Defect detection circuit and method

Abstract

A defect detection circuit and method. By controlling on states and off states of switching elements in a circuit, connection states of the circuit are switched, so as to measure output voltages of a resistor network module (2) and a bridge arm module (3). On the basis of a set of output voltages acquired in different connection states, whether a fault has occurred in the switching elements and loops in the circuit is detected, thereby performing comprehensive detection on an insulation detection circuit, and preventing a fault in circuit components from affecting the accuracy of insulation detection.

Description

A defect detection circuit and method

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Chinese Patent Application No. 202411533290.6, filed on October 29, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of insulation testing technology, and in particular to a defect detection circuit and method. Background Technology

[0004] In electric vehicles and large energy storage battery systems, the voltage is often very high, typically several hundred volts. High voltage safety protection is a very important issue for high voltage battery systems. To prevent electric shock hazards caused by high voltage leakage, the system needs to monitor the insulation resistance value in real time and issue an alarm when the insulation resistance is low.

[0005] The conventional insulation testing method is the bridge method. This method involves connecting a known resistor between the high-voltage positive and negative terminals of the battery system and ground, forming a bridge circuit. By measuring the resistance values ​​of the bridge arms, the insulation resistance between the battery system and ground can be calculated. However, this method can only detect resistance changes within the bridge circuit. For parts outside the bridge circuit, such as the ground switch, it cannot be fully detected. Furthermore, the bridge arms rely on precise resistance adjustment. If a problem occurs in a part of the bridge circuit, it may lead to misjudgment and fail to accurately reflect the insulation status of the entire system.

[0006] Application content

[0007] This application provides a defect detection circuit and method for comprehensive testing of insulation detection circuits, thereby improving the detection accuracy of insulation detection circuits.

[0008] To address the aforementioned technical problems, embodiments of this application provide a defect detection circuit, including:

[0009] Equivalent insulation module, resistor network module, bridge arm module, voltage divider module, first switching element, second switching element and third switching element;

[0010] The first end of the equivalent insulation module is electrically connected to the first end of the resistor network module, the third switching element, and the first end of the bridge arm module; the second end of the equivalent insulation module is electrically connected to the first end of the second switching element and the second end of the bridge arm module; the third end of the equivalent insulation module is electrically connected to the first end of the first switching element, the second end of the resistor network module, and the ground wire.

[0011] The second terminal of the resistor network module is electrically connected to the ground wire and the first terminal of the first switching element.

[0012] The first end of the voltage divider module is electrically connected to the second end of the third switching element; the second end of the voltage divider module is electrically connected to the second end of the second switching element; and the third end of the voltage divider module is electrically connected to the second end of the first switching element and the third end of the bridge arm module.

[0013] This application controls the conduction and closure states of various switching elements in the control circuit to switch the circuit connection state, thereby detecting the output voltage of the resistor network module and bridge arm module. Based on the output voltage collected under different connection states, it detects whether the switching elements and each loop in the detection circuit have faults, thus performing a comprehensive test on the insulation detection circuit and avoiding the impact of circuit component failures on the accuracy of insulation detection.

[0014] Furthermore, the resistor network module includes a first resistor, a second resistor, and a first voltage detection module;

[0015] The first end of the first resistor is the first end of the resistor network module;

[0016] The second end of the first resistor is electrically connected to the first end of the second resistor; and the second end of the first resistor is electrically connected to the first voltage detection module.

[0017] The second end of the second resistor is the second end of the resistor network module.

[0018] Furthermore, the equivalent insulation module includes a first equivalent resistor, a second equivalent resistor, and a power supply module;

[0019] The first end of the first equivalent resistor is electrically connected to the positive terminal of the power module, and is the first end of the equivalent insulation module;

[0020] The second end of the first equivalent resistor is electrically connected to the first end of the second equivalent resistor; and the second end of the first equivalent resistor is the third end of the equivalent insulation module;

[0021] The second end of the second equivalent resistor is electrically connected to the negative terminal of the power supply module, and is the second end of the equivalent insulation module.

[0022] Furthermore, the voltage divider module includes: a third resistor and a fourth resistor;

[0023] The first end of the third resistor is the first end of the voltage divider module;

[0024] The second end of the third resistor is electrically connected to the first end of the fourth resistor, which is the third end of the voltage divider module;

[0025] The second terminal of the fourth resistor is the second terminal of the voltage divider module.

[0026] Furthermore, the bridge arm module includes a fifth resistor, a sixth resistor, a seventh resistor, and a second voltage detection module;

[0027] The first end of the fifth resistor is the first end of the bridge arm module;

[0028] The second end of the fifth resistor is electrically connected to the first end of the sixth resistor, which is the third end of the bridge arm module;

[0029] The second end of the sixth resistor is electrically connected to the first end of the seventh resistor, and the second end of the sixth resistor is also electrically connected to the second voltage detection module.

[0030] The second end of the seventh resistor is the second end of the bridge arm module.

