Defect detection circuit and method

Abstract

The invention discloses a defect detection circuit and method, and the method comprises the steps: switching the connection state of a circuit through controlling the connection state and the closing state of each switching element in the circuit, thereby detecting the output voltage of a resistor network module and a bridge arm module; whether the switch element and each loop in the circuit break down or not is detected based on the output voltage collected in different connection states, so that the insulation detection circuit is comprehensively detected, and the situation that the accuracy of insulation detection is affected by circuit component faults is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of insulation detection, and in particular to a defect detection circuit and method. Background Art

[0002] In electric vehicles and large energy storage battery systems, the voltage is often very high, generally several hundred volts. High-voltage safety protection is a very important issue in high-voltage battery systems. To prevent the risk of electric shock caused by high-voltage leakage, the system needs to detect the insulation resistance value in real time and issue an alarm when the insulation resistance is low.

[0003] The conventional insulation detection method is the bridge method, which forms a bridge circuit by connecting a known resistor between the high-voltage positive and negative poles of the battery system and the ground. The insulation resistance between the battery system and the ground is calculated by measuring the resistance value of the bridge arm. However, this method can only detect resistance changes within the bridge circuit. For parts that are not in the bridge circuit, such as the ground switch, comprehensive detection cannot be performed. In addition, the bridge arm relies on precise resistance adjustment. If there is a problem in a part of the bridge circuit, it may lead to misjudgment and fail to accurately reflect the insulation status of the entire system. Summary of the invention

[0004] The present invention provides a defect detection circuit and method, which are used to perform comprehensive detection on an insulation detection circuit and improve the detection accuracy of the insulation detection circuit.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a defect detection circuit, including:

[0006] An equivalent insulation module, a resistance network module, a bridge arm module, a voltage dividing module, a first switch element, a second switch element and a third switch element;

[0007] The first end of the equivalent insulation module is electrically connected to the first end of the resistance network module, the third switch element and the first end of the bridge arm module; the second end of the equivalent insulation module is electrically connected to the second switch element and the second end of the bridge arm module; the third end of the equivalent insulation module is electrically connected to the first switch element, the resistance network module and the ground wire;

[0008] The first end of the resistor network module is electrically connected to the third switch element and the first end of the bridge arm module respectively; the second end of the resistor network module is electrically connected to the ground line and the first switch element;

[0009] The first end of the voltage divider module is electrically connected to the third switch element; the second end of the voltage divider module is electrically connected to the second switch element; the third end of the voltage divider module is electrically connected to the first switch element and the third end of the bridge arm module;

[0010] The first end of the bridge arm module is electrically connected to the third switch element; the second end of the bridge arm module is electrically connected to the second switch element.

[0011] The present invention switches the circuit connection state by controlling the on-state and the closed-state of each switch element in the circuit, thereby detecting the output voltage of the resistor network module and the bridge arm module, and detecting whether the switch elements and each loop in the circuit are faulty based on the output voltage set collected under different connection states, thereby performing a comprehensive detection on the insulation detection circuit to prevent the circuit component failure from affecting the accuracy of the insulation detection.

[0012] Further, the resistor network module includes a first resistor, a second resistor and a first voltage detection module;

[0013] The first end of the first resistor is electrically connected to the first end of the equivalent insulation module, the third switch element and the first end of the bridge arm module;

[0014] 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;

[0015] The first end of the second resistor is electrically connected to the first voltage detection module;

[0016] The second end of the second resistor is electrically connected to the third end of the equivalent insulation module, the first switch element and the ground wire.

[0017] Furthermore, the equivalent insulation module includes a first equivalent resistor, a second equivalent resistor and a power supply module;

[0018] The first end of the first equivalent resistor is electrically connected to the positive terminal of the power module, the first end of the first resistor, the first end of the bridge arm module and the third switch element;

[0019] 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 electrically connected to the second end of the second resistor, a ground line, and a first switch element;

[0020] The second end of the second equivalent resistor is electrically connected to the negative terminal of the power module, the second end of the bridge arm module and the second switch element;

[0021] The positive terminal of the power module is electrically connected to the first end of the first resistor, the first end of the bridge arm module and the third switch element;

[0022] The negative terminal of the power module is electrically connected to the second switch element and the bridge arm module.

[0023] Further, the voltage dividing module includes: a third resistor and a fourth resistor;

[0024] The first end of the third resistor is electrically connected to the third switch element;

[0025] The second end of the third resistor is electrically connected to the first switch element and the third end of the bridge arm module; the second end of the third resistor is electrically connected to the first end of the fourth resistor;

[0026] The first end of the fourth resistor is electrically connected to the first switch element; the first end of the fourth resistor is electrically connected to the third end of the bridge arm module;

[0027] The second end of the fourth resistor is electrically connected to the second switch element.

