay remains on. Based on the first voltage difference and the second voltage difference, it can accurately detect whether the disconnected relay is in a faulty state, thus achieving the effect of precise fault location of the first relay assembly.

[0073] In any of the above technical solutions, a second relay assembly is provided between the three-phase input terminal of the energy storage converter and the three-phase power supply;

[0074] Before the control switch is switched from the open state to the on state while the first relay assembly is in the open state, the method further includes: controlling the second relay assembly to be in the open state.

[0075] In this technical solution, the second relay assembly is used to control the on / off state between the three-phase input terminal of the energy storage converter and the three-phase power supply.

[0076] The second relay assembly includes three sets of relays, with at least two relays in each set. The first terminals of the three sets of relays are connected to the three-phase input terminals of the energy storage converter, and the second terminals of the three sets of relays are all connected to the three-phase power supply. The three sets of relays are used to control the on / off state between the three-phase input terminals of the energy storage converter and the three-phase power supply.

[0077] During the process of detecting whether the first relay assembly is faulty through the detection circuit, it is necessary to ensure that the energy storage converter is not in a grid-connected state and the second relay assembly is in an open state, that is, the three-phase power supply and the energy storage converter are disconnected. This improves the accuracy of the detection and avoids the fault caused by connecting the energy storage converter to the three-phase power supply before determining whether the first relay is faulty.

[0078] In any of the above technical solutions, obtaining the first voltage difference value when the switching element is in the off state and the second voltage difference value when the switching element is in the on state includes:

[0079] When the switch is in the off state, a first voltage value at the first terminal of the first relay assembly and a second voltage value at the second terminal of the first relay assembly are acquired; a first voltage difference is determined based on the first voltage value and the second voltage value; when the switch is in the on state, a first voltage value and a third voltage value at the first terminal of the first relay assembly and a fourth voltage value at the second terminal of the first relay assembly are acquired; a second voltage difference is determined based on the third voltage value and the fourth voltage value.

[0080] In this technical solution, the detection circuit also includes a first detection element and a second detection element.

[0081] The first detection element is disposed at the first end of the first relay assembly and is used to collect the voltage value at the first end of the first relay assembly; the second detection element is disposed at the second end of the first relay assembly and is used to collect the voltage value at the second end of the first relay assembly.

[0082] In this technical solution, the sampling end of the first detection element is connected to the first end of the first relay assembly, and the first detection element can detect the voltage value at the first end of the first relay assembly. The sampling end of the second detection element is connected to the second end of the first relay assembly, and the second detection element can detect the voltage value at the second end of the first relay assembly.

[0083] Both the first and second detection elements are connected to the control device. After the first and second detection elements acquire the voltage values ​​of the first and second terminals of the first relay assembly, they transmit these voltage values ​​to the control device. The control device can calculate the difference between the voltage values ​​of the first and second terminals of the first relay assembly to obtain a first voltage difference or a second voltage difference.

[0084] This solution, by setting a first detection element and a second detection element at the first and second ends of the first detection component respectively, can accurately detect the voltage values ​​at the first and second ends of the first relay component, thereby ensuring the accuracy of the calculated first voltage difference and second voltage difference.

[0085] According to a third aspect of the present invention, a detection device is provided for the detection circuit in the first aspect described above, the detection device comprising:

[0086] The control module is used to control the switching element to switch from the off state to the on state when the first relay assembly is in the off state;

[0087] The acquisition module is used to acquire a first voltage difference value when the switching element is in the off state and a second voltage difference value when the switching element is in the on state. Both the first voltage difference value and the second voltage difference value are voltage differences between the first terminal and the second terminal of the first relay assembly.

[0088] The determination module is used to determine the fault state of the first relay assembly based on the first voltage difference and the second voltage difference.

[0089] This invention connects a resistor and a switch in series between the output and ground terminals of the DC bus of an energy storage converter. Before the switch is turned on, a first voltage difference is detected across a first relay assembly; after the switch is turned off, a second voltage difference is detected. Based on these first and second voltage differences, the presence of a sticking fault in the first relay assembly can be accurately determined. By switching the on / off state of the switch, the connection of the resistor between the DC bus output and ground terminals can be controlled, thereby adjusting the voltage value of the first relay assembly near the DC bus and avoiding false detections of a sticking fault in the first relay assembly.

[0090] The detection circuit in this invention includes only a resistor component and a switch component, and works with control logic to accurately detect whether there is a sticking fault in the first relay component. Compared with related technologies that use complex circuit designs, it has the advantage of low hardware cost, thus ensuring detection accuracy while reducing hardware costs.

[0091] According to a fourth aspect of the present invention, a detection component is provided, comprising: a memory storing a program or instructions; and a processor executing the program or instructions stored in the memory to implement the steps of the detection method as described in any of the technical solutions of the second aspect, thus possessing all the beneficial technical effects of the detection method in any of the technical solutions of the second aspect, which will not be elaborated further here.

[0092] According to a fifth aspect of the present invention, a readable storage medium is provided, on which a program or instructions are stored, which, when executed by a processor, implement the steps of the detection method as described in any of the technical solutions of the second aspect above. Therefore, it possesses all the beneficial technical effects of the detection method in any of the technical solutions of the second aspect above, and will not be elaborated further here.