[0031] Furthermore, the defect detection circuit also includes a fourth switching element;

[0032] The fourth switching element is located between the first end of the equivalent insulation module and the first end of the resistor network module.

[0033] Furthermore, the first end of the fourth switching element is electrically connected to the first end of the equivalent insulation module; the second end of the fourth switching element is electrically connected to the first end of the resistor network module.

[0034] Secondly, this application provides a defect detection method applied to the aforementioned defect detection circuit, comprising:

[0035] The on and off states of the first, second, and third switching elements are controlled based on a preset set of switching control sequences.

[0036] The first output voltage of the resistor network module and the second output voltage of the bridge arm module corresponding to the control state of each switch control sequence are obtained, and the circuit is judged to be faulty based on the battery voltage, the first output voltage, the second output voltage and the preset voltage threshold.

[0037] Furthermore, the switch control sequence set includes a first control sequence, a second control sequence, and a third control sequence;

[0038] The first control sequence includes the first switching element, the second switching element, and the third switching element all being in the off state;

[0039] The second control sequence includes the first and second switching elements being in an off state, and the third switching element being in a conducting state;

[0040] The third control sequence includes the first and third switching elements being in an off state, and the second switching element being in a conducting state.

[0041] Furthermore, the step of obtaining the first output voltage of the resistor network module and the second output voltage of the bridge arm module corresponding to the control state of each switch control sequence, and determining whether the circuit is faulty based on the battery voltage, the first output voltage, the second output voltage, and a preset voltage threshold, includes:

[0042] Under the control state of the first control sequence, the first output voltage of the resistor network module and the second output voltage of the bridge arm module are acquired; a first voltage value is calculated based on the first and second output voltages, and a second voltage value is calculated based on the second output voltage; if the first voltage value is not equal to the battery voltage and the second voltage value is not equal to the battery voltage, then a circuit fault is determined.

[0043] Under the control state of the second control sequence, the second output voltage of the bridge arm module is acquired; a third voltage value is calculated based on the second output voltage; if the third voltage value is not equal to the battery voltage, a circuit fault is determined.

[0044] Under the control state of the third control sequence, the second output voltage of the bridge arm module is acquired; a fourth voltage value is calculated based on the second output voltage; if the fourth voltage value is not equal to the battery voltage, a circuit fault is determined.

[0045] Furthermore, the calculation of the first voltage value based on the first output voltage and the second output voltage includes:

[0046] The first voltage value is calculated based on the first output voltage, the second output voltage, and the resistance value of the resistor in the resistor network module.

[0047] Furthermore, the calculation of the second voltage value based on the second output voltage includes:

[0048] The second voltage value is calculated based on the second output voltage and the resistance value of the resistor in the bridge arm module.

[0049] Furthermore, the calculation of the third voltage value based on the second output voltage includes:

[0050] The third voltage value is calculated based on the second output voltage, the resistance value of the resistor through which current flows in the voltage divider module, and the resistance value of the resistor in the bridge arm module.

[0051] Furthermore, the calculation of the fourth voltage value based on the second output voltage includes:

[0052] The third voltage value is calculated based on the second output voltage, the resistance value of the resistor through which current flows in the voltage divider module, and the resistance value of the resistor in the bridge arm module.

[0053] Furthermore, the step of determining a circuit fault if the first voltage value is not equal to the battery voltage and the second voltage value is not equal to the battery voltage includes:

[0054] If the first voltage value is not equal to the battery voltage and the second voltage value is not equal to the battery voltage, then a switching circuit fault is determined in the second and third switching elements. Attached Figure Description

[0055] Figure 1 is a schematic diagram of a defect detection circuit provided in an embodiment of this application;

[0056] Figure 2 is a schematic diagram of a defect detection circuit provided in an embodiment of this application;

[0057] Figure 3 shows another connection diagram of a defect detection circuit provided in an embodiment of this application;

[0058] Figure 4 shows another connection diagram of a defect detection circuit provided in an embodiment of this application;

[0059] Figure 5 is a schematic diagram of a defect detection circuit provided in an embodiment of this application;

[0060] Figure 6 is a flowchart illustrating a defect detection method provided in an embodiment of this application.

[0061] The reference numerals in the accompanying drawings are as follows: 1. Equivalent insulation module; 11. First equivalent resistance; 12. Second equivalent resistance; 13. Power supply module; 2. Resistor network module; 21. First resistor; 22. Second resistor; 23. First voltage detection module; 3. Bridge arm module; 31. Fifth resistor; 32. Sixth resistor; 33. Seventh resistor; 34. Second voltage detection module; 4. Voltage divider module; 41. Third resistor; and 42. Fourth resistor; 5. First switching element; 6. Second switching element; 7. Third switching element; 8. Fourth switching element. Detailed Implementation

[0062] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0063] The terms "first" and "second," etc., in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0064] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0065] Example 1

[0066] Referring to Figure 1, Figure 1 is a schematic diagram of a defect detection circuit provided in an embodiment of this application. This embodiment of the application provides a defect detection circuit, including: an equivalent insulation module 1, a resistor network module 2, a bridge arm module 3, a voltage divider module 4, a first switching element 5, a second switching element 6, and a third switching element 7;

[0067] The first end of the equivalent insulation module 1 is electrically connected to the first end of the resistor network module 2, the third switching element 7, and the first end of the bridge arm module 3; the second end of the equivalent insulation module 1 is electrically connected to the first end of the second switching element 6 and the second end of the bridge arm module 3; the third end of the equivalent insulation module 1 is electrically connected to the first end of the first switching element 5, the second end of the resistor network module 2, and the ground wire.

