Method and system for detecting high-voltage circuit of electric vehicle

Abstract

The invention relates to the technical field of electric vehicle high-voltage circuit detection, in particular to an electric vehicle high-voltage circuit detection method and system. The method comprises the following steps: acquiring a working mode of a vehicle, and determining a high-voltage loop related to the working mode as a detection loop; before high voltage is applied to the detection loop, cable installation state detection is carried out on a connection part on the detection loop, and real conductivity detection is carried out on the detection loop; after high voltage is applied to the detection loop, real-time conductivity detection is carried out on the detection loop; according to the results of the cable installation state detection, the real conductivity detection and the real-time conductivity detection, whether a fault exists in the detection loop is determined; if the fault exists, determining the fault level according to the occurrence position of the fault and the working mode look-up table; and according to the fault level, determining a fault processing strategy in the current working mode so as to perform targeted processing, thereby reducing the influence on the vehicle operation performance on the premise of ensuring the vehicle safety.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle high-voltage circuit detection, and particularly relates to a method and system for detecting an electric vehicle high-voltage circuit. Background Art

[0002] The existing technology for detecting the connection state of high-voltage cables mainly focuses on the detection of the connection state of quick-connect plug-in connection state detection terminals, and performs state equivalent substitution after detecting conduction, and optimizes and expands the detection method for the loop formed by interlock terminals, which is divided into series, parallel, voltage signal, PWM pulse signal, constant current signal, AD module conversion, etc. For the detection components, simple partition detection and corresponding strategy processing are also carried out, as well as the expansion and combination of parallel resistors to subdivide the detection points and detection equipment.

[0003] However, the existing technology often only performs low-voltage loop integrity substitution detection on quick-connect high-voltage plugs with interlock detection pins, lacking a more detailed and effective fault discrimination processing flow, and having insufficient accurate judgment and recognition ability for abnormal detection points, which is not conducive to accurately locating faults for targeted processing. Due to limited detection methods, the existing technology usually has difficulty in accurately locating the occurrence position of faults. To ensure safety, all faults that occur are uniformly reported as high-level fault alarms, which is not conducive to the vehicle maintaining driving and use to the greatest extent in different working modes. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and system for detecting an electric vehicle high-voltage circuit. The present invention performs cable installation state detection and real conduction detection on the connection components before power-on, and performs real-time conduction monitoring after power-on, which can more completely cover potential fault points on the high-voltage loop that may affect loop conduction. At the same time, the entire high-voltage loop is comprehensively detected to detect faults and determine the fault occurrence position. Subsequently, according to the fault occurrence position, the fault level of the fault can be determined by looking up a table to select a corresponding processing strategy. Such a hierarchical processing method can, on the basis of comprehensive detection, ensure safety as much as possible without affecting the operation performance of the vehicle itself.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions to solve: In the first aspect, the present invention provides a method for detecting the integrity of a high-voltage circuit, which includes: Obtain the working mode of the vehicle, and determine the high-voltage loop related to the working mode as the detection loop; Before applying high voltage to the detection loop, perform cable installation state detection on the connection parts of the detection loop and perform real conduction detection on the detection loop; After applying high voltage to the detection loop, perform real-time conduction detection on the detection loop; Determine whether there is a fault in the detection loop according to the results of the cable installation state detection, true conductivity detection, and real-time conductivity detection; If there is a fault, look up the fault level in a table according to the location of the fault and the working mode; determine the fault handling strategy according to the fault level.

[0006] Optionally, when the connection part is connected by a quick plug-in, the cable installation state detection of the connection part on the detection loop includes: If the quick plug-in has an interlock pin, connect the interlock pin to the high-voltage detection controller to determine the connection locking state of the quick plug-in. If the connection locking state is abnormal, it is determined that there is a fault with the quick plug-in; If the quick plug-in does not have an interlock pin, use the spare signal line pin to replace the interlock pin and connect it to the high-voltage detection controller to determine the connection locking state of the quick plug-in. If the connection locking state is abnormal, it is determined that there is a fault with the quick plug-in.

[0007] Optionally, when the connection part is connected by a gland, the cable installation state detection of the connection part on the detection loop includes: Install a cable position detection sensor in the junction box of the gland in advance; Use the cable position detection sensor to detect the real-time position of the cable installed in the junction box. If the real-time position of the cable is abnormal, it is determined that there is a fault with the gland.

[0008] Optionally, the cable position detection sensor includes: A base, installed at the cover plate of the junction box; A flap, movably installed at the cover plate of the junction box; A shrapnel and a metal shorting piece, respectively installed on the base or the flap; After the cable is installed in place in the junction box, it can contact the flap, so that the shrapnel contacts the metal shorting piece to connect the loop. If the loop is disconnected, it means that the real-time position of the cable is abnormal.

[0009] Optionally, the cable position detection sensor includes: A base, provided in the junction box, and the base is provided with a contact; A movable shorting piece, provided in the junction box, and a first spring is provided between the movable shorting piece and the junction box; A telescopic compensation rod, provided on the movable shorting piece and used to contact the cable, and a second spring is provided between the telescopic compensation rod and the movable shorting piece, and the elastic coefficient of the second spring is greater than that of the first spring; After the cable is installed in place in the junction box, it can compress the first spring and the second spring through the telescopic compensating rod. The first spring is compressed first so that the movable short-circuit piece contacts the contact to connect the circuit. If the circuit is disconnected, it indicates that the real-time position of the cable is abnormal.

[0010] Optionally, the detection method further includes: Before applying high voltage to the detection circuit, detect the non-quick-release type MSD; Detect the real-time position of the high-voltage fuse body in the MSD through a cable position detection sensor pre-installed in the MSD; If the real-time position of the high-voltage fuse body is abnormal, it is determined that the non-quick-release type MSD has a fault.