[0093] According to a sixth aspect of the present invention, an energy storage system is provided, comprising: a detection device as defined in the third aspect above, and / or a detection component as defined in the fourth aspect above, and / or a readable storage medium as defined in the fifth aspect above, thus having all the beneficial technical effects of the detection device as defined in the third aspect above, and / or the detection device in the fourth aspect above, and / or the readable storage medium as defined in the fifth aspect above, which will not be elaborated further here.

[0094] Additional aspects and advantages of the invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0095] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0096] Figure 1 A circuit diagram of a detection circuit provided in one embodiment of the present invention is shown;

[0097] Figure 2 A structural block diagram of a detection circuit provided in one embodiment of the present invention is shown;

[0098] Figure 3 One of the schematic flowcharts of a detection method provided in one embodiment of the present invention is shown;

[0099] Figure 4 A second schematic flowchart of a detection method provided in one embodiment of the present invention is shown;

[0100] Figure 5 A structural block diagram of a detection device provided in one embodiment of the present invention is shown;

[0101] Figure 6 A structural block diagram of a detection component provided in one embodiment of the present invention is shown;

[0102] Figure 7 A structural block diagram of an energy storage system provided in one embodiment of the present invention is shown.

[0103] in, Figure 1 and Figure 2 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0104] 100 Detection circuit, 110 Energy storage converter, 112 Neutral line, 120 First relay assembly, S2 First relay, S3 Second relay, R1 Resistor assembly, S1 Switch, 130 Control device, 140 Second relay assembly, 150 Capacitive assembly, C1 First capacitor, C2 Second capacitor, C3 Third capacitor, V1 First detection element, V2 Second detection element, 200 Three-phase power supply. Detailed Implementation

[0105] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0106] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0107] The following reference Figures 1 to 7 The present invention describes detection circuits, detection methods, apparatuses, energy storage systems, and readable storage media according to some embodiments thereof.

[0108] In one embodiment according to this application, such as Figure 1 and Figure 2 As shown, a detection circuit 100 is proposed for detecting the fault state of the first relay assembly 120 between the neutral line 112 of the DC bus of the energy storage converter 110 and the neutral line of the three-phase power supply 200. The detection circuit 100 includes a resistor assembly R1, a switch S1, and a control device 130. The switch S1 and the resistor assembly R1 are connected in series between the output terminal and the ground terminal of the DC bus; the control device 130 is connected to the first relay assembly 120 and the switch S1 respectively.

[0109] The control device 130 is configured to: control the switch S1 to switch from the open state to the on state when the first relay assembly 120 is in the open state; acquire a first voltage difference value when the switch S1 is in the open state and a second voltage difference value when the switch S1 is in the on state, wherein the first voltage difference value and the second voltage difference value are both voltage differences between the first terminal and the second terminal of the first relay assembly 120; and determine the fault state of the first relay assembly 120 based on the first voltage difference value and the second voltage difference value.

[0110] This embodiment proposes a detection circuit 100 for an energy storage converter 110. Electrical isolation is achieved between the neutral line 112 of the DC bus of the energy storage converter 110 and the neutral line of the three-phase power supply 200 via a first relay assembly 120. When the energy storage converter 110 operates in grid-connected mode, the first relay assembly 120 is disconnected between the neutral line 112 of the DC bus of the energy storage converter 110 and the neutral line of the three-phase power supply 200, ensuring that the energy storage converter 110 has no electrical connection to the grid on the neutral line, thus avoiding safety hazards.

[0111] The first relay assembly 120 includes at least two relays. When the first relay assembly 120 is connected to the grid, all relays in the first relay assembly 120 are kept in the open state to ensure that the two ends of the first relay assembly 120 are not in the conducting state. Even if some of the relays in the first relay assembly 120 fail, the electrical isolation between the neutral line 112 of the DC bus of the energy storage converter 110 and the neutral line of the three-phase power supply 200 can still be guaranteed, which has a better isolation effect than a single relay.

[0112] The detection circuit 100 includes a resistor assembly R1, a switch S1, and a control device 130. The resistor assembly R1 and the switch S1 are connected in series, and the series-connected resistor assembly R1 and switch S1 are connected between the output terminal and the ground terminal of the DC bus.

[0113] The resistor assembly R1 includes at least one resistor. In the case where the resistor assembly R1 includes multiple resistors, the multiple resistors are connected in series with each other.

[0114] For example, the first end of resistor component R1 is connected to the output end of DC bus, the second end of resistor component R1 is connected to the first end of switch component S1, and the second end of switch component S1 is grounded.

[0115] For example, the first terminal of the switch S1 is connected to the output terminal of the DC bus, the second terminal of the switch S1 is connected to the first terminal of the resistor assembly R1, and the second terminal of the resistor assembly R1 is grounded.

[0116] The control device 130 is connected to the switch S1, and the control device 130 can control the on / off state of the switch S1. The control device 130 is also connected to the first relay assembly 120, and the control device 130 can control the on / off state of the first relay assembly 120.

[0117] When the control device 130 controls the first relay assembly 120 to be in the off state, it is necessary to control each relay in the first relay assembly 120 to be in the off state to ensure that the first relay assembly 120 is in the completely off state.