[0068] The second end of the resistor network module 2 is electrically connected to the ground wire and the first end of the first switching element 5.

[0069] The first end of the voltage divider module 4 is electrically connected to the second end of the third switching element 7; the second end of the voltage divider module 4 is electrically connected to the second end of the second switching element 6; and the third end of the voltage divider module 4 is electrically connected to the second end of the first switching element 5 and the third end of the bridge arm module 3.

[0070] In this embodiment, by switching the switching element, the resistor network module 2 is connected to the circuit, which can detect the connection status between the voltage divider module circuit, the bridge arm module circuit, and the equivalent insulation module 1, and promptly detect potential faults. Through multiple control sequences and voltage measurements, the insulation status of the high-voltage battery system is comprehensively detected, ensuring accurate identification even when problems occur at different locations in the circuit, thereby improving the comprehensiveness and accuracy of the detection.

[0071] In this embodiment, the equivalent insulation module 1 is used to simulate the insulation resistance between the battery system and ground, and its voltage characteristics reflect the insulation status of the actual battery system; the resistor network module 2 is used to provide a resistor network for voltage division and detection of voltage changes; the bridge arm module 3 and the voltage divider module 4 are used to perform voltage division and voltage detection in insulation detection, thereby detecting the insulation status of the insulation resistance.

[0072] In this embodiment, voltage signals at different locations are acquired by controlling the on and off states of three switching elements. Under different circuit connection conditions, the first output voltage of the resistor network module 2 and the second output voltage of the bridge arm module 3 are measured respectively. Calculations are then performed based on the acquired first and second output voltages, and these calculations are compared with the battery voltage to determine whether a fault has occurred.

[0073] In this embodiment, the resistor network module 2 includes a first resistor 21, a second resistor 22, and a first voltage detection module 23;

[0074] The first end of the first resistor 21 is the first end of the resistor network module 2;

[0075] The second end of the first resistor 21 is electrically connected to the first end of the second resistor 22; and the second end of the first resistor 21 is electrically connected to the first voltage detection module 23.

[0076] The second end of the second resistor 22 is the second end of the resistor network module 2.

[0077] In this embodiment, the first end of the first resistor 21 serves as the first end of the resistor network module 2; the second end of the second resistor 22 serves as the second end of the resistor network module 2. In this embodiment, current flows from the positive terminal of the battery, passes through the first end of the equivalent insulation module 1, and enters the first end of the first resistor 21 in the resistor network module 2; the first resistor 21 restricts the current flow, creating a voltage drop. Current flows out from the second end of the first resistor 21, which is simultaneously connected to the first end of the second resistor 22 and the first voltage detection module 23; the second resistor 22 further restricts the current flow and generates another voltage drop; the current finally flows out from the second end of the second resistor 22, which is connected to the third end of the equivalent insulation module 1, the first switching element 5, and the ground wire. The first voltage detection module 23 can detect the voltage value between the first resistor 21 and the second resistor 22, which is the output voltage of the resistor network module 2, i.e., the first output voltage.

[0078] In this embodiment, the first resistor 21, the second resistor 22, and the equivalent insulation module 1 work together to form a voltage divider network, ensuring that the voltage signal can be effectively transmitted to the first voltage detection module. The first voltage detection module is connected to the measurement node, that is, the connection point of the first resistor 21 and the second resistor 22, which can collect an effective voltage signal and at the same time protect the circuit from current surges.

[0079] In this embodiment, the first voltage detection module 23 is a voltmeter ADC1, which is used to collect the voltage at the connection point of the first resistor 21 and the second resistor 22.

[0080] In this embodiment, the equivalent insulation module 1 includes a first equivalent resistor 11, a second equivalent resistor 12, and a power supply module 13;

[0081] The first end of the first equivalent resistor 11 is electrically connected to the positive terminal of the power module 13, and is the first end of the equivalent insulation module 1;

[0082] The second end of the first equivalent resistor 11 is electrically connected to the first end of the second equivalent resistor 12; and the second end of the first equivalent resistor 11 is the third end of the equivalent insulation module 1.

[0083] The second terminal of the second equivalent resistor 12 is electrically connected to the negative terminal of the power module 13, and is the second terminal of the equivalent insulation module 1.