[0011] Optionally, the real conduction detection includes: Inject a pulse detection signal into the detection circuit, If all detection points on the detection circuit correctly receive the pulse detection signal, it indicates that the detection circuit is conducting; If the detection circuit is not conducting, find the first detection point that fails to correctly receive the pulse detection signal along the signal propagation direction as the location where the fault occurs.

[0012] Optionally, the real-time conduction detection of the detection circuit includes: Obtain the real-time voltage or real-time current of the detection points pre-arranged on the detection circuit; Regard the detection points where the real-time voltage or real-time current does not conform to the preset normal value as the fault points to determine the location where the fault occurs.

[0013] Optionally, the determining the fault handling strategy in the current working mode according to the fault level includes: The fault level is divided into first level, second level and third level; If the fault level is the first level, only give a warning; If the fault level is the second level, limit the output power in the current working mode of the vehicle and give a warning; If the fault level is the third level, terminate the output of the current working mode of the vehicle, stop and cut off the high voltage.

[0014] In a second aspect, the present invention provides an electric vehicle high-voltage circuit detection system, which includes: A determination module, configured to obtain the working mode of the vehicle and determine the high-voltage circuit related to the working mode as the detection circuit; A test mode is used to detect the cable installation status of the connection parts on the detection loop and perform a real conduction test on the detection loop before applying high voltage to the detection loop; after applying high voltage to the detection loop, perform a real-time conduction test on the detection loop; A fault determination module is used to determine whether there is a fault in the detection loop according to the results of the cable installation status detection, real conduction test, and real-time conduction test; A processing module is used to, if a fault exists, look up the fault level according to the location of the fault and the working mode in a table; determine a fault handling strategy according to the fault level.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention first determines the high-voltage loop to be detected as the detection loop according to the vehicle working mode to save detection resources and enhance pertinence. Subsequently, the cable installation status of the connection parts of the determined detection loop is detected. This alternative detection of non-conduction monitoring can pre-detect faults before power-on, and the present invention can include both connection components with interlock pins and those without interlock pins within the detection range to facilitate accurately determining the fault location and subsequent targeted fault handling. In addition to the cable installation status detection, the present invention also performs a real conduction test before power-on and a real-time conduction test after power-on, so as to cooperate with the cable installation status detection to achieve comprehensive detection to accurately determine the location of the fault. After obtaining the location of the fault, look up the fault level in a pre-acquired fault level table, and perform targeted fault handling according to the fault level to achieve refined fault handling, thereby minimizing the impact on the vehicle running performance as much as possible while ensuring vehicle safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic flow chart of the high-voltage circuit integrity detection method in Embodiment 1; Figure 2 It is a demonstration schematic diagram of the cable position detection sensor with a flip-type elastic sheet structure installed in the gland terminal box in Embodiment 1, at this time the cable is not installed in place yet; Figure 3 For Figure 2 When the cable in is installed in place, it is a schematic structural diagram of the upper and lower installations of the cable position detection sensor installed in the gland terminal box; Figure 4 It is a schematic diagram of the upper and lower installations of the cable position detection sensor with a flip-type Hall detection structure installed in the gland terminal box in Embodiment 1; Figure 5 It is a schematic diagram of the upper and lower installations of the cable position detection sensor with a telescopic contact type in the gland terminal box in Embodiment 1; Figure 6 Schematic diagram of the installation of the proximity cable position detection sensor in the gland junction box in Embodiment 1; Figure 7 Schematic diagram of the installation of the non - quick - plug MSD fuse internal installation position detection sensor in Embodiment 1; Figure 8 Schematic diagram of the equivalent circuit of the battery heating film for real - time conductivity detection in Embodiment 1; Figure 9 Schematic diagram of the conduction detection of the battery heating high - voltage circuit in Embodiment 1; Figure 10 Schematic diagram of the five - wire conduction detection of the permanent magnet motor for real - time conductivity detection in Embodiment 1. Detailed implementation manners

[0017] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more. In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0018] The present invention will be further described below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention. Embodiment

[0019] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0020] Combined with Figure 1 , this embodiment provides a high-voltage circuit integrity detection method, which includes: Step S1, obtain the working mode of the vehicle, and determine the high-voltage circuit related to the working mode as the detection circuit; The purpose of obtaining the working mode of the vehicle in this embodiment is to determine the detection range to save detection resources. At the same time, according to the working mode of the vehicle, it is also beneficial to perform targeted processing on faults, reduce the excessive impact on irrelevant components of the vehicle, and thus ensure the normal use of the vehicle and the safe operation of the current mode as much as possible.

[0021] In some specific embodiments, the working modes of the vehicle include a maintenance mode, a charging mode, a power replenishment mode, and a discharging mode.

[0022] The maintenance mode is determined when the vehicle is not powered on with high voltage and the quick-release MSD (Maintenance Switch Disconnector) at the PDU (Power Distribution Unit) and / or BDU (Battery Drive Unit) is removed. In this mode, the vehicle is not in a working state, and the detection process will not affect the use of the vehicle. All high-voltage circuits are detected, and the detection results are reported to facilitate maintenance personnel to understand the vehicle condition.

[0023] The charging mode is determined according to the charging connection signal and the charging status signal sent by the battery management system BMS. Here, the charging mode can be the vehicle-mounted charging of the battery, the off-vehicle charging of the battery of the battery-swapping vehicle separately in the station, or the off-vehicle charging of the battery itself independently. In the charging mode, the charging circuit and the high-voltage circuits related to the charging function and carrying high voltage need to be detected as the detection circuits. When a fault occurs during the detection, early warning and targeted processing are required. In some specific embodiments, the targeted processing here can be to limit the charging power or terminate the charging.