[0118] The control device 130 can switch the on / off state between the output terminal and the ground terminal of the DC bus by switching the on / off state of the switching element S1. During the process of the control device 130 controlling the detection of whether the first relay assembly 120 has a sticking fault, by controlling the switching element S1 to switch the on / off state and obtaining the voltage difference across the first relay assembly 120 before and after the switching state is switched, the control device 130 can accurately determine whether the first relay assembly 120 has a fault based on the voltage difference before and after the on / off state switch.

[0119] Before the energy storage converter 110 is connected to the grid, the control device 130 detects whether the first relay assembly 120 has a sticking fault. The specific detection process for the first relay assembly 120 is as follows:

[0120] During the initial detection phase, both control switch S1 and the first relay assembly 120 are in the open state, and the first voltage difference across the first relay assembly 120 is detected. Based on the first voltage difference, a preliminary judgment can be made as to whether the first relay S2 is faulty. If the first voltage difference is small, it is determined that the first relay assembly 120 may be in the closed state. Due to the design of the grounding system of the energy storage converter 110, the voltage value across the first relay assembly 120 may be close to 0. Therefore, control switch S1 is switched to the closed state at this time, and the second voltage value across the first relay assembly 120 is detected. After switch S1 is turned on, resistor R1 is connected between the output terminal of the DC bus and the grounding system, thereby changing the voltage value of the end of the first relay assembly 120 closest to the DC bus neutral line 112. If the second voltage difference across the first relay assembly 120 is still small at this time, it can be determined that the first relay assembly 120 is faulty.

[0121] It should be noted that since the first relay assembly 120 includes at least two relays, and the first relay assembly 120 is in the off state when all of its relays are in the off state, it can be determined that there is at least one relay with a sticking fault in the first relay assembly 120.

[0122] In this embodiment, a resistor assembly R1 and a switch assembly S1 are connected in series between the output terminal and the ground terminal of the DC bus of the energy storage converter 110. Before the switch assembly S1 is turned on, a first voltage difference is detected across the first relay assembly 120, and after the switch assembly S1 is turned on, a second voltage difference is detected across the first relay assembly 120. Based on the first and second voltage differences, it is possible to accurately determine whether the first relay assembly 120 has a sticking fault. By switching the on / off state of the switch assembly S1, it is possible to control whether the resistor assembly R1 is connected between the output terminal and the ground terminal of the DC bus, thereby adjusting the voltage value of the first relay assembly 120 near the DC bus and avoiding false detections of a sticking fault in the first relay assembly 120.

[0123] The detection circuit 100 in this embodiment only includes a resistor component R1 and a switch component S1, and works with control logic to accurately detect whether there is a sticking fault in the first relay component 120. Compared with related technologies that use complex circuit designs, it has the advantage of low hardware cost, thus ensuring detection accuracy while reducing hardware cost.

[0124] In addition, the detection circuit 100 in the above embodiments provided in this embodiment may also have the following additional technical features:

[0125] like Figure 1 and Figure 2 As shown, in the above embodiment, the first relay assembly 120 includes: a first relay S2 and a second relay S3, the first relay S2 and the second relay S3 are connected in series, one end of the first relay S2 is connected to the neutral line 112 of the DC bus, and one end of the second relay S3 is connected to the neutral line of the three-phase power supply 200.

[0126] The first relay assembly 120 being in the off state includes: the first relay S2 being in the off state and the second relay S3 being in the on state; or the second relay S3 being in the off state and the first relay S2 being in the on state.

[0127] In this embodiment, the first relay assembly 120 includes two relays, namely a first relay S2 and a second relay S3. The first relay S2 and the second relay S3 are connected in series. The first terminal of the first relay S2 serves as the first terminal of the first relay assembly 120 and is connected to the neutral line 112 of the DC neutral line. The second terminal of the second relay S3 serves as the second terminal of the first relay assembly 120 and is connected to the neutral line of the three-phase power supply 200. The second terminal of the first relay S2 is connected to the first terminal of the second relay S3.

[0128] The first relay assembly 120 being in the off state includes any of the following: the first relay S2 is in the off state and the second relay S3 is in the on state; the first relay S2 is in the on state and the second relay S3 is in the off state; or both the first relay S2 and the second relay S3 are in the off state.

[0129] Since the first relay S2 and the second relay S3 in the first relay assembly 120 are connected in series, if there is a relay in the first relay S2 and the second relay S3 that is in the open state, then the first relay assembly 120 is in the open state.

[0130] It should be noted that, in the process of detecting whether the first relay assembly 120 is faulty, by controlling either the first relay S2 or the second relay S3 to be in the open state, it is possible to detect whether the first relay S2 or the second relay S3 in the open state is stuck.

[0131] In this embodiment, by setting a first relay S2 and a second relay S3 in series in the first relay assembly 120, it is possible to ensure that the DC bus of the energy storage converter 110 is electrically isolated from the three-phase power supply 200 when the grid-connected state is operating. Compared with the scheme of setting only a single relay between the DC bus and the three-phase power supply 200, it has higher isolation stability.

[0132] like Figure 1 and Figure 2 As shown, in any of the above embodiments, the control device 130 determines the fault state of the first relay assembly 120 based on the first voltage difference and the second voltage difference, specifically for:

[0133] Based on the fact that both the first voltage difference and the second voltage difference are less than a preset threshold, it is determined that the target relay in the first relay assembly 120 is in a fault state. The target relay is the relay in the first relay S2 and the second relay S3 that is in the open state.