[0084] In this embodiment, the first end of the first equivalent resistor 11 serves as the first end of the equivalent insulation module 1; the second end of the second equivalent resistor 12 serves as the second end of the equivalent insulation module 1; and the second end of the first equivalent resistor 11 serves as the third end of the equivalent insulation module 1.

[0085] In this embodiment, current flows out from the positive terminal of the power module 13, passes through the first end of the first equivalent resistor 11, enters the interior of the first equivalent resistor 11, and continues to flow to the second end of the first equivalent resistor 11. The second end of the first equivalent resistor 11 is connected to the first end of the second equivalent resistor 12. Current flows out from the second end of the first equivalent resistor 11 and enters the first end of the second equivalent resistor 12. Current passes through the second equivalent resistor 12 and finally flows to the second end of the second equivalent resistor 12. Current flows out from the second end of the second equivalent resistor 12, the second end of the second equivalent resistor 12 is connected to the negative terminal of the power module 13, and finally flows back to the negative terminal of the power module 13, completing the circuit.

[0086] In this embodiment, the first equivalent resistance 11 and the second equivalent resistance 12 simulate the insulation resistance between the battery system and ground, forming a resistance network to limit current flow and create a voltage drop. By measuring these voltage drops, the insulation resistance state of the positive and negative terminals of the battery system can be indirectly obtained.

[0087] In this embodiment, the voltage divider module 4 includes: a third resistor 41 and a fourth resistor 42;

[0088] The first end of the third resistor 41 is the first end of the voltage divider module 4;

[0089] The second end of the third resistor 41 is electrically connected to the first end of the fourth resistor 42, which is the third end of the voltage divider module 4;

[0090] The second end of the fourth resistor 42 is the second end of the voltage divider module 4.

[0091] In this embodiment, the first end of the third resistor 41 serves as the first end of the voltage divider module 4; the second end of the fourth resistor 42 serves as the second end of the voltage divider module 4; the second end of the third resistor 41 serves as the third end of the voltage divider module 4 or the first end of the fourth resistor 42 serves as the third end of the voltage divider module 4.

[0092] In this embodiment, the third resistor 41 and the fourth resistor 42 together form a voltage divider network and are connected to the defect detection circuit based on the second switch element 6 and the third switch element 7. By controlling the on and off states of the second switch element 6 and the third switch element 7, the voltage changes in the circuit can be adjusted and detected. By detecting the voltage changes under different paths, the voltage distribution of the circuit can be inferred.

[0093] In this embodiment, the bridge arm module 3 includes a fifth resistor 31, a sixth resistor 32, a seventh resistor 33, and a second voltage detection module 34;

[0094] The first end of the fifth resistor 31 is the first end of the bridge arm module 3;

[0095] The second end of the fifth resistor 31 is electrically connected to the first end of the sixth resistor 32, which is the third end of the bridge arm module 3;

[0096] The second end of the sixth resistor 32 is electrically connected to the first end of the seventh resistor 33, and the second end of the sixth resistor 32 is also electrically connected to the second voltage detection module 34.

[0097] The second end of the seventh resistor 33 is the second end of the bridge arm module 3.

[0098] In this embodiment, the first end of the fifth resistor 31 serves as the first end of the bridge arm module 3, the second end of the seventh resistor 33 serves as the second end of the bridge arm module 3, and the second end of the fifth resistor 31 serves as the third end of the bridge arm module 3.

[0099] In this embodiment, current flows from the positive terminal of power module 13 through the resistors in equivalent insulation module 1 and bridge arm module 3, and finally flows to the negative terminal of power module 13. During this process, the voltage detection module determines the insulation state of the system by detecting the voltage across the resistors. The fifth resistor 31, the sixth resistor 32, and the seventh resistor 33 together form a voltage divider network used to regulate and detect voltage changes in the circuit. By measuring these voltages, the insulation state of the battery system can be inferred. The second voltage detection module 34 is responsible for detecting key voltage values ​​in the voltage divider network and feeding these values ​​back to the control system to determine if an insulation fault exists.

[0100] In this embodiment, the second voltage detection module 34 is a voltmeter ADC2, used to collect the voltage at the connection point of the sixth resistor 32 and the seventh resistor 33.

[0101] In this embodiment, the defect detection circuit further includes a fourth switching element 8.

[0102] The fourth switching element 8 is located between the first end of the equivalent insulation module 1 and the first end of the resistor network module 2.

[0103] In this embodiment, the first end of the fourth switching element 8 is electrically connected to the first end of the equivalent insulation module 1; the second end of the fourth switching element 8 is electrically connected to the first end of the resistor network module 2.

[0104] In this embodiment, when the fourth switching element 8 is not provided, the resistor network module 2 is always connected to the circuit. By controlling the conduction and disconnection of the first switching element 5, the second switching element 6 and the third switching element 7, the insulation resistance of the battery system and the circuit fault detection can be realized.