[0028] Further, the bridge arm module includes a fifth resistor, a sixth resistor, a seventh resistor and a second voltage detection module;

[0029] The first end of the fifth resistor is electrically connected to the third switch element, the first end of the first resistor, the first end of the first equivalent resistor and the positive terminal of the power module;

[0030] The second end of the fifth resistor is electrically connected to the first end of the sixth resistor; the second end of the fifth resistor is electrically connected to the second end of the third resistor, the first end of the fourth resistor and the first switch element;

[0031] The first end of the sixth resistor is electrically connected to the second end of the third resistor, the first end of the fourth resistor and the first switch element;

[0032] 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 electrically connected to the second voltage detection module;

[0033] The first end of the seventh resistor is electrically connected to the second voltage detection module;

[0034] The second end of the seventh resistor is electrically connected to the second switch element, the second end of the second equivalent resistor and the positive terminal of the power module.

[0035] Further, the defect detection circuit also includes a fourth switch element;

[0036] The first end of the fourth switch element is electrically connected to the first end of the equivalent insulation module, the third switch element and the first end of the bridge arm module; the second end of the fourth switch element is electrically connected to the first end of the resistance network module.

[0037] Furthermore, the first end of the fourth switch element is electrically connected to the first end of the first equivalent resistor, the positive terminal of the power module, the third switch element and the first end of the fifth resistor; the first end of the fourth switch element is electrically connected to the first end of the first resistor.

[0038] In a second aspect, the present invention provides a defect detection method, which is applied to the defect detection circuit, comprising:

[0039] Controlling the on state and the closed state of the first switch element, the second switch element, and the third switch element based on a preset switch control sequence set;

[0040] The first output voltage of the resistor network module and the second output voltage of the bridge arm module are obtained based on each switch control sequence, and whether the circuit is faulty is determined based on the battery voltage, the first output voltage, the second output voltage and a preset voltage threshold.

[0041] Further, the switch control sequence set includes a first control sequence, a second control sequence and a third control sequence;

[0042] The first control sequence includes the first switch element, the second switch element and the third switch element being all in an off state;

[0043] The second control sequence includes the first switch element and the second switch element being in an off state, and the third switch element being in an on state;

[0044] The third control sequence includes the first switch element and the third switch element being in an off state, and the second switch element being in an on state.

[0045] Further, the obtaining of the first output voltage of the resistor network module and the second output voltage of the bridge arm module based on each switch control sequence, and judging whether the circuit is faulty based on the battery voltage, the first output voltage, the second output voltage and a preset voltage threshold, includes:

[0046] Under a first control sequence, collecting a first output voltage of the resistor network module and a second output voltage of the bridge arm module; calculating a first voltage value based on the first output voltage and the second output voltage, and calculating a second voltage value 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, the circuit fails;

[0047] collecting a second output voltage of the bridge arm module under a second control sequence; calculating a third voltage value based on the second output voltage, and if the third voltage value is not equal to the battery voltage, a circuit fault occurs;

[0048] The second output voltage of the bridge arm module is collected under the third control sequence; a fourth voltage value is calculated based on the second output voltage, and if the fourth voltage value is not equal to the battery voltage, the circuit fails. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of a module of a defect detection circuit provided by an embodiment of the present invention;

[0050] Figure 2 A connection diagram of a defect detection circuit provided by an embodiment of the present invention;

[0051] Figure 3 Another connection diagram of a defect detection circuit provided by an embodiment of the present invention;

[0052] Figure 4 Another connection diagram of a defect detection circuit provided by an embodiment of the present invention;

[0053] Figure 5 A schematic diagram of the structure of a defect detection circuit provided by an embodiment of the present invention;

[0054] Figure 6 A schematic flow chart of a defect detection method provided by an embodiment of the present invention.

[0055] The reference numerals of the drawings in the specification are as follows:

[0056] 1. Equivalent insulation module, 11. First equivalent resistor, 12. Second equivalent resistor, 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 switch element, 6. Second switch element, 7. Third switch element, 8. Fourth switch element. DETAILED DESCRIPTION

[0057] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0058] The terms "first" and "second" and the like in the specification, claims and drawings of this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising 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 these processes, methods, products or devices.