[0134] In this embodiment, the first voltage difference is the voltage difference detected between the two ends of the first relay assembly 120 when both the switch S1 and the first relay assembly 120 are in the off state. The second voltage difference is the voltage difference detected between the two ends of the first relay assembly 120 when the switch S1 is in the on state and the first relay assembly 120 is in the off state.

[0135] Due to the design of the grounding system (PE) in the energy storage converter 110 system, there is a possibility of misjudgment if the first relay assembly 120 is faulty based solely on the first voltage difference or the second voltage difference. However, by switching the on / off state of the switch S1 and adjusting whether the resistor assembly R1 is connected between the negative terminal of the DC bus and the grounding system, the possibility of misjudgment can be effectively avoided.

[0136] In some possible implementations, when the first relay S2 is controlled to be in an open state and the second relay S3 is controlled to be in an on state, a fault can be detected in the first relay S2 by measuring the detected first voltage difference and second voltage difference. If both the first voltage difference and the second voltage difference are less than a preset threshold, it is determined that the first relay S2 is in a sticking fault state.

[0137] In some possible implementations, when the second relay S3 is controlled to be in an open state and the first relay S2 is in an on state, a fault can be detected in the second relay S3 by measuring the detected first voltage difference and second voltage difference. If both the first voltage difference and the second voltage difference are less than a preset threshold, the second relay S3 is determined to be in a sticking fault state.

[0138] In some possible implementations, if both the first relay S2 and the second relay S3 are in the off state, and both the first voltage difference and the second voltage difference are less than a preset threshold, it is determined that one of the first relay S2 and the second relay S3 is in a state of adhesion failure.

[0139] This embodiment controls one relay in the first relay assembly 120 to be disconnected while the other relay remains on. Based on the first voltage difference and the second voltage difference, it can accurately detect whether the relay in the disconnected state is in a faulty state, thus achieving the effect of accurately locating the fault in the first relay assembly 120.

[0140] like Figure 1 and Figure 2 As shown, in any of the above embodiments, a second relay assembly 140 is provided between the three-phase input terminal of the energy storage converter 110 and the three-phase power supply 200; the control device 130 is connected to the second relay assembly 140.

[0141] Before the control switch S1 switches from the off state to the on state while the first relay assembly 120 is in the off state, the control device 130 is also used to: control the second relay assembly 140 to be in the off state.

[0142] In this embodiment, the second relay assembly 140 is used to control the on / off state between the three-phase input terminal of the energy storage converter 110 and the three-phase power supply 200.

[0143] The second relay assembly 140 includes three sets of relays, with at least two relays in each set. The first terminals of the three sets of relays are respectively connected to the three-phase input terminals of the energy storage converter 110, and the second terminals of the three sets of relays are all connected to the three-phase power supply 200.

[0144] like Figure 1 As shown, the three sets of relays include relay S for phase A. A1 and relay S A2 The relay S in phase B B1 and relay S B2 C-phase relay S C1 and relay S C2 Series-connected relay S A1 and relay S A2 It can effectively provide electrical isolation between phase A of the three-phase power supply 200 and the input terminal of phase A of the energy storage converter 110. The relay S is connected in series. B1 and relay S B2 It can effectively provide electrical isolation between phase B of the three-phase power supply 200 and the phase B input terminal of the energy storage converter 110. The relay S is connected in series. C1 and relay S C2 This system effectively isolates the C-phase of the three-phase power supply 200 from the C-phase input terminal of the energy storage converter 110. By using two relays connected in series in each relay group, this embodiment effectively avoids electrical isolation failure caused by the failure of one relay, thus improving the operational stability of the energy storage converter 110.

[0145] During the process of detecting whether the first relay assembly 120 has a fault through the detection circuit 100, it is necessary to ensure that the energy storage converter 110 is not in the grid-connected state and the second relay assembly 140 is in the disconnected state, that is, the three-phase power supply 200 and the energy storage converter 110 are disconnected, which improves the accuracy of detection and avoids the fault caused by connecting the energy storage converter 110 to the three-phase power supply 200 before determining whether the first relay S2 has a fault.

[0146] like Figure 1 and Figure 2 As shown, in any of the above embodiments, the detection circuit 100 further includes a capacitive component 150. The capacitive component 150 is disposed between the three-phase input terminal of the energy storage converter 110 and the first relay component 120.

[0147] In this embodiment, a capacitive component 150 for filtering is provided between the three-phase input terminal of the energy storage converter 110 and the neutral line of the three-phase power supply 200, which improves the stability of the grid-connected operation of the energy storage converter 110.

[0148] The capacitive component 150 includes a first capacitor C1, a second capacitor C2, and a third capacitor C3.

[0149] like Figure 1 As shown, the first terminal of the first capacitor C1 is connected between phase A of the three-phase power supply 200 and the first relay assembly 120, the second capacitor C2 is connected between phase B of the three-phase power supply 200 and the first relay assembly 120, and the third capacitor C3 is connected between phase C of the three-phase power supply 200 and the first relay assembly 120.

[0150] In any of the above embodiments, the detection circuit 100 further includes a first detection element V1 and a second detection element V2.