[0105] In this embodiment, the circuit is connected to the fourth switching element 8, and when the fourth switching element 8 is closed, the resistor network module 2 is also connected to the circuit. By controlling the conduction and disconnection of the first switching element 5, the second switching element 6 and the third switching element 7, the insulation resistance of the battery system and the circuit fault detection are realized.

[0106] In this embodiment, the circuit is connected to the fourth switching element 8, and when the fourth switching element 8 is disconnected, the current cannot flow into the resistor network module 2. Therefore, the circuit is only an insulation detection circuit. By controlling the conduction and disconnection of the second switching element 6 and the third switching element 7, the output voltage of the second voltage detection module 34 is obtained to determine the insulation status of the equivalent insulation resistance.

[0107] This application also provides a defect detection method applied to the aforementioned defect detection circuit, comprising:

[0108] The on and off states of the first switching element 5, the second switching element 6, and the third switching element 7 are controlled based on a preset set of switching control sequences.

[0109] The first output voltage of the resistor network module 2 and the second output voltage of the bridge arm module 3 corresponding to the control state of each switch control sequence are obtained, and the circuit is judged to be faulty based on the battery voltage, the first output voltage, the second output voltage and the preset voltage threshold.

[0110] In this embodiment, the conduction and closing states of multiple switching elements are controlled by a preset switch control sequence. The output voltages of the resistor network module 2 and the bridge arm module 3 are collected and compared with preset voltage thresholds, thereby realizing real-time detection of circuit insulation status and fault judgment.

[0111] In this embodiment, the switch control sequence set includes a first control sequence, a second control sequence, and a third control sequence;

[0112] The first control sequence includes the first switching element 5, the second switching element 6, and the third switching element 7 all being in the off state;

[0113] The second control sequence includes the first switching element 5 and the second switching element 6 being in an off state, and the third switching element 7 being in a conducting state;

[0114] The third control sequence includes the first switching element 5 and the third switching element 7 being in the off state, and the second switching element 6 being in the on state.

[0115] In this embodiment, the step of obtaining the first output voltage of the resistor network module 2 and the second output voltage of the bridge arm module 3 corresponding to the control states of each switch control sequence, and determining whether the circuit is faulty based on the battery voltage, the first output voltage, the second output voltage, and a preset voltage threshold, includes:

[0116] Under the control state of the first control sequence, the first output voltage of the resistor network module 2 and the second output voltage of the bridge arm module 3 are acquired; a first voltage value is calculated based on the first and second output voltages, and a second voltage value is calculated based on the second output voltage; if the first voltage value is not equal to the battery voltage and the second voltage value is not equal to the battery voltage, then the circuit is faulty.

[0117] Under the control state of the second control sequence, the second output voltage of the bridge arm module 3 is acquired; a third voltage value is calculated based on the second output voltage; if the third voltage value is not equal to the battery voltage, then there is a circuit fault.

[0118] Under the control state of the third control sequence, the second output voltage of the bridge arm module 3 is acquired; a fourth voltage value is calculated based on the second output voltage; if the fourth voltage value is not equal to the battery voltage, then the circuit is faulty.

[0119] In this embodiment, several control sequences are preset, which include the on and off control of different switches, thereby adjusting the current flow in the circuit.

[0120] Please refer to Figure 2, which is a schematic diagram of a defect detection circuit provided in an embodiment of this application.

[0121] In this embodiment, the switching elements in the defect detection circuit are controlled by a first control sequence, wherein the first switching element 5, the second switching element 6 and the third switching element 7 are all in an off state.

[0122] In this embodiment, since the first switching element 5 is open, the resistor network module 2 and the resistor network composed of the first equivalent resistor 11 and the second equivalent resistor 12 will not affect the voltage division of the bridge arm module 3; the first output voltage and the second output voltage are collected, and the first voltage value is calculated based on the first output voltage and the second output voltage, and the second voltage value is calculated based on the second output voltage; if the first voltage value is not equal to the battery voltage and the second voltage value is not equal to the battery voltage, then a circuit fault is determined.

[0123] In this embodiment, the first voltage value V1 is specifically: V1 = V p +V n (1)

[0124] In this embodiment, V nThe first output voltage V based on resistor network module 2 x Calculations show that V p Based on the second output voltage V of bridge arm module 3 y Specifically, V was calculated to be: p =V y ·n (2) V n =V x ·n (3)

[0125] Where R1 is the resistance value of the first resistor 21, and R2 is the resistance value of the second resistor 22.

[0126] In this embodiment, the second voltage value V2 is based on the resistance value R5 of the fifth resistor 31, the resistance value R6 of the sixth resistor 32, the resistance value R7 of the seventh resistor 33, and the second output voltage V. y The calculations yielded the following specific results:

[0127] In this embodiment, when both the second switching element 6 and the third switching element 7 are open, if the first switching element 5 is closed, the first voltage value V1 should be equal to the battery voltage V. B If they are equal, then V B =V p +V n If the first switching element 5 is open, only when At that time, V B =V p +V n , where R P R is the resistance value of the first equivalent resistance 11. n This is the resistance value of the second equivalent resistance 12. Therefore, when V B ≠V p +V n When the first switching element 5 is open, it can be confirmed that the first switching element 5 is open. When the first switching element 5 is open, if This indicates a fault in the switching circuit of voltage divider module 4, namely the second switching element 6 and the third switching element 7.