[0059] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0060] Example 1

[0061] See also Figure 1 , Figure 1 A schematic diagram of a defect detection circuit provided by an embodiment of the present invention. The present invention provides a defect detection circuit, comprising: an equivalent insulation module 1, a resistor network module 2, a bridge arm module 3, a voltage divider module 4, a first switch element 5, a second switch element 6 and a third switch element 7;

[0062] The first end of the equivalent insulation module 1 is electrically connected to the first end of the resistance network module 2, the third switch 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 second switch 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 switch element 5, the resistance network module 2 and the ground wire;

[0063] The first end of the resistor network module 2 is electrically connected to the third switch element 7 and the first end of the bridge arm module 3 respectively; the second end of the resistor network module 2 is electrically connected to the ground wire and the first switch element 5;

[0064] The first end of the voltage dividing module 4 is electrically connected to the third switch element 7; the second end of the voltage dividing module 4 is electrically connected to the second switch element 6; the third end of the voltage dividing module 4 is electrically connected to the first switch element 5 and the third end of the bridge arm module 3;

[0065] The first end of the bridge arm module 3 is electrically connected to the third switch element 7 ; the second end of the bridge arm module 3 is electrically connected to the second switch element 6 .

[0066] In this embodiment, by switching the switch element and connecting the resistor network module 2 to the circuit, the connection status between the voltage divider circuit, the bridge arm circuit and the equivalent insulation module 1 can be detected, and potential faults can be discovered in time. Through multiple control sequences and voltage measurements, the insulation status of the high-voltage battery system is fully detected to ensure that problems can be accurately identified when they occur at different locations in the circuit, thereby improving the comprehensiveness and accuracy of the detection.

[0067] In this embodiment, the equivalent insulation module 1 is used to simulate the insulation resistance between the battery system and the ground, and its voltage characteristics reflect the insulation condition of the actual battery system; the resistance network module 2 is used to provide a resistance network for voltage division and detection of voltage changes; the bridge arm module 3 and the voltage division module 4 are used to perform voltage division and voltage detection during insulation detection, thereby detecting the insulation condition of the insulation resistance.

[0068] In this embodiment, the on and off states of the three switch elements are controlled to collect voltage signals at different positions. 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, and the first output voltage and the second output voltage obtained by the collection are calculated and compared with the battery voltage to determine whether a fault occurs.

[0069] In this embodiment, the resistor network module 2 includes a first resistor 21, a second resistor 22 and a first voltage detection module 23;

[0070] The first end of the first resistor 21 is electrically connected to the first end of the equivalent insulation module 1, the third switch element 7 and the first end of the bridge arm module 3;

[0071] 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;

[0072] The first end of the second resistor 22 is electrically connected to the first voltage detection module 23;

[0073] The second end of the second resistor 22 is electrically connected to the third end of the equivalent insulation module 1 , the first switch element 5 , and the ground wire.

[0074] 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, the current flows out from the positive electrode of the battery, passes through the first end of the equivalent insulation module 1, and enters the first end of the first resistor 21 of the resistor network module 2; the first resistor 21 limits the flow of current and forms a voltage drop. The current flows out from the second end of the first resistor 21, and the second end of the first resistor 21 is simultaneously connected to the first end of the second resistor 22 and the first voltage detection module 23; the second resistor 22 further limits the flow of current and generates another voltage drop; the current finally flows out from the second end of the second resistor 22, and the second end of the second resistor 22 is connected to the third end of the equivalent insulation module 1, the first switch element 5 and the ground wire. Among them, 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, that is, the first output voltage.

[0075] 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 to ensure that the voltage signal can be effectively transmitted to the first detection module. The voltage detection module enables the measurement node, that is, the connection between the first resistor 21 and the second resistor 22, to collect a valid voltage signal while protecting the circuit from current shock.

[0076] In this embodiment, the first voltage detection module 23 is a voltage meter ADC1, which is used to collect the voltage at the connection point between the first resistor 21 and the second resistor 22.

[0077] In this embodiment, the equivalent insulation module 1 includes a first equivalent resistor 11, a second equivalent resistor 12 and a power module 13;

[0078] The first end of the first equivalent resistor 11 is electrically connected to the positive terminal of the power module 13, the first end of the first resistor 21, the first end of the bridge arm module 3 and the third switch element 7;

[0079] 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 electrically connected to the second end of the second resistor 22, the ground wire and the first switch element 5;

[0080] The second end of the second equivalent resistor 12 is electrically connected to the negative terminal of the power module 13, the second end of the bridge arm module 3 and the second switch element 6;

[0081] The positive terminal of the power module 13 is electrically connected to the first end of the first resistor 21, the first end of the bridge arm module 3 and the third switch element 7;

[0082] The negative terminal of the power module 13 is electrically connected to the second switch element 6 and the bridge arm module 3 .