[0151] The first detection element V1 is disposed at the first end of the first relay assembly 120 and is used to collect the voltage value at the first end of the first relay assembly 120; the second detection element V2 is disposed at the second end of the first relay assembly 120 and is used to collect the voltage value at the second end of the first relay assembly 120.

[0152] In this embodiment, the sampling terminal of the first detection element V1 is connected to the first terminal of the first relay assembly 120, and the first detection element V1 can detect the voltage value of the first terminal of the first relay assembly 120. The sampling terminal of the second detection element V2 is connected to the second terminal of the first relay assembly 120, and the second detection element V2 can detect the voltage value of the second terminal of the first relay assembly 120.

[0153] Both the first detection element V1 and the second detection element V2 are connected to the control device 130. After the first detection element V1 and the second detection element V2 acquire the voltage values ​​of the first terminal and the second terminal of the first relay assembly 120, they transmit the acquired voltage values ​​of the first terminal and the second terminal of the first relay assembly 120 to the control device 130. The control device 130 can perform difference calculation based on the voltage values ​​of the first terminal and the second terminal of the first relay assembly 120 to obtain a first voltage difference or a second voltage difference.

[0154] For example, the first detection element V1, the second detection element V2, and the control device 130 can be integrated.

[0155] In this embodiment, by setting a first detection element V1 and a second detection element V2 at the first and second ends of the first detection component respectively, the voltage values ​​at the first and second ends of the first relay component 120 can be accurately detected, thereby ensuring the accuracy of the calculated first voltage difference and second voltage difference.

[0156] In one embodiment according to this application, such as Figure 3 As shown, a detection method is proposed for use in the detection circuit of the first aspect described above. The detection method includes:

[0157] Step 302: When the first relay assembly is in the off state, the control switch is switched from the off state to the on state;

[0158] Step 304: Obtain the first voltage difference value when the switching element is in the off state and the second voltage difference value when the switching element is in the on state. The first voltage difference value and the second voltage difference value are both voltage differences between the first terminal and the second terminal of the first relay assembly.

[0159] Step 306: Determine the fault status of the first relay assembly based on the first voltage difference and the second voltage difference.

[0160] In this embodiment, during the initial detection phase, both the control switch and the first relay assembly are in the off state, and the first voltage difference across the first relay assembly is detected. Based on this first voltage difference, a preliminary judgment can be made as to whether the first relay is faulty. If the first voltage difference is small, it is determined that the first relay assembly may be in a conducting state. Due to the design of the energy storage converter's grounding system, the voltage values ​​across the first relay assembly may be close to 0. Therefore, the control switch is switched to the conducting state, and the second voltage value across the first relay assembly is detected. After the switch is turned on, the resistor assembly is connected between the output terminal of the DC bus and the grounding system, thereby changing the voltage value of the end of the first relay assembly closest to the DC bus neutral line. If the second voltage difference across the first relay assembly is still small, it can be determined that the first relay assembly is faulty.

[0161] It should be noted that since the first relay assembly includes at least two relays, and the first relay assembly is in the open state when all of its relays are in the open state, it can be determined that there is at least one relay with a sticking fault in the first relay assembly.

[0162] This embodiment connects a resistor and a switch in series between the output and ground terminals of the DC bus of the energy storage converter. Before the switch is turned on, a first voltage difference is detected across the first relay assembly; after the switch is turned off, a second voltage difference is detected. Based on these first and second voltage differences, it is possible to accurately determine whether the first relay assembly has a sticking fault. By switching the on / off state of the switch, it is possible to control whether the resistor is connected between the output and ground terminals of the DC bus, thereby adjusting the voltage value of the first relay assembly near the DC bus and avoiding false detections of a sticking fault in the first relay assembly.

[0163] The detection circuit in this embodiment only includes a resistor component and a switch component, and works with control logic to accurately detect whether there is a sticking fault in the first relay component. Compared with related technologies that use complex circuit designs, it has the advantage of low hardware cost, thus ensuring detection accuracy while reducing hardware costs.

[0164] In the above embodiments, the first relay assembly includes a first relay and a second relay;

[0165] The first relay assembly being in the off state includes: the first relay being in the off state; and / or the second relay being in the off state.

[0166] The first relay assembly being in the off state includes: the first relay being in the off state and the second relay being in the on state; or the second relay being in the off state and the first relay being in the on state.

[0167] In this embodiment, the first relay assembly includes two relays, namely a first relay and a second relay. The first relay and the second relay are connected in series. The first terminal of the first relay serves as the first terminal of the first relay assembly and is connected to the neutral line of the DC neutral line. The second terminal of the second relay serves as the second terminal of the first relay assembly and is connected to the neutral line of the three-phase power supply. The second terminal of the first relay is connected to the first terminal of the second relay.

[0168] The first relay assembly being in the off state includes any of the following: the first relay is in the off state and the second relay is in the on state; the first relay is in the on state and the second relay is in the off state; or both the first relay and the second relay are in the off state.

[0169] In this embodiment, by setting a first relay and a second relay connected in series in the first relay assembly, it is possible to ensure that the DC bus and the three-phase power supply are electrically isolated when the energy storage converter is operating in grid-connected mode. Compared with the scheme of setting only a single relay between the DC bus and the three-phase power supply, it has higher isolation stability.