[0128] In this embodiment, please refer to Figure 3, which is another connection diagram of a defect detection circuit provided in this application embodiment.

[0129] In this embodiment, the switching elements in the defect detection circuit are controlled by a second control sequence, wherein the first switching element 5 and the second switching element 6 are in an off state, and the third switching element 7 is in a conducting state.

[0130] In this embodiment, since the first switching element 5 is open, the resistor network module 2 and the resistor network composed of the first equivalent resistor 11 and the second equivalent resistor 12 will not affect the voltage division of the bridge arm module 3; the second output voltage of the bridge arm module 3 is collected; the third voltage value is calculated based on the second output voltage; if the third voltage value is not equal to the battery voltage, a circuit fault is determined.

[0131] In this embodiment, the third voltage value V3 is calculated based on the second output voltage, the third resistor 41, the fifth resistor 31, the sixth resistor 32, and the seventh resistor 33. Specifically:

[0132] In this embodiment, if This indicates a fault in the control circuit of the third switching element 7.

[0133] Please refer to Figure 4, which is a schematic diagram of another connection of a defect detection circuit provided in an embodiment of this application.

[0134] In this embodiment, the switching elements in the defect detection circuit are controlled by a second control sequence, wherein the first switching element 5 and the third switching element 7 are in an off state, and the second switching element 6 is in a conducting state.

[0135] In this embodiment, since the first switching element 5 is open, the resistor network module 2 and the resistor network composed of the first equivalent resistor 11 and the second equivalent resistor 12 will not affect the voltage division of the bridge arm module 3; the second output voltage of the bridge arm module 3 is collected; the fourth voltage value is calculated based on the second output voltage; if the fourth voltage value is not equal to the battery voltage, a circuit fault is determined.

[0136] In this embodiment, the fourth voltage value is calculated based on the second output voltage, the fourth resistor 42, the fifth resistor 31, the sixth resistor 32, and the seventh resistor 33. Specifically:

[0137] In this embodiment, if This indicates a fault in the control circuit of the second switching element 6.

[0138] In this embodiment, by controlling the on and off states of each switching element in the control circuit, the circuit connection state is switched, thereby detecting the output voltage of the resistor network module 2 and the bridge arm module 3. Based on the output voltage collected under different connection states, the switching elements and each loop in the detection circuit are checked for faults, thereby performing a comprehensive test on the insulation detection circuit and avoiding the impact of circuit component failures on the accuracy of insulation detection.

[0139] Please refer to Figures 5 and 6. Figure 5 is a structural schematic diagram of a defect detection circuit provided in an embodiment of this application, and Figure 6 is a flowchart of a defect detection method provided in an embodiment of this application.

[0140] In this embodiment, a defect detection circuit includes: an equivalent insulation module 1, a resistor network module 2, a bridge arm module 3, a voltage divider module 4, a first switching element 5, a second switching element 6, a third switching element 7, and a fourth switching element 8.

[0141] The first end of the equivalent insulation module 1 is electrically connected to the first end of the resistor network module 2, the third switching element 7, and the first end of the bridge arm module 3; the second end of the equivalent insulation module 1 is electrically connected to the first end of the second switching element 6 and the second end of the bridge arm module 3; the third end of the equivalent insulation module 1 is electrically connected to the first end of the first switching element 5, the second end of the resistor network module 2, and the ground wire.

[0142] The equivalent insulation module 1 includes a first equivalent resistor 11, a second equivalent resistor 12, and a power module 13; the first end of the first equivalent resistor 11 is electrically connected to the positive terminal of the power module 13, which is the first end of the equivalent insulation module 1; the second end of the first equivalent resistor 11 is electrically connected to the first end of the second equivalent resistor 12; and the second end of the first equivalent resistor 11 is the third end of the equivalent insulation module 1; the second end of the second equivalent resistor 12 is electrically connected to the negative terminal of the power module 13, which is the second end of the equivalent insulation module 1.

[0143] The resistor network module 2 includes a first resistor 21, a second resistor 22, and a first voltage detection module 23; the first end of the first resistor 21 is the first end of the resistor network module 2; the second end of the first resistor 21 is electrically connected to the first end of the second resistor 22; and the second end of the first resistor 21 is electrically connected to the first voltage detection module 23; the second end of the second resistor 22 is the second end of the resistor network module 2.