[0024] The power replenishment mode means that when the vehicle is in the ON power (ignition lock ignition trigger) or the off-power state but the constant power supply is not interrupted, when the low-voltage battery power is lower than the safety threshold for power replenishment, the high-voltage power supply circuit required for power replenishment is closed and the DCDC module is enabled to enter the power replenishment mode. In the power replenishment mode, the high-voltage circuits related to power replenishment and carrying high voltage need to be detected as the detection circuits. When a fault occurs during the detection, early warning and targeted processing are required. The targeted processing here can be to limit the power replenishment power or terminate the power replenishment.

[0025] The discharge mode indicates that the vehicle is in a state where high voltage has been applied and is either stationary or in operation. At this time, the circuits and devices independently related to charging will not be energized or function due to the charging and discharging function interlock. Therefore, the detection, monitoring, and alarm of the circuits and devices related to charging can cancel the detection or reduce the detection frequency as needed. The key is to detect the high-voltage circuits and related devices related to vehicle driving discharge. When a fault is detected during the detection, a warning needs to be given and targeted handling is required. The targeted handling here can be to limit the discharge power or terminate the discharge. In addition, although the energy recovery in the discharge form is a charging process for the battery, it actually occurs during the vehicle driving discharge process, so it is not included in the charging mode and is executed according to the monitoring and detection strategy of the discharge mode.

[0026] Step S2: Before the detection circuit is energized with high voltage, perform cable installation state detection on the connection parts of the detection circuit and real conduction detection on the high-voltage circuit; after the detection circuit is energized with high voltage, perform real-time conduction detection on the detection circuit. It can be understood that compared with the single detection method in the traditional technology that only performs low-voltage circuit integrity alternative detection on the fast plug-in with interlock detection pins, the detection method adopted in this embodiment belongs to the comprehensive detection carried out in cooperation with cable installation state detection (not directly detecting the conduction state of the circuit, actually belonging to alternative judgment detection), real conduction detection (conduction detection before high voltage is applied), and real-time conduction detection (conduction detection after high voltage is applied). The coverage range is wider, the fault detection rate is high, and the location of the fault point is determined more accurately. The determination of the fault occurrence time and the working mode of the vehicle's corresponding high-voltage system and the subsequent determination of the fault level and the formulation of the fault handling strategy are also more accurate.

[0027] Step S2.1: Before the detection circuit is energized with high voltage (when receiving the high-voltage application command when the power is turned on), perform cable installation state detection on the connection parts of the detection circuit; when the connection parts are connected by fast plug-ins, the cable installation state detection on the connection parts of the detection circuit includes: if the fast plug-in has an interlock pin, connect the interlock pin to the high-voltage detection controller to determine the connection locking state of the fast plug-in, and also realize real-time monitoring and one-to-one identification of the connection locking state of the fast plug-in. If the connection locking state is abnormal, it is determined that the fast plug-in has a fault; if the fast plug-in does not have an interlock pin, use the spare signal line pin to replace the interlock pin and connect it to the high-voltage detection controller to build a circuit, so as to determine the connection locking state of the fast plug-in. If the connection locking state is abnormal, it is determined that the fast plug-in has a fault.

[0028] In addition, in practice, not all connection parts adopt quick connectors. For example, components such as the main positive and negative lines of the battery, the main positive and negative lines of the drive motor controller (MCU) and its three-phase lines of the drive motor, and the battery charging line have high power and large current, and the cable diameter is relatively thick. If quick connectors of the corresponding grade are used, the cost is relatively high, and the current-carrying capacity is relatively low compared to bolt fixation. Therefore, for reasons such as vehicle cost control, gland-type waterproof fixation is often adopted. However, the gland lacks interlock pins for direct connection detection, and it is also impossible to rely on the existing structure of the gland itself to achieve the detection of the effectiveness of cable connection. As a result, in the prior art, the coverage of interlock pin detection is insufficient, and it is mainly concentrated on the high-voltage power distribution controller side that mostly uses quick connectors, lacking detection coverage conditions for the electrical appliance side and the battery side with more glands. The detection range is limited and there are detection blind spots, the fault detection rate is low, and the difficulty of fault troubleshooting is large.

[0029] The detection method of the present embodiment covers the gland. Specifically, to address the drawback that the gland cannot determine the plug connection state through the interlock pins, the present embodiment is implemented by installing a cable position detection sensor inside the gland junction box. The cable position detection sensor is used to detect the real-time position of the cable installed in the junction box. If the real-time position of the cable is abnormal, it is determined that there is a fault in the gland.

[0030] The cable position detection sensor in this embodiment adopts two major categories in terms of structural form: contact detection and non-contact detection. Among them, contact detection adopts two structures: the flap type and the telescopic type, and non-contact detection adopts three structures: the Hall magnetic induction type, the proximity type, and the ranging type. In terms of the detection principle adopted by the cable position detection sensor, there are five relatively low-cost, stable and reliable detection methods: the elastic sheet contact method, the Hall magnetic induction method, the telescopic contact point method, the proximity method, and the ranging method. Among them, the ranging method can specifically adopt specific implementation methods such as laser ranging, photoelectric gate induction, and ultrasonic ranging. In terms of the installation position of the cable position detection sensor, the cable position detection sensor can be installed above or below the cable. Among them, most of the cable position detection sensors are fixed on the inner side of the junction box cover, with a small amount of modification and easy to implement, low modification cost, and having the additional effect of open cover detection. The cable position detection sensor needs to send data out through leads. In terms of the lead-out method, it can be divided into three methods: waterproof lead-out from the top of the cover, waterproof lead-out from the side of the junction box, and lead-in to the device from the bottom of the junction box. The first two are suitable for the application scenarios where the leads are externally led to a high-voltage detection controller elsewhere or enter the device uniformly through a low-voltage plug outside the device. The third is suitable for the situation where there is a controller inside the device that can detect this signal or there is a high-voltage detection controller, so that it can directly enter the device for wiring. In terms of the installation position, it is divided into two major categories: fixed detection inside the upper cable maintenance cover and fixed detection inside the lower cable junction box. Among them, it is relatively easy to fix on the inner side of the maintenance cover. Generally speaking, the amount of modification is small and easy to implement, the modification cost is low, and it has the additional effect of open cover detection. The above various classification methods can be selected and determined according to actual needs.