[0170] In any of the above embodiments, determining the fault state of the first relay assembly based on the first voltage difference and the second voltage difference includes:

[0171] Based on the fact that both the first voltage difference and the second voltage difference are less than a preset threshold, it is determined that the target relay in the first relay assembly is in a fault state. The target relay is the relay in the first relay and the second relay that is in the open state.

[0172] For example, the preset threshold value ranges from 0V to 30V.

[0173] In this embodiment, the first voltage difference is the voltage difference detected between the two ends of the first relay assembly when both the switch and the first relay assembly are in the off state. The second voltage difference is the voltage difference detected between the two ends of the first relay assembly when the switch is in the on state and the first relay assembly is in the off state.

[0174] Due to the design of the grounding system (PE) in the energy storage converter system, there is a possibility of misjudgment if the first relay component is faulty based solely on the first voltage difference or the second voltage difference. However, by switching the on / off state of the switching components and adjusting whether the resistor component is connected between the negative terminal of the DC bus and the grounding system, the possibility of misjudgment can be effectively avoided.

[0175] This embodiment controls one relay in the first relay assembly to be disconnected while the other relay remains on. Based on the first voltage difference and the second voltage difference, it can accurately detect whether the disconnected relay is in a faulty state, thus achieving the effect of precise fault location of the first relay assembly.

[0176] In any of the above embodiments, a second relay assembly is provided between the three-phase input terminal of the energy storage converter and the three-phase power supply;

[0177] Before the control switch is switched from the open state to the on state while the first relay assembly is in the open state, the method further includes: controlling the second relay assembly to be in the open state.

[0178] In this embodiment, the second relay assembly is used to control the on / off state between the three-phase input terminal of the energy storage converter and the three-phase power supply.

[0179] The second relay assembly includes three sets of relays, with at least two relays in each set. The first terminals of the three sets of relays are connected to the three-phase input terminals of the energy storage converter, and the second terminals of the three sets of relays are all connected to the three-phase power supply. The three sets of relays are used to control the on / off state between the three-phase input terminals of the energy storage converter and the three-phase power supply.

[0180] During the process of detecting whether the first relay assembly is faulty through the detection circuit, it is necessary to ensure that the energy storage converter is not in a grid-connected state and the second relay assembly is in an open state, that is, the three-phase power supply and the energy storage converter are disconnected. This improves the accuracy of the detection and avoids the fault caused by connecting the energy storage converter to the three-phase power supply before determining whether the first relay is faulty.

[0181] In any of the above embodiments, obtaining a first voltage difference value when the switching element is in the off state and a second voltage difference value when the switching element is in the on state includes:

[0182] When the switch is in the off state, a first voltage value at the first terminal of the first relay assembly and a second voltage value at the second terminal of the first relay assembly are acquired; a first voltage difference is determined based on the first voltage value and the second voltage value; when the switch is in the on state, a first voltage value and a third voltage value at the first terminal of the first relay assembly and a fourth voltage value at the second terminal of the first relay assembly are acquired; a second voltage difference is determined based on the third voltage value and the fourth voltage value.

[0183] In this embodiment, the detection circuit further includes a first detection element and a second detection element.

[0184] The first detection element is disposed at the first end of the first relay assembly and is used to collect the voltage value at the first end of the first relay assembly; the second detection element is disposed at the second end of the first relay assembly and is used to collect the voltage value at the second end of the first relay assembly.

[0185] In this embodiment, the sampling terminal of the first detection element is connected to the first terminal of the first relay assembly, and the first detection element is capable of detecting the voltage value at the first terminal of the first relay assembly. The sampling terminal of the second detection element is connected to the second terminal of the first relay assembly, and the second detection element is capable of detecting the voltage value at the second terminal of the first relay assembly.

[0186] Both the first and second detection elements are connected to the control device. After the first and second detection elements acquire the voltage values ​​of the first and second terminals of the first relay assembly, they transmit these voltage values ​​to the control device. The control device can calculate the difference between the voltage values ​​of the first and second terminals of the first relay assembly to obtain a first voltage difference or a second voltage difference.

[0187] This embodiment, by setting a first detection element and a second detection element at the first end and the second end of the first detection component respectively, can accurately detect the voltage values ​​at the first end and the second end of the first relay component, thereby ensuring the accuracy of the calculated first voltage difference and second voltage difference.

[0188] Specifically, such as Figure 4 As shown, in any of the above embodiments, the detection method includes:

[0189] Step 402: Simultaneously disconnect the switch, the first relay, and the second relay;

[0190] Step 404: Control the first relay and the switch to open, keep the second relay closed, and record the voltage of V1 as V10 and the voltage of V2 as V20.

[0191] Wherein, V1 is the voltage value of the first terminal of the first relay assembly, that is, the voltage value of the first terminal of the first relay, and V2 is the voltage value of the first terminal of the first relay assembly, that is, the voltage value of the second terminal of the second relay.

[0192] Step 406: Determine whether |V10-V20| < preset threshold. If the result is yes, proceed to step 412; otherwise, proceed to step 408.

[0193] Where |V10-V20| is the first voltage difference when the first relay is in the off state.