[0144] The voltage divider module 4 includes a third resistor 41 and a fourth resistor 42; the first end of the third resistor 41 is the first end of the voltage divider module 4; the second end of the third resistor 41 is electrically connected to the first end of the fourth resistor 42, and is the third end of the voltage divider module 4; the second end of the fourth resistor 42 is the second end of the voltage divider module 4.

[0145] The bridge arm module 3 includes a fifth resistor 31, a sixth resistor 32, a seventh resistor 33, and a second voltage detection module 34; the first end of the fifth resistor 31 is the first end of the bridge arm module 3; the second end of the fifth resistor 31 is electrically connected to the first end of the sixth resistor 32, and is the third end of the bridge arm module 3; the second end of the sixth resistor 32 is electrically connected to the first end of the seventh resistor 33, and the second end of the sixth resistor 32 is also electrically connected to the second voltage detection module 34; the second end of the seventh resistor 33 is the second end of the bridge arm module 3.

[0146] The fourth switching element 8 is located between the first end of the equivalent insulation module 1 and the first end of the resistor network module 2.

[0147] In this embodiment, when performing defect detection based on the defect detection circuit, the fourth switching element 8 (S1) is first closed, and the first switching element 5 (SG), the second switching element 6 (S2), and the third switching element 7 (S3) are opened. At this time, V is calculated based on the first output voltage. n V is calculated based on the second output voltage. p And determine V p +V n Is it equal to the battery voltage V? B .

[0148] If V B =V p +V n Then calculate the second voltage value V2. If the second voltage value V2 is equal to the battery voltage V... B Then close the third switching element 7, and calculate the third voltage value V3 and the fifth voltage value V5. Compare the third voltage value V3 and the fifth voltage value V5. When V... B ≠V p +V n If V3 = V5, then the third switch element 7 is disconnected and the second switch element 6 is closed; otherwise, the circuit is faulty.

[0149] If V B ≠V p +V n If the first switching element 5 is open, then the second voltage value V2 is calculated. If the second voltage value V2 is equal to the battery voltage V... B Then close the third switching element 7, and calculate the third voltage value V3 and the fifth voltage value V5. Compare the third voltage value V3 and the fifth voltage value V5. When V... B ≠V p +V n If V3 = V5, then the third switch element 7 is disconnected and the second switch element 6 is closed; otherwise, the circuit is faulty.

[0150] After the third switching element 7 is disconnected and the second switching element 6 is closed, the fifth voltage value V5 and the fourth voltage value V4 are calculated. When the fifth voltage value V5 and the fourth voltage value V4 are equal, that is... At that time, the first switching element 5 is closed, and V is calculated again. p and V n And determine V p +V n Is it equal to the battery voltage if and only if V p +V n =V B At that time, the circuit self-test was normal.

[0151] In this embodiment, by controlling the on and off states of each switching element in the control circuit, the circuit connection state is switched, thereby detecting the output voltage of the resistor network module 2 and the bridge arm module 3. Based on the output voltage collected under different connection states, the switching elements and each loop in the detection circuit are checked for faults, thereby performing a comprehensive test on the insulation detection circuit and avoiding the impact of circuit component failures on the accuracy of insulation detection.

[0152] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application for those skilled in the art.

Claims

1. A defect detection circuit, wherein, include: Equivalent insulation module (1), resistor network module (2), bridge arm module (3), voltage divider module (4), first switching element (5), second switching element (6) and third switching element (7); The first end of the equivalent insulation module (1) is electrically connected to the first end of the resistor network module (2), the third switching element (7), and the first end of the bridge arm module (3); the second end of the equivalent insulation module (1) is electrically connected to the first end of the second switching element (6) and the second end of the bridge arm module (3); the third end of the equivalent insulation module (1) is electrically connected to the first end of the first switching element (5), the second end of the resistor network module (2), and the ground wire. The second end of the resistor network module (2) is electrically connected to the ground wire and the first end of the first switching element (5); The first end of the voltage divider module (4) is electrically connected to the second end of the third switching element (7); the second end of the voltage divider module (4) is electrically connected to the second end of the second switching element (6); the third end of the voltage divider module (4) is electrically connected to the second end of the first switching element (5) and the third end of the bridge arm module (3).

2. The defect detection circuit as described in claim 1, wherein, The resistor network module (2) includes a first resistor (21), a second resistor (22), and a first voltage detection module (23); The first end of the first resistor (21) is the first end of the resistor network module (2); The second end of the first resistor (21) is electrically connected to the first end of the second resistor (22); and the second end of the first resistor (21) is electrically connected to the first voltage detection module (23); The second end of the second resistor (22) is the second end of the resistor network module (2).

3. The defect detection circuit as described in claim 2, wherein, The equivalent insulation module (1) includes a first equivalent resistor (11), a second equivalent resistor (12), and a power supply module (13); The first end of the first equivalent resistor (11) is electrically connected to the positive terminal of the power module (13), which is the first end of the equivalent insulation module (1); The second end of the first equivalent resistor (11) is electrically connected to the first end of the second equivalent resistor (12); and the second end of the first equivalent resistor (11) is the third end of the equivalent insulation module (1); The second end of the second equivalent resistor (12) is electrically connected to the negative terminal of the power supply module (13), which is the second end of the equivalent insulation module (1).