[0031] In a specific embodiment, the cable position detection sensor includes a base, a flap, an elastic sheet, and a metal short-circuit sheet. The elastic sheet and the metal short-circuit sheet are respectively installed on the base or the flap. After the cable is installed in place in the junction box, it can contact the flap, so that the elastic sheet contacts the metal short-circuit sheet to connect the circuit. If the circuit is disconnected, it indicates that the real-time position of the cable is abnormal. This will be described in combination with a specific example. Combining Figure 2 , this figure shows an installation schematic diagram of arranging the cable position detection sensor 8 with a flap type structure above and below the cable in the junction box (at this time, the junction box cover 7 and the cable have not been installed in place yet), and the adopted detection principle is that the elastic sheet is pressed to conduct. Figure 2The cable therein includes the outer insulating skin 1 of the high-voltage cable, the inner insulating skin 2 exposed after stripping the outer insulating skin at the front end of the high-voltage cable (the shielding layer metal mesh is between the outer insulating skin and the inner insulating skin, and the stripping is to expose the shielding layer for facilitating contact with the shielding grounding structure of the gland to achieve cable shielding), and the OT copper terminal 3 crimped at the exposed copper wire at the front end of the high-voltage cable; the gland includes the gland waterproof joint assembly 4, the cable position detection sensor 8 includes the lead wire 5 led out from the cover plate, and the cover plate is also provided with the cable waterproof part 6 for the lead wire 5 to lead out. The base of the cable position detection sensor 8 is fixed on the cover plate, and highly elastic metal contact spring pieces are arranged on the side of the base; the flap 9 of the cable position detection sensor 8 is movably installed on the base of the cable position detection sensor, Figure 2 The shown flap 9 is a rocker arm (with a metal short-circuit piece, and shown as the maximum opening angle position when not installed in place or without a cable), and the contact surface of the flap for contacting the cable has an arc-shaped protrusion, so as to effectively avoid the interference of the cable base surface when the flap contacts the cable, and also avoid the interference and jamming of the flap with other objects during rotation. The high-voltage copper busbar 10 in the junction box, the copper busbar through hole 11, the copper busbar insulation mounting base 12, the fixing bolt 13 for the copper busbar and the high-voltage cable OT terminal at the bottom of the junction box, and the installation position of the bottom wire passing hole of the detector cable installed in the lower position (since it is inside the waterproof junction box, if there is no requirement for sealing, waterproofing and dustproofing for the space of the junction box inside the equipment at this place, it can not be sealed) 14 is as Figure 2 shown, in addition, the cable position detection sensor 8 can also be installed on the lower side of the cable, and the installation position 15 of the cable position detection sensor 8 installed on the lower side (installed in the lower position) of the cable is as Figure 2 shown. The flap and the base of the cable position detection sensor 8 are both made of insulating materials, and can withstand the voltage value of the high-voltage system without short-circuit breakdown or causing insulation problems in the vehicle's high-voltage system. There is a torsion spring at the installation rotating shaft of the flap, which gives the flap an upward force. After the cable is installed in place, pressing the flap flat can realize induction to provide signals or reliable contact of the spring pieces to connect the circuit. The sizes of the components of the flap are small and convenient for installation in the narrow space of the gland junction box, but for clear illustration, the sizes of the components shown in the figure are all enlarged and not the real size ratio and specific shape.

[0032] Figure 3 Figure 10 shows the schematic diagrams of the upper-position installation (installed on the upper side of the cable) and the lower-position installation (installed on the lower side of the cable) of the cable position detection sensor with a flap structure in the junction box when the cable and the junction box cover plate have been installed in place.

[0033] Figure 4 Figure 14 shows the schematic diagrams of the upper-position installation and the lower-position installation of the cable position detection sensor in the gland junction box when using the flap-type Hall detection structure for detection, Figure 4The detection principle adopted by the cable position detection sensor therein is the Hall magnetic induction method. A Hall sensor is arranged on the base of the cable position detection sensor, and a magnet for sensing is provided on the flap. The upward lifting angle range of the flap is limited in advance. It is necessary to ensure normal induction between the Hall sensor and the magnet (to avoid misjudgment due to overly sensitive induction and ensure reliable signal break for accurate state judgment), while preventing the flap from opening and closing too much and interfering with the cable.

[0034] Figure 5 Schematic diagrams of the upper and lower installations of the telescopic contact type cable position detection sensor in the gland junction box Figure 5 The detection principle adopted by the cable position detection sensor is the telescopic contact type. In this method, the base of the cable position detection sensor is arranged in the junction box. A contact is provided on the base of the cable position detection sensor. An active short-circuit piece 21 is also provided in the junction box. A first spring is provided between the active short-circuit piece 21 and the junction box; A telescopic compensation rod 22 for contacting the cable is provided on the active short-circuit piece 21; A second spring is provided between the telescopic compensation rod 22 and the active short-circuit piece 21, and the elastic coefficient of the second spring is greater than that of the first spring; After the cable is installed in place in the junction box, the first spring and the second spring can be compressed through the telescopic compensation rod 22. The first spring is compressed first to make the active short-circuit piece 21 contact and connect the circuit with the contact. If the circuit is disconnected, it indicates that the real-time position of the cable is abnormal. In actual use, under the pressure of the cable, the distance between the active short-circuit piece 21 and the two terminals is first completely compressed and contacted with each other, and then the telescopic compensation rod 22 is continuously compressed. Relying on the pressure of the first spring to resist the elastic force of the second spring, the active short-circuit piece is further pressed to keep the active short-circuit piece in effective contact with the contact on the base; At the same time, relying on the compression effect of the second spring can compensate the stroke and be compatible with the assembly clearance error. Similarly, the pairing combination of the active short-circuit piece and the contact in the telescopic contact type cable position detection sensor can also be changed to the pairing combination of the magnet and the Hall. The Hall replaces the contact on the base, and the magnet is placed at the position of the active short-circuit piece to achieve the same function.