[0194] Step 408: Control the second relay and the switch to disconnect, keep the first relay closed, and record the voltage of V1 as V12 and the voltage of V2 as V22;

[0195] Step 410: Determine whether |V12-V22| < preset threshold. If the result is yes, proceed to step 412; otherwise, end the process.

[0196] Where |V12-V22| is the first voltage difference when the second relay is in the off state.

[0197] Step 412: Control the switch to close, and record the voltage of V1 as V11 and the voltage of V2 as V21;

[0198] Step 414: Determine whether |V11-V21| < preset threshold. If the result is yes, proceed to step 416. If the result is no, end the process or proceed to step 408.

[0199] Where |V12-V22| is the second voltage difference when the first relay or the second relay is in the off state.

[0200] Step 416: Output a fault message indicating adhesion of the first relay assembly.

[0201] In this embodiment, during the initial detection phase, the control switch, the first relay, and the second relay are all in the off state.

[0202] To detect whether the first relay has a sticking fault, the first relay and the switch are controlled to be in the open state, and the second relay is in the closed state. At this time, a first voltage difference value is acquired. If the first voltage difference is greater than or equal to a preset threshold, the first relay is determined to be fault-free. If the first voltage difference is less than the preset threshold, the switch is controlled to close, and a second voltage difference value is acquired. If the second voltage difference is greater than or equal to the preset threshold, the first relay is determined to be fault-free. If the second voltage difference is less than the preset threshold, a sticking fault is determined in the first relay.

[0203] If the first relay is found to be fault-free, the system checks for adhesion faults in the second relay. The second relay and the switch are controlled to be in the open state, while the first relay is in the closed state. At this time, a first voltage difference is acquired. If the first voltage difference is greater than or equal to a preset threshold, the second relay is determined to be fault-free. If the first voltage difference is less than the preset threshold, the switch is controlled to close, and a second voltage difference is acquired. If the second voltage difference is greater than or equal to the preset threshold, the second relay is determined to be fault-free. If the second voltage difference is less than the preset threshold, an adhesion fault is determined in the second relay.

[0204] If a sticking fault is detected in either the first relay or the second relay, a sticking fault warning message for the first relay assembly will be output.

[0205] In one embodiment according to this application, such as Figure 5 As shown, a detection device is proposed for the detection circuit in the first aspect described above. The detection device 500 includes:

[0206] Control module 502 is used to control the switching element to switch from the off state to the on state when the first relay assembly is in the off state;

[0207] The acquisition module 504 is used to acquire a first voltage difference value when the switching element is in the off state and a second voltage difference value when the switching element is in the on state. Both the first voltage difference value and the second voltage difference value are voltage differences between the first terminal and the second terminal of the first relay assembly.

[0208] The determination module 506 is used to determine the fault state of the first relay assembly based on the first voltage difference and the second voltage difference.

[0209] This embodiment connects a resistor and a switch in series between the output and ground terminals of the DC bus of the energy storage converter. Before the switch is turned on, a first voltage difference is detected across the first relay assembly; after the switch is turned off, a second voltage difference is detected. Based on these first and second voltage differences, it is possible to accurately determine whether the first relay assembly has a sticking fault. By switching the on / off state of the switch, it is possible to control whether the resistor is connected between the output and ground terminals of the DC bus, thereby adjusting the voltage value of the first relay assembly near the DC bus and avoiding false detections of a sticking fault in the first relay assembly.

[0210] The detection circuit in this embodiment only includes a resistor component and a switch component, and works with control logic to accurately detect whether there is a sticking fault in the first relay component. Compared with related technologies that use complex circuit designs, it has the advantage of low hardware cost, thus ensuring detection accuracy while reducing hardware costs.

[0211] In one embodiment according to this application, such as Figure 6 As shown, a detection component 600 is proposed, including a processor 602 and a memory 604, wherein the memory 604 stores a program or instructions; the processor 602 executes the program or instructions stored in the memory 604 to implement the steps of the detection method as described in any of the above embodiments, and thus has all the beneficial technical effects of the detection method in any of the above embodiments, which will not be elaborated further here.

[0212] In one embodiment of this application, a readable storage medium is provided, on which a program or instructions are stored. When executed by a processor, the program or instructions implement the steps of the detection method as described in any of the above embodiments. Therefore, it possesses all the beneficial technical effects of the detection method in any of the above embodiments, which will not be elaborated further here.

[0213] In one embodiment according to this application, such as Figure 7 As shown, an energy storage system 700 is proposed, including: the detection device 500 in the above embodiments, and / or the detection component 600, and / or the readable storage medium 702 in the above embodiments. Therefore, it has all the beneficial technical effects of the detection device 500, the detection component 600 and / or the readable storage medium 702 defined in the above embodiments, which will not be elaborated further here.

[0214] It should be clarified that in the claims, description, and accompanying drawings of this invention, the term "plural" refers to two or more. Unless otherwise explicitly defined, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description process, not to indicate or imply that the device or element referred to must have the described specific orientation, or be constructed and operated in a specific orientation. Therefore, these descriptions should not be construed as limiting the invention. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection between multiple objects, a detachable connection between multiple objects, or an integral connection; it can be a direct connection between multiple objects or an indirect connection between multiple objects through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this invention can be understood based on the specific circumstances of the above data.