[0083] 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 .

[0084] In this embodiment, the current flows out from the positive terminal of the power module 13, passes through the first terminal of the first equivalent resistor 11, enters the inside of the first equivalent resistor 11, and continues to flow to the second terminal of the first equivalent resistor 11, and the second terminal of the first equivalent resistor 11 is connected to the first terminal of the second equivalent resistor 12; the current flows out from the second terminal of the first equivalent resistor 11, enters the first terminal of the second equivalent resistor 12; the current passes through the second equivalent resistor 12, and finally flows to the second terminal of the second equivalent resistor 12. The current flows out from the second terminal of the second equivalent resistor 12, and the second terminal 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 loop.

[0085] In this embodiment, the insulation resistance between the battery system and the ground is simulated by the first equivalent resistor 11 and the second equivalent resistor 12, which together form a resistor network to limit the flow of current and form a voltage drop. By measuring these voltage drops, the insulation resistance state of the positive and negative sides of the battery system can be indirectly obtained.

[0086] In this embodiment, the voltage dividing module 4 includes: a third resistor 41 and a fourth resistor 42;

[0087] The first end of the third resistor 41 is electrically connected to the third switch element 7;

[0088] The second end of the third resistor 41 is electrically connected to the first switch element 5 and the third end of the bridge arm module 3; the second end of the third resistor 41 is electrically connected to the first end of the fourth resistor 42;

[0089] The first end of the fourth resistor 42 is electrically connected to the first switch element 5; the first end of the fourth resistor 42 is electrically connected to the third end of the bridge arm module 3;

[0090] A second end of the fourth resistor 42 is electrically connected to the second switch element 6 .

[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; and the first end of the fourth resistor 42 serves as the fourth 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 state and the off state of the second switch element 6 and the third switch element 7, the voltage changes in the circuit are adjusted and detected. By detecting the voltage changes in 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 electrically connected to the third switch element 7, the first end of the first resistor 21, the first end of the first equivalent resistor 11 and the positive terminal of the power module 13;

[0095] The second end of the fifth resistor 31 is electrically connected to the first end of the sixth resistor 32; the second end of the fifth resistor 31 is electrically connected to the second end of the third resistor 41, the first end of the fourth resistor 42 and the first switch element 5;

[0096] The first end of the sixth resistor 32 is electrically connected to the second end of the third resistor 41 , the first end of the fourth resistor 42 , and the first switch element 5 ;

[0097] 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 electrically connected to the second voltage detection module 34 ;

[0098] The first end of the seventh resistor 33 is electrically connected to the second voltage detection module 34;

[0099] The second end of the seventh resistor 33 is electrically connected to the second end of the second equivalent resistor 12 of the second switch element 6 and the positive terminal of the power module 13 .

[0100] 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 .

[0101] In this embodiment, the current flows from the positive terminal of the power module 13 through the resistors in the equivalent insulation module 1 and the bridge arm module 3, and finally flows to the negative terminal of the power module 13. In this process, the voltage detection module determines the insulation state of the system by detecting the voltage across the resistor. Among them, the fifth resistor 31, the sixth resistor 32 and the seventh resistor 33 together constitute a voltage divider network for adjusting and detecting 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 the key voltage value in the voltage divider network, and feeding the voltage value back to the control system to determine whether there is an insulation fault.

[0102] In this embodiment, the second voltage detection module 34 is a voltage meter ADC2, which is used to collect the voltage at the connection point between the sixth resistor 32 and the seventh resistor 33.

[0103] In this embodiment, the defect detection circuit further includes a fourth switch element 8 .

[0104] The first end of the fourth switch element 8 is electrically connected to the first end of the equivalent insulation module 1 , the third switch element 7 and the first end of the bridge arm module 3 ; the second end of the fourth switch element 8 is electrically connected to the first end of the resistance network module 2 .

[0105] In this embodiment, the first end of the fourth switching element 8 is electrically connected to the first end of the first equivalent resistor 11, the positive end of the power module 13, the third switching element 7 and the first end of the fifth resistor 31; the first end of the fourth switching element 8 is electrically connected to the first end of the first resistor 21.

[0106] In this embodiment, when the circuit is not connected to the fourth switch element 8, the resistance network module 2 in the circuit is always connected to the circuit, and the insulation resistance of the battery system and the circuit fault detection are realized by controlling the conduction and disconnection of the first switch element 5, the second switch element 6 and the third switch element 7.