[0035] Figure 6 Schematic diagram of the installation of the proximity type cable position detection sensor in the junction box. The proximity type cable position detection sensor includes a Hall detection end, and one end of the Hall detection end is fixedly connected to the cable installed in the junction box to detect the real-time position of the cable. The Hall detection end can be firmly fixed by various types of adhesive glue, heat shrinkable tube, waterproof tape, etc., to ensure that the Hall detection end can effectively detect the presence of the cable, and the structure is simpler, more reliable and easier to implement.

[0036] In addition to the quick-plug and cable gland, this embodiment can also detect non-quick-release MSD (Maintenance Switch Disconnector) without interlocking pins. The high-voltage fuse inside the non-quick-release MSD is fixed to the base copper busbar by bolts on both sides of the copper busbar, which cannot be quickly disassembled. The external protective cover must be removed in advance for disassembly. This type of MSD has a relatively low cost and obvious cost reduction effect. It is often installed on a battery box MSD with a large number but a low probability of disassembly. However, the battery box is also one of the components of the high-voltage circuit. Once it is disassembled or an interlocking problem occurs, it is often more difficult to troubleshoot due to the large number and position. Therefore, it is also necessary to cover the interlocking detection by technical means. Similar to the detection method used by the cable gland, this embodiment uses a position detection sensor to detect the real-time position of the high-voltage fuse inside the non-quick-release MSD. If the real-time position of the high-voltage fuse is abnormal, it is determined that the non-quick-release MSD has a fault.

[0037] Combination Figure 7 , Figure 7 This is a schematic diagram of the installation scheme for installing a position detection sensor inside a non-quick-release MSD. The positions of the outer cover 16 of the non-quick-release MSD, the high-voltage fuse 17, the copper bars (including bolt fixing holes) 18 on both sides of the high-voltage fuse, the installation base 19 of the equipment, and the avoidance hole 20 at the bottom of the high-voltage fuse for installing the position detection sensor are shown in the figure. The position detection sensor used in the non-quick-release MSD can be installed on the upper or lower side of the high-voltage fuse body, and the outlet of the position detection sensor can also be selected from the cover, side panel or bottom panel of the non-quick-release MSD, which can be selected according to actual needs. The detection form adopted by the position detection sensor used in the non-quick-release MSD can be a spring contact method, a Hall magnetic induction method, a telescopic contact type, and a proximity type. Specifically, when a position detection sensor of a shrapnel contact type is applied to a non-quick-release MSD, the flap of the position detection sensor can contact the body of the high-voltage fuse or the fixed copper busbar so that the shrapnel contacts the correspondingly arranged metal short-circuit to connect the circuit. According to the on-off of the circuit, it can be determined whether the real-time position of the high-voltage fuse is abnormal, that is, whether the non-quick-release MSD has a fault; when a position detection sensor of a Hall magnetic induction type is applied to a non-quick-release MSD, the flap of the position detection sensor can contact the body of the high-voltage fuse or the fixed copper busbar so that the magnet is close to the correspondingly arranged Hall sensor to connect the circuit; when a telescopic contact type position detection sensor is applied to a non-quick-release MSD, the telescopic compensation rod of the position detection sensor can be squeezed by the body of the high-voltage fuse or the fixed copper busbar so that the telescopic compensation rod contacts the corresponding contact through the spring-connected active short-circuit to connect the circuit; when a proximity type position detection sensor is applied to a non-quick-release MSD, the Hall detection end of the position detection sensor is fixedly connected to the body of the high-voltage fuse or the fixed copper busbar to detect the real-time position of the high-voltage fuse.

[0038] In summary, in combination with Figure 7 , the figure shows various types of position detection sensors and several positions available for arrangement, including the lower surface inside the cover, and routing the detection result out through the cover or side routing. When the position detection sensor of this embodiment is applied to a non-quick-release MSD, it can perform real-time position detection on the upper surface of the high-voltage fuse body or the upper surface of the fixed copper bars on both sides (upper installation), or can also perform detection by passing through the installation substrate of the non-quick-release MSD at the bottom of the high-voltage fuse body (lower installation). When the high-voltage fuse (or short-circuit copper bar of the non-quick-release MSD, for cost reduction, some MSDs do not install a high-voltage fuse inside but use a short-circuit copper bar to directly short-circuit the circuit instead of the fuse) and the outer cover of the non-quick-release MSD are installed in place, the detection circuit of the position detection sensor is connected. When the outer cover of the non-quick-release MSD is removed or the high-voltage fuse (or fixed copper bar) inside the MSD is removed (or there is disassembly looseness and displacement), the circuit of the position detection sensor is disconnected, indicating an abnormal real-time position, so as to realize the installation state detection of the non-quick-release MSD without an interlock detection pin, and the result of the installation state detection directly corresponds to whether there is a fault at this position.