4. A defect detection circuit as described in claim 3, wherein, The voltage divider module (4) includes: a third resistor (41) and a fourth resistor (42); The first end of the third resistor (41) is the first end of the voltage divider module (4); The second end of the third resistor (41) is electrically connected to the first end of the fourth resistor (42), which is the third end of the voltage divider module (4); The second end of the fourth resistor (42) is the second end of the voltage divider module (4).

5. A defect detection circuit as described in claim 4, wherein, The bridge arm module (3) includes a fifth resistor (31), a sixth resistor (32), a seventh resistor (33), and a second voltage detection module (34); The first end of the fifth resistor (31) is the first end of the bridge arm module (3); The second end of the fifth resistor (31) is electrically connected to the first end of the sixth resistor (32), which is the third end of the bridge arm module (3); The second end of the sixth resistor (32) is electrically connected to the first end of the seventh resistor (33), and the second end of the sixth resistor (32) is also electrically connected to the second voltage detection module (34); The second end of the seventh resistor (33) is the second end of the bridge arm module (3).

6. A defect detection circuit as described in claim 1, wherein, The defect detection circuit also includes a fourth switching element (8); The fourth switching element (8) is located between the first end of the equivalent insulation module (1) and the first end of the resistor network module (2).

7. A defect detection circuit as described in claim 6, wherein, The first end of the fourth switching element (8) is electrically connected to the first end of the equivalent insulation module (1); the second end of the fourth switching element (8) is electrically connected to the first end of the resistor network module (2).

8. A defect detection method, wherein, An application to a defect detection circuit as described in any one of claims 1 to 7, comprising: The on and off states of the first, second, and third switching elements are controlled based on a preset set of switching control sequences. The system obtains the first output voltage of the resistor network module and the second output voltage of the bridge arm module corresponding to the control state of each switch control sequence, and determines whether the circuit is faulty based on the battery voltage, the first output voltage, the second output voltage and the preset voltage threshold.

9. A defect detection method as described in claim 8, wherein, The switch control sequence set includes a first control sequence, a second control sequence, and a third control sequence; The first control sequence includes the first switching element, the second switching element, and the third switching element all being in an off state; The second control sequence includes the first and second switching elements being in an off state, and the third switching element being in a conducting state; The third control sequence includes the first and third switching elements being in an off state, and the second switching element being in a conducting state.

10. A defect detection method as described in claim 9, wherein, The step of obtaining the first output voltage of the resistor network module and the second output voltage of the bridge arm module corresponding to the control state of each switch control sequence, and determining whether the circuit is faulty based on the battery voltage, the first output voltage, the second output voltage, and a preset voltage threshold, includes: Under the control state of the first control sequence, the first output voltage of the resistor network module and the second output voltage of the bridge arm module are acquired; a first voltage value is calculated based on the first output voltage and the second output voltage, and a second voltage value is calculated based on the second output voltage; if the first voltage value is not equal to the battery voltage and the second voltage value is not equal to the battery voltage, then a circuit fault is determined. Under the control state of the second control sequence, the second output voltage of the bridge arm module is acquired; a third voltage value is calculated based on the second output voltage; if the third voltage value is not equal to the battery voltage, a circuit fault is determined. Under the control state of the third control sequence, the second output voltage of the bridge arm module is acquired; a fourth voltage value is calculated based on the second output voltage; if the fourth voltage value is not equal to the battery voltage, a circuit fault is determined.

11. A defect detection method as described in claim 10, wherein, The calculation of the first voltage value based on the first output voltage and the second output voltage includes: The first voltage value is calculated based on the first output voltage, the second output voltage, and the resistance value of the resistor in the resistor network module.

12. A defect detection method as described in claim 11, wherein, The calculation of the second voltage value based on the second output voltage includes: The second voltage value is calculated based on the second output voltage and the resistance value of the resistor in the bridge arm module.

13. A defect detection method as described in claim 10, wherein, The calculation of the third voltage value based on the second output voltage includes: The third voltage value is calculated based on the second output voltage, the resistance value of the resistor through which current flows in the voltage divider module, and the resistance value of the resistor in the bridge arm module.

14. A defect detection method as described in claim 10, wherein, The calculation of the fourth voltage value based on the second output voltage includes: The third voltage value is calculated based on the second output voltage, the resistance value of the resistor through which current flows in the voltage divider module, and the resistance value of the resistor in the bridge arm module.

15. A defect detection method as described in claim 10, wherein, The step of determining a circuit fault if the first voltage value is not equal to the battery voltage and the second voltage value is not equal to the battery voltage includes: If the first voltage value is not equal to the battery voltage and the second voltage value is not equal to the battery voltage, then a switching circuit fault is determined in the second and third switching elements.

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