[0107] In this embodiment, the circuit is connected to the fourth switch element 8, and when the fourth switch element 8 is closed, the resistance network module 2 is also connected to the circuit. By controlling the conduction and disconnection of the first switch element 5, the second switch element 6 and the third switch element 7, the insulation resistance of the battery system and the circuit fault detection are realized.

[0108] In this embodiment, the circuit is connected to the fourth switch element 8, and when the fourth switch element 8 is disconnected, the current cannot flow into the resistance network module 2, so the circuit is only an insulation detection circuit, and the insulation condition of the equivalent insulation resistance is judged by controlling the conduction and disconnection of the second switch element 6 and the third switch element 7 and obtaining the output voltage of the second voltage detection module 34.

[0109] The present invention also provides a defect detection method, which is applied to the defect detection circuit, and comprises:

[0110] Controlling the on state and the closed state of the first switch element 5, the second switch element 6 and the third switch element 7 based on a preset switch control sequence set;

[0111] The first output voltage of the resistor network module 2 and the second output voltage of the bridge arm module 3 are obtained based on each switch control sequence, and whether the circuit is faulty is determined based on the battery voltage, the first output voltage, the second output voltage and a preset voltage threshold.

[0112] In this embodiment, a preset switch control sequence is used to control the on and off states of multiple switch elements, collect the output voltages of the resistor network module 2 and the bridge arm module 3, and compare them with the preset voltage threshold, thereby achieving real-time detection of the circuit insulation state and fault judgment.

[0113] In this embodiment, the switch control sequence set includes a first control sequence, a second control sequence and a third control sequence;

[0114] The first control sequence includes the first switch element 5, the second switch element 6 and the third switch element 7 being in an off state;

[0115] The second control sequence includes the first switch element 5 and the third switch element 7 being in an off state, and the second switch element 6 being in an on state;

[0116] The third control sequence includes the first switch element 5 and the second switch element 6 being in an off state, and the third switch element 7 being in an on state.

[0117] In this embodiment, the first output voltage of the resistor network module 2 and the second output voltage of the bridge arm module 3 are obtained based on each switch control sequence, and whether the circuit is faulty is determined based on the battery voltage, the first output voltage, the second output voltage and a preset voltage threshold, including:

[0118] Under a first control sequence, collecting a first output voltage of the resistor network module 2 and a second output voltage of the bridge arm module 3; calculating a first voltage value based on the first output voltage and the second output voltage, and calculating a second voltage value 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, the circuit is faulty;

[0119] Under the second control sequence, a second output voltage of the bridge arm module 3 is collected; a third voltage value is calculated based on the second output voltage, and if the third voltage value is not equal to the battery voltage, a circuit fault occurs;

[0120] Under the third control sequence, the second output voltage of the bridge arm module 3 is collected; a fourth voltage value is calculated based on the second output voltage, and if the fourth voltage value is not equal to the battery voltage, the circuit fails.

[0121] In this embodiment, several control sequences are preset, and the control sequences include on-control and off-control of different switches, so as to adjust the flow of current in the circuit.

[0122] Please refer to Figure 2 , Figure 2 A connection diagram of a defect detection circuit provided by an embodiment of the present invention.

[0123] In this embodiment, the switch elements in the defect detection circuit are controlled by a first control sequence, wherein the first switch element 5 , the second switch element 6 and the third switch element 7 are all in the off state.

[0124] In this embodiment, since the first switching element 5 is disconnected, the resistance network module 2 and the resistance 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, the circuit fails.

[0125] In this embodiment, the first voltage value V 1 Specifically:

[0126] V 1 =V p +V n (1)

[0127] In this embodiment, V n is based on the first output voltage V of the resistor network module 2 x Calculated, V p is based on the second output voltage V of the bridge arm module 3 y Calculate, specifically:

[0128] V p =V y ·n (2)

[0129] V n =V x ·n (3)

[0130]

[0131] Among them, R 1 is the resistance value of the first resistor 21, R 2is the resistance value of the second resistor 22.

[0132] In this embodiment, the second voltage value V 2 Based on the resistance value R of the fifth resistor 31 5 , the resistance value of the sixth resistor 32 is R 6 , the seventh resistor 33R 7 And the second output voltage V y Calculate, specifically:

[0133]

[0134] In this embodiment, when the second switch element 6 and the third switch element 7 are both disconnected, if the first switch element 5 is closed, the first voltage value V 1 Should be equal to the battery voltage V B If they are equal, then V B =V p +V n If the first switch element 5 is disconnected, only When V B =V p +V n , where R P is the resistance value of the first equivalent resistor 11, R n is the resistance value of the second equivalent resistor 12. Therefore, when V B ≠V p +V n When the first switch element 5 is disconnected, it can be confirmed that the first switch element 5 is disconnected. Then the voltage dividing module 4 in the circuit, that is, the switching circuit of the second switching element 6 and the third switching element 7 is faulty.