[0039] Illustrated with a specific application example, the power battery system is formed by connecting multiple battery packs in series and parallel through a series-parallel structure. Each battery pack contains a battery management system BMS inside. The slave controller of the battery management system BMS is used to collect various information of the battery cells and summarize and upload it to the master controller of the battery management system BMS, and further extract the information and send it to the vehicle controller VCU. So in essence, each battery pack is an independent small assembly. The high-voltage interfaces of a single battery pack include the positive and negative poles of the main circuit, the positive and negative poles of the heating film circuit, and the MSD of the battery pack, etc. Most of the positive and negative interfaces of the battery pack on the market are currently connected by junction boxes with gland heads, and most MSDs are non-quick-release types. Therefore, the positive and negative interfaces of the battery pack and the MSD can adopt the gland head detection method and the non-quick-release MSD detection method described above in this embodiment for low-voltage alternative detection. The detection signal is connected to the corresponding acquisition pins of the slave controller of the BMS inside the battery pack, and the slave controller of the battery management system BMS undertakes the slave function of the detection controller, or installs a small-scale slave controller for detecting the conduction of the high-voltage cable to realize state acquisition and the ability to send out through CAN messages. The leads of the detection sensors corresponding to each connection part (quick-release part, gland head or non-quick-release MSD) are completely connected to the detection unit inside the battery pack. The detection status information of each pack is sent to the BMS master controller in real time through the subnet CAN for communication between the BMS master controller and the slave controller of each pack, and is sent out by the BMS master controller through the CAN line connectable to the vehicle to the master controller of the detection controller or the vehicle controller VCU and other controllers that essentially replace the detection master controller, so that the controller can obtain the detection result information in real time and process it to determine the targeted fault handling strategy and issue instructions.

[0040] Return to step S2. In step S2.2, before applying high voltage to the detection loop (when receiving the high-voltage application instruction during ON power), perform a real conduction detection on the detection loop. The real conduction detection includes injecting a pulse detection signal into the detection loop. If all detection points on the detection loop correctly receive the pulse detection signal, it indicates that the detection loop is conductive; if the detection loop is not conductive, find the first detection point that fails to correctly receive the pulse detection signal along the signal propagation direction as the location where the fault occurs. This detection method is the high-voltage line pulse injection conduction detection, which is an existing method of using special signal pulses for detection. However, in the prior art, the pulse injection detection is mostly only used for the interlock loop, while in this embodiment, the pulse injection detection is directly used to detect the high-voltage loop. Specifically explained in combination with the actual scenario, detecting the interlock loop is essentially an alternative detection; although the interlock loop detection can determine that the interlock pins of the high-voltage plug-in are in a conductive state, if the high-voltage cable is damaged due to a car accident or other accidents, even if it is determined through the interlock loop detection that the plug-in and the low-voltage cable are intact, it cannot be determined that the high-voltage loop is intact based on this. Therefore, in this embodiment, while performing alternative detection, a real conduction detection of the high-voltage loop is also performed through pulse injection detection to comprehensively ensure the true integrity of the loop. In addition, if the detection loop is a motor control loop, perform a motor control loop pulse injection detection. Each loop with a motor controller can use this method to independently perform a real conduction detection on the high-voltage loop where its load is located when detection is required.

[0041] Illustrated with a specific example, taking the detection of the battery pack heating film loop as an example, there are several series-connected battery heating films in each battery pack. In this embodiment, the heating films in the same battery pack are equivalent to a single resistor, and the heating films of different battery packs in the unified series loop of the battery system are equivalent to a series of resistors connected in series. Different parallel battery branches form equivalent resistor strings with different parallel numbers. For the conduction detection of the high-voltage loop formed by the equivalent resistor strings, in addition to using the above-mentioned fast plug-in detection method to detect through the interlock pins of the heating loop plug-in, a real conduction detection of the high-voltage loop is also required, such as Figure 9 As shown in the left part of the figure, the positive and negative poles of each series branch of the battery heating high-voltage loop are finally connected to the high-voltage power distribution cabinet PDU or the battery power distribution cabinet BDU. Corresponding numbers of positive and negative detection pins can be set on the high-voltage detection controller of the corresponding power distribution cabinet. The measurable voltage range of the detection pins is greater than the actual voltage range during battery and system operation to ensure the effectiveness, accuracy, and safety of the detection. All detection pins have the functions of sending, receiving, and voltage detection of pulse waveforms. The equivalent circuit diagram for the detection of the battery pack heating film loop is shown in Figure 8 .

[0042] like Figure 9 As shown in the left circuit of the high-voltage conduction detection circuit diagram of the middle battery pack, the positive pole of the heating circuit of each branch is connected from the high-voltage power distribution cabinet PDU or the battery distribution cabinet BDU, passes through the positive pole plug-in of the heating circuit of each battery pack, passes through several internal PTC heating films, and then connects from the negative pole plug-in of the heating circuit of the battery pack, and then enters the positive pole plug-in of the heating circuit of the next battery pack, until it returns to the negative pole plug-in of the heating corresponding circuit of the PDU or BDU. At this time, high-voltage detection pins are arranged between the positive pole plug-in of the heating circuit of each battery pack and the heating film (equivalent resistance) in the battery pack, and between the heating film (equivalent resistance) in the battery pack and the negative pole of the heating circuit of the battery pack (of course, high-voltage detection pins can also be set between the heating films in the pack, but the detailed and rich subdivision detection and fault location will bring the disadvantage of high cost). When ON receives the high voltage command, the high voltage detection controller in the high voltage distribution cabinet PDU or the battery distribution cabinet BDU sends a pulse waveform of a specific frequency, amplitude or duty cycle set by the program through the high voltage detection pin of the heating high voltage circuit negative pole or the heating high voltage circuit positive pole (used to distinguish from the detection waveforms of other high voltage circuits and functions, and to send and identify differentiated detection signals to avoid signal crosstalk caused by the common connection of the negative circuit and the connection of all high voltage circuits of the vehicle after the high voltage is turned on). When the pulse detection signal of this high voltage circuit is sent, each detection point on this high voltage circuit can receive and correspondingly identify the detection. The initial real conductivity detection only detects and identifies the specific pulse signal corresponding to this high voltage circuit as the judgment basis. If all detection points receive the correct pulse signal in time, it can indicate that the current high voltage circuit is truly conductive (the alternative judgment result of the cable installation status detection of the non-interlocking circuit is a direct conductivity judgment result).