[0215] In the claims, description, and accompanying drawings of this invention, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In the claims, description, and accompanying drawings of this invention, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0216] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A detection circuit for detecting the fault state of a first relay assembly between the neutral line of the DC bus of an energy storage converter and the neutral line of a three-phase power supply, characterized in that, The detection circuit includes: Resistor components; A switching element, wherein the switching element and the resistor assembly are connected in series between the output terminal and the ground terminal of the DC bus; A control device is connected to both the first relay assembly and the switching element, and the control device is used for: When the first relay assembly is in the off state, the switch element is controlled to switch from the off state to the on state; Obtain a first voltage difference value when the switch is in the off state and a second voltage difference value when the switch is in the on state, wherein the first voltage difference value and the second voltage difference value are both voltage differences across the first relay assembly; The fault state of the first relay assembly is determined based on the first voltage difference and the second voltage difference. A second relay assembly is provided between the three-phase input terminal of the energy storage converter and the three-phase power supply. The control device is connected to the second relay assembly; Before controlling the switching element to switch from the off state to the on state while the first relay assembly is in the off state, the control device is further configured to: The second relay assembly is controlled to be in the off state; The second relay assembly includes three sets of relays, with each set containing at least two relays; Specifically, when the first relay assembly is connected to the grid, all relays in the first relay assembly are in the off state.

2. The detection circuit according to claim 1, characterized in that, The first relay assembly includes: a first relay and a second relay, the first relay and the second relay being connected in series, one end of the first relay being connected to the neutral line of the DC bus, and one end of the second relay being connected to the neutral line of the three-phase power supply; The first relay assembly being in the off state includes: The first relay is in the off state; and / or The second relay is in the off state.

3. The detection circuit according to claim 2, characterized in that, The control device determines the fault state of the first relay assembly based on the first voltage difference and the second voltage difference, specifically for: Based on the fact that both the first voltage difference and the second voltage difference are less than a preset threshold, it is determined that the target relay in the first relay assembly is in a fault state. The target relay is the relay that is in the open state among the first relay and the second relay.

4. The detection circuit according to claim 1, characterized in that, Also includes: A capacitive component is disposed between the three-phase input terminal of the energy storage converter and the first relay component.

5. The detection circuit according to any one of claims 1 to 3, characterized in that, Also includes: The first detection element is disposed at the first end of the first relay assembly and is used to collect the voltage value at the first end of the first relay assembly; The second detection element is disposed at the second end of the first relay assembly and is used to collect the voltage value at the second end of the first relay assembly.

6. A detection method for use in the detection circuit according to any one of claims 1 to 5, characterized in that, include: When the first relay assembly is in the off state, the switch element is controlled to switch from the off state to the on state; Obtain a first voltage difference value when the switch is in the off state and a second voltage difference value when the switch is in the on state, wherein the first voltage difference value and the second voltage difference value are both voltage differences between the first terminal and the second terminal of the first relay assembly; The fault state of the first relay assembly is determined based on the first voltage difference and the second voltage difference.

7. The detection method according to claim 6, characterized in that, The first relay assembly includes a first relay and a second relay; The first relay assembly being in the off state includes: the first relay being in the off state; and / or the second relay being in the off state.

8. The detection method according to claim 7, characterized in that, Determining the fault state of the first relay assembly based on the first voltage difference and the second voltage difference includes: Based on the fact that both the first voltage difference and the second voltage difference are less than a preset threshold, it is determined that the target relay in the first relay assembly is in a fault state. The target relay is the relay that is in the open state among the first relay and the second relay.

9. The detection method according to any one of claims 6 to 8, characterized in that, A second relay assembly is provided between the three-phase input terminal of the energy storage converter and the three-phase power supply. Before controlling the switching element to switch from the off state to the on state when the first relay assembly is in the off state, the method further includes: The second relay assembly is controlled to be in the off state.

10. The detection method according to any one of claims 6 to 8, characterized in that, The step of obtaining a first voltage difference value when the switching element is in the off state and a second voltage difference value when the switching element is in the on state includes: When the switch is in the off state, the first voltage value of the first terminal of the first relay assembly and the second voltage value of the second terminal of the first relay assembly are obtained. The first voltage difference is determined based on the first voltage value and the second voltage value; When the switch is in the ON state, the first and third voltage values ​​of the first terminal of the first relay assembly, and the fourth voltage value of the second terminal of the first relay assembly are obtained; The second voltage difference is determined based on the third voltage value and the fourth voltage value.

11. A detection device for use in the detection circuit according to any one of claims 1 to 5, characterized in that, include: The control module is used to control the switching element to switch from the off state to the on state when the first relay assembly is in the off state; The acquisition module is used to acquire a first voltage difference value when the switch is in the off state and a second voltage difference value when the switch is in the on state, wherein the first voltage difference value and the second voltage difference value are both voltage differences between the first terminal and the second terminal of the first relay assembly; The determination module is used to determine the fault state of the first relay assembly based on the first voltage difference and the second voltage difference.

12. A detection component, characterized in that, include: A memory that stores programs or instructions; A processor, configured to implement the steps of the detection method as described in any one of claims 6 to 10 when executing the program or instructions.

13. A readable storage medium having a program or instructions stored thereon, characterized in that, When the program or instructions are executed by the processor, they implement the steps of the detection method as described in any one of claims 6 to 10.

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