[0135] In this embodiment, please refer to Figure 3 , Figure 3 Another connection diagram of a defect detection circuit provided by an embodiment of the present invention.

[0136] In this embodiment, the switch elements in the defect detection circuit are controlled by the second control sequence, wherein the first switch element 5 and the second switch element 6 are in the disconnected state, and the third switch element 7 is in the on state.

[0137] In this embodiment, since the first switch element 5 is disconnected, the resistance network module 2 and the resistance 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, and if the third voltage value is not equal to the battery voltage, the circuit fails.

[0138] In this embodiment, the third voltage value V 3The calculation is based on the second output voltage, the third resistor 41, the fifth resistor 31, the sixth resistor 32 and the seventh resistor 33. Specifically:

[0139]

[0140] In this embodiment, if Then the control circuit of the third switching element 7 fails.

[0141] Please refer to Figure 4 , Figure 4 Another connection diagram of a defect detection circuit provided by an embodiment of the present invention.

[0142] In this embodiment, the switch elements in the defect detection circuit are controlled by the second control sequence, wherein the first switch element 5 and the third switch element 7 are in the off state, and the second switch element 6 is in the on state.

[0143] In this embodiment, since the first switch element 5 is disconnected, the resistance network module 2 and the resistance 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, and if the fourth voltage value is not equal to the battery voltage, the circuit fails.

[0144] 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:

[0145]

[0146] In this embodiment, if Then the control circuit of the second switching element 6 fails.

[0147] In this embodiment, by controlling the on-state and closed-state of each switch element in the circuit and switching the circuit connectivity state, the output voltage of the resistor network module 2 and the bridge arm module 3 is detected, and based on the output voltage set collected under different connectivity states, whether the switch elements and each loop in the detection circuit are faulty is detected, thereby performing a comprehensive detection of the insulation detection circuit to prevent circuit component failures from affecting the accuracy of insulation detection.

[0148] Please refer to Figure 5 and Figure 6 , Figure 5 A schematic diagram of a defect detection circuit provided by an embodiment of the present invention is provided. Figure 6 A schematic flow chart of a defect detection method provided by an embodiment of the present invention.

[0149] In this embodiment, a defect detection circuit includes: an equivalent insulation module 1, a resistance network module 2, a bridge arm module 3, a voltage divider module 4, a first switch element 5, a second switch element 6, a third switch element 7 and a fourth switch element 8;

[0150] The first end of the equivalent insulation module 1 is electrically connected to the first end of the resistance network module 2, the third switch 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 second switch 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 switch element 5, the resistance network module 2 and the ground wire;

[0151] 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 end of the power module 13, the first end of the first resistor 21, the first end of the bridge arm module 3 and the third switch element 7; 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 electrically connected to the second end of the second resistor 22, the ground wire and the first switch element 5; the second end of the second equivalent resistor 12 is electrically connected to the negative end of the power module 13, the second end of the bridge arm module 3 and the second switch element 6; the positive end of the power module 13 is electrically connected to the first end of the first resistor 21, the first end of the bridge arm module 3 and the third switch element 7; the negative end of the power module 13 is electrically connected to the second switch element 6 and the bridge arm module 3.

[0152] 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 electrically connected to the first end of the equivalent insulation module 1, the third switch element 7 and the first end of the bridge arm module 3; 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 first end of the second resistor 22 is electrically connected to the first voltage detection module 23; the second end of the second resistor 22 is electrically connected to the third end of the equivalent insulation module 1, the first switch element 5 and the ground wire.

[0153] The voltage divider module 4 includes: a third resistor 41 and a fourth resistor 42; the first end of the third resistor 41 is electrically connected to the third switch element 7; the second end of the third resistor 41 is electrically connected to the first switch element 5 and the third end of the bridge arm module 3; the second end of the third resistor 41 is electrically connected to the first end of the fourth resistor 42; the first end of the fourth resistor 42 is electrically connected to the first switch element 5; the first end of the fourth resistor 42 is electrically connected to the third end of the bridge arm module 3; the second end of the fourth resistor 42 is electrically connected to the second switch element 6.