[0043] In this application, the interlock detection of the connection components (quick plugs, cable glands, non-quick-release MSDs) and the real conductivity detection by injecting pulse detection signals complement each other. In the actual detection process, when the high-voltage circuit is blocked due to factors such as virtual connection, disconnection or plug removal, the next detection point along the signal propagation direction at the fault point and all subsequent corresponding circuit high-voltage detection points will not be able to receive the correct detection signal. Therefore, the fault point location can be preliminarily determined, and reverse signal detection verification can be performed. For example, the positive pole of the heating circuit of the high-voltage distribution cabinet PDU is used to send a signal in the initial stage, and the negative pole of the heating circuit of the high-voltage distribution cabinet PDU is used to send a signal with the same characteristics in the reverse direction. If all high-voltage monitoring points after the fault point are still unable to receive the correct signal according to the new signal propagation direction, the high-voltage signal detection controller slave inside the battery pack corresponding to the fault point can upload the judgment information to the BMS (when the BMS slave controller also serves) or the vehicle's detection master controller (with a dedicated high-voltage detection slave controller) through CAN communication and send it to the vehicle controller VCU and instrument and other receiving controllers.

[0044] Another specific application example is used for illustration. Taking the detection of battery system components as an example, similar to the independent detection of each power battery pack, the battery system also includes some other components with high-voltage cables, such as battery water cooling, on-board slow charger (OBC), battery distribution cabinet (BDU) of the battery system, etc. The method of this embodiment can be used to perform cable position supplementary detection on all plug-ins without quick plug-in connection detection terminals (cable heads, non-quick-release parts and other plug-ins with similar functions). The plug-in on the device side can be controlled by a slave of a high-voltage detection controller installed inside the device or by its own controller to perform detection or detection cable connection to the high-voltage detection controller in the battery distribution cabinet BDU for unified plug-in connection status detection, and perform cable conductivity pulse signal reception detection before high voltage is applied, and perform real-time monitoring and collection of voltage after the circuit is powered on after high voltage is applied, and send the detection result message to the battery management system BMS main control for summary and unified external transmission.

[0045] To further explain in detail, in combination with the foregoing, in addition to the cable installation status detection, which is an alternative determination detection of the high-voltage cable installation status using a low-voltage circuit, the present embodiment also directly performs a conductivity detection on the high-voltage circuit and locates the fault point to achieve the conductivity monitoring of the high-voltage circuit and determine the location of the fault point in order to troubleshoot and characterize the fault.

[0046] Returning to step S2, step S2.3 performs a real-time continuity test on the detection circuit after the high voltage is applied to the detection circuit. The real-time continuity test includes obtaining the real-time voltage or real-time current of the detection point pre-arranged on the detection circuit; taking the detection point where the real-time voltage or real-time current does not conform to the preset normal value as the fault point to determine the location of the fault.

[0047] Let's use a specific example to illustrate this. For example, the battery pack's main circuit conductivity and MSD fuse detection are used. The battery pack's MSD (Maintenance Switch Disconnector) is often set in the middle of all the battery cells in series in a battery pack, which plays a role in halving the voltage of the entire pack when it is removed or blown. There is a half-group of series-connected battery cells between the MSD and the positive plug-in of the battery pack, and between the MSD and the negative plug-in of the battery pack (the total positive side battery cell group and the total negative side battery cell group, respectively). Figure 9The half-group of series-connected cells is equivalent to a cell for illustration. There are voltage detection points at both ends of the half-group of cells to monitor the voltage value at both ends of the cells in real time. When the MSD is well connected and in good condition without being blown, the voltage of the pre-arranged detection points at both ends of the MSD is the same. If the MSD is blown, the breakpoint close to the total negative side is the highest voltage of the total negative side cell group, and the breakpoint close to the total positive side is the lowest potential relative to the high-voltage detection ground. The voltages of the detection points upward are accumulated one by one, so that when the MSD is disassembled or virtually connected and the high-voltage fuse in the MSD is blown, the voltage accumulation value can be continuously calculated. The accurate MSD installation connection and conduction or fuse status are detected, and combined with the detection results of the cable position detection sensor, the specific detailed fault type is analyzed, whether it is dismantled or not dismantled but blown, and reported through a message (the impact site of the traffic accident may also cause the cable to break or break the skin short circuit, resulting in MSD fusing, etc., but in addition to the obvious damage and actual reasons that can be inspected from the appearance, this solution can still effectively locate the internal injury type and accurate fault point that are not easy to judge from the appearance, and make a comprehensive judgment and detailed analysis), and the cable is manually disassembled for inspection and confirmation and replaced for repair.

[0048] Similarly, the voltage detection points of the positive battery plug-in between the battery packs and the negative battery plug-in of another pack are connected through the high-voltage transition cable between the battery packs. The voltages of the two detection points should be at the same potential. Any one of the plug-ins is loosely connected or removed, or other conduction abnormalities will cause the voltage value to be not at the same potential. The voltage value measured at the detection point closer to the high-potential side of the series circuit is changed to the lowest potential relative to the high-voltage detection ground. By calculating from the beginning, it can be found which two battery packs have problems with the conduction status of the positive and negative high-voltage cable connectors, and combined with the detection results of the cable positions of the two plug-ins and the external appearance inspection, it can be determined and quickly located to obtain the location of the fault and the specific cause.

[0049] Furthermore, the real-time conductivity detection can also adopt the breakpoint segmentation detection method. Specifically, when there is more than one breakpoint in the same branch, the signal is sent from both sides according to the forward and reverse methods mentioned above. In this way, only the end breakpoints close to both sides of the loop can be found, but the intermediate detection points cannot receive signals, and the specific conductivity of the intermediate line cannot be known, forming an intermediate detection blind area. At this time, the first detection point in the intermediate detection blind area can send a detection pulse signal to the upstream and downstream, and the remaining monitoring points in the intermediate detection blind area detect and recover it. If all signals can be received, there are only the identified breakpoints at both ends of the blind area. If there are still detection points that cannot obtain detection signals, they are further segmented and continue to be checked in this way until all breakpoints are identified and reported in summary.