[0154] 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 electrically connected to the third switch element 7, the first end of the first resistor 21, the first end of the first equivalent resistor 11 and the positive end of the power module 13; the second end of the fifth resistor 31 is electrically connected to the first end of the sixth resistor 32; the second end of the fifth resistor 31 is electrically connected to the second end of the third resistor 41, the first end of the fourth resistor 42 and the first switch element 5; the first end of the sixth resistor 32 is electrically connected to the second end of the third resistor 41, the first end of the fourth resistor 42 and the first switch element 5; 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 electrically connected to the second voltage detection module 34; the first end of the seventh resistor 33 is electrically connected to the second voltage detection module 34; the second end of the seventh resistor 33 is electrically connected to the second switch element 6, the second end of the second equivalent resistor 12 and the positive end of the power module 13.

[0155] The first end of the fourth switch element 8 is electrically connected to the first end of the first equivalent resistor 11, the positive terminal of the power module 13, the third switch element 7 and the first end of the fifth resistor 31; the first end of the fourth switch element 8 is electrically connected to the first end of the first resistor 21.

[0156] In this embodiment, when the defect detection is performed based on the defect detection circuit, the fourth switch element 8 (S1) is first closed, and the first switch element 5 (SG), the second switch element 6 (S2) and the third switch element 7 (S3) are opened. At this time, V is calculated based on the first output voltage. n , calculate V based on the second output voltage p , and determine V p +V n Is it equal to the battery voltage V B .

[0157] If V B =V p +V n , then calculate the second voltage value V 2 , if the second voltage value V 2 Equal to the battery voltage V B , then close the third switch element 7 and calculate the third voltage value V 3 and the fifth voltage value V 5 , compare the third voltage value V 3 and the fifth voltage value V 5 , when V B ≠V p +V n , and V 3 =V 5 , then the third switch element 7 is turned off and the second switch element 6 is turned on, otherwise the circuit fails, wherein,

[0158] If V B ≠V p +V n , the first switch element 5 is disconnected, and the second voltage value V is calculated at this time. 2 , if the second voltage value V 2 Equal to the battery voltage V B , then close the third switch element 7 and calculate the third voltage value V 3 and the fifth voltage value V 5 , compare the third voltage value V 3 and the fifth voltage value V 5 , when V B ≠V p +V n , and V 3 =V 5 , then the third switch element 7 is turned off and the second switch element 6 is turned on, otherwise the circuit fails, wherein,

[0159] When the third switch element 7 is turned off and the second switch element 6 is turned on, the fifth voltage value V is calculated. 5 and the fourth voltage value V 4 , when the fifth voltage value V 5 and the fourth voltage value V 4 Equal, that is When the first switch element 5 is closed, V is calculated again. p and V n , and determine V p +V n Is equal to the battery voltage if and only if V p +V n =V B When the circuit self-check is normal.

[0160] In this embodiment, by controlling the on-state and closed-state of each switch element in the circuit and switching the circuit connectivity state, the output voltage of the resistor network module 2 and the bridge arm module 3 is detected, and based on the output voltage set collected under different connectivity states, whether the switch elements and each loop in the detection circuit are faulty is detected, thereby performing a comprehensive detection of the insulation detection circuit to prevent circuit component failures from affecting the accuracy of insulation detection.

[0161] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A defect detection circuit, characterized in that: include: An equivalent insulation module (1), a resistance network module (2), a bridge arm module (3), a voltage divider module (4), a first switch element (5), a second switch element (6) and a third switch element (7); The first end of the equivalent insulation module (1) is electrically connected to the first end of the resistance network module (2), the third switch 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 second switch 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 switch element (5), the resistance network module (2) and the ground wire; The first end of the resistance network module (2) is electrically connected to the third switch element (7) and the first end of the bridge arm module (3) respectively; the second end of the resistance network module (2) is electrically connected to the ground line and the first switch element (5); The first end of the voltage dividing module (4) is electrically connected to the third switch element (7); the second end of the voltage dividing module (4) is electrically connected to the second switch element (6); the third end of the voltage dividing module (4) is electrically connected to the first switch element (5) and the third end of the bridge arm module (3); The first end of the bridge arm module (3) is electrically connected to the third switch element (7); and the second end of the bridge arm module (3) is electrically connected to the second switch element (6).

2. A defect detection circuit as claimed in claim 1, characterized in that: The resistor network module (2) comprises a first resistor (21), a second resistor (22) and a first voltage detection module (23); The first end of the first resistor (21) is electrically connected to the first end of the equivalent insulation module (1), the third switch element (7) and the first end of the bridge arm module (3); 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 first end of the second resistor (22) is electrically connected to the first voltage detection module (23); The second end of the second resistor (22) is electrically connected to the third end of the equivalent insulation module (1), the first switch element (5) and the ground wire.

3. A defect detection circuit as claimed in claim 2, characterized in that: The equivalent insulation module (1) comprises 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), the first end of the first resistor (21), the first end of the bridge arm module (3) and the third switch element (7); 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 electrically connected to the second end of the second resistor (22), the ground line and the first switch element (5); The second end of the second equivalent resistor (12) is electrically connected to the negative terminal of the power module (13), the second end of the corresponding bridge arm module (3) and the second switch element (6); The positive terminal of the power module (13) is electrically connected to the first end of the first resistor (21), the first end of the bridge arm module (3) and the third switch element (7); The negative terminal of the power module (13) is electrically connected to the second switch element (6) and the bridge arm module (3).

4. A defect detection circuit as claimed in claim 3, characterized in that: The voltage dividing module (4) comprises: a third resistor (41) and a fourth resistor (42); The first end of the third resistor (41) is electrically connected to the third switch element (7); The second end of the third resistor is electrically connected to the first switch element (5) and the third end of the bridge arm module (3); the second end of the third resistor (41) is electrically connected to the first end of the fourth resistor (42); The first end of the fourth resistor (42) is electrically connected to the first switch element (5); the first end of the fourth resistor (42) is electrically connected to the third end of the bridge arm module (3); The second end of the fourth resistor (42) is electrically connected to the second switch element (6).

5. A defect detection circuit as claimed in claim 4, characterized in that: The bridge arm module (3) comprises 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 electrically connected to the third switch element (7), the first end of the first resistor (21), the first end of the first equivalent resistor (11) and the positive terminal of the power module (13); The second end of the fifth resistor (31) is electrically connected to the first end of the sixth resistor (32); the second end of the fifth resistor (31) is electrically connected to the second end of the third resistor (41), the first end of the fourth resistor (42) and the first switch element (5); The first end of the sixth resistor (32) is electrically connected to the second end of the third resistor (41), the first end of the fourth resistor (42) and the first switch element (5); 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 electrically connected to the second voltage detection module; The first end of the seventh resistor (33) is electrically connected to the second voltage detection module (34); The second end of the seventh resistor (33) is electrically connected to the second switch element (6), the second end of the second equivalent resistor (12) and the positive terminal of the power module (13).

6. A defect detection circuit as claimed in claim 1, characterized in that: The defect detection circuit further comprises a fourth switch element (8); The first end of the fourth switch element (8) is electrically connected to the first end of the equivalent insulation module (1), the third switch element (7) and the first end of the bridge arm module (3); the second end of the fourth switch element (8) is electrically connected to the first end of the resistance network module (2).

7. A defect detection circuit according to any one of claims 1 to 6, characterized in that: The first end of the fourth switch element (8) is electrically connected to the first end of the first equivalent resistor (11), the positive terminal of the power module, the third switch element (7) and the first end of the fifth resistor (31); the first end of the fourth switch element (8) is electrically connected to the first end of the first resistor (21).

8. A defect detection method, characterized in that: A defect detection circuit as claimed in any one of claims 1 to 7, comprising: Controlling the on state and the closed state of the first switch element, the second switch element, and the third switch element based on a preset switch control sequence set; The first output voltage of the resistor network module and the second output voltage of the bridge arm module are obtained based on each switch control sequence, and whether the circuit is faulty is determined based on the battery voltage, the first output voltage, the second output voltage and a preset voltage threshold.

9. A defect detection method according to claim 8, characterized in that: 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 switch element, the second switch element and the third switch element being all in an off state; The second control sequence includes the first switch element and the second switch element being in an off state, and the third switch element being in an on state; The third control sequence includes the first switch element and the third switch element being in an off state, and the second switch element being in an on state.

10. A defect detection method according to claim 9, characterized in that: The method of acquiring the first output voltage of the resistor network module and the second output voltage of the bridge arm module based on each switch control sequence, and judging 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 first control sequence, collecting the first output voltage of the resistor network module and the second output voltage of the bridge arm module; calculating a first voltage value based on the first output voltage and the second output voltage, and calculating a second voltage value 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 fails; collecting the second output voltage of the bridge arm module under the second control sequence; calculating a third voltage value based on the second output voltage, and if the third voltage value is not equal to the battery voltage, a circuit fault occurs; The second output voltage of the bridge arm module is collected under the third control sequence; a fourth voltage value is calculated based on the second output voltage, and if the fourth voltage value is not equal to the battery voltage, a circuit fault occurs.

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