[0050] An illustration is given with a specific example. Taking the real-time conductivity detection of the battery pack heating film circuit as an example, after applying high voltage, the heating circuit relay closes. During the process of the heating circuit conducting high voltage and being in use, the voltage of the power battery drops across the equivalent resistance of the heating film in each battery pack and gradually decreases to 0V. The high-voltage detection circuit connected across both sides of the heating resistor can detect the voltages on both sides of the heating resistor. The voltage difference between the two sides is the voltage drop due to voltage division. In fact, the two sets of detection points between the two battery packs are short-circuited through high-voltage transition cables, and the voltage value should be equal to the voltage value after the voltage drop due to voltage division of the heating resistor inside the previous battery pack. However, when there is a loose connection or break in the circuit or a fault in the heating film causing an open circuit, the entire heating circuit cannot form a closed circuit, no current can be formed, and thus no voltage drop can be formed across the equivalent resistance of each heating film. Therefore, all the detection points above the break are the same as the battery voltage, and all the detection points from the break closest to the negative electrode to the negative electrode are the voltages measured to the ground at the negative electrode. For all the paths between the two breaks, regardless of the number of breaks, the voltage is floating with respect to the ground. When there are more than two breaks and there is a floating voltage in the middle section, a method of sending pulses at the detection points in the middle section can be used for further break detection. Thus, the exact positions of all the breaks can be monitored and determined in real time when the high voltage is conducting to determine the location where the fault occurs and report it.

[0051] An illustration is given with another specific example. Combining Figure 10 , taking the real-time conductivity detection of the permanent magnet motor system as an example, the braking air pump motor, steering oil pump motor, air conditioning compressor motor (with UVW three-phase lines built-in), battery water-cooled compressor motor (with water cooler built-in), driving main motor, upper-mounted driving or upper-mounted hydraulic motor, etc. of an electric vehicle are usually permanent magnet three-phase motors and are equipped with corresponding motor controllers. They receive the high-voltage DC positive and negative cables provided by the high-voltage power distribution cabinet PDU (water cooling may be connected to the battery power distribution cabinet BDU or high-voltage power distribution cabinet PDU). The driving current is output through the UVW three-phase AC cable. In addition to performing the low-voltage circuit detection on the connection parts of the interlock pins described above for the 5 cables, the real conductivity detection also needs to be carried out before applying high voltage, and the real-time conductivity detection needs to be carried out after power-on.

[0052] Taking the detection of the high-voltage DC cable of the motor system as an example, specifically, before applying high voltage, when the high-voltage detection controller inside the high-voltage power distribution cabinet PDU (or battery power distribution cabinet BDU) receives the high-voltage application instruction under ON power, it sends pulse waves with specific dedicated signal eigenvalues to the positive and negative high-voltage cables respectively. The MCU controller of the corresponding motor or the built-in high-voltage detection controller of the slave unit collects and receives this pulse and identifies and judges. When the collected value is consistent with the set value, it indicates that the current high-voltage circuit is conducting well. If the specified waveform is not received, there is a conduction fault in this high-voltage circuit. And based on the detection results of the cable installation status of the plug or gland (the quick-release part with an interlock pin directly uses the low-voltage interlock circuit, and the gland without an interlock pin uses the cable position detection signal circuit), it comprehensively determines whether the specific loose connection, disconnection, or short-circuit point is in the PDU plug, the MCU plug, or the intermediate cable open circuit, so as to finally determine the occurrence of the fault. After applying high voltage, real-time conductivity detection is carried out. The high-voltage detection lines on both sides of the motor system circuit continuously detect the corresponding circuit voltage values. When voltage detection data is lost or abnormal during the high-voltage application process of the motor system circuit, it is judged whether there is a loose connection or open circuit (such as disconnection or damage) in one side of the plug by whether the real-time measurement values on both sides seriously deviate from the theoretical voltage value range (if a closed circuit cannot be formed, situations such as equipotential of the conduction point will occur, rather than voltage division voltage drop), and the location where the fault occurs is determined.

[0053] Taking the three-phase AC cable detection of the motor system as an example, when the ON power receives the high-voltage command, the high-voltage detection controller built into the MCU (motor controller) of the corresponding motor collects and analyzes the MCU and the gland position signal of the corresponding motor three-phase cable or the interlocking pin signal circuit status of the quick plug to determine whether there is a fault in the current detection circuit. The MCU controller can also perform the collection and analysis function. At the same time, the three-phase high-voltage cable is tested for real conductivity. The detection method adopts pulse detection. A specific pulse waveform is given to one of the three-phase lines UVW (assumed to be U), and the pulse characteristics of the other two phases are monitored. The pulse frequency and duty cycle are checked for consistency. If waveforms with the same characteristic values are received, it is confirmed that the three-phase lines are well connected. When one line does not collect the correct pulse value (assumed to be W), replace another line to repeat the pulse sending (assumed to be V), and collect and analyze through the other two lines. If the U phase has the correct pulse data and the W phase still does not have the specific pulse value data, the W phase continues to output pulses. If the other two phases are not received, it can be determined that the W phase line and the plug-ins at both ends are virtual connected or open (such as removed, etc.), and then combined with the cable installation status of the fast plug-in, it is detected that the cable or the position of the plug-ins at both ends has a fault. After the high voltage has been normally supplied, it is necessary to continue to perform real-time conductivity detection on the high-voltage circuit of the motor. The motor controller can monitor the three-phase current in real time with the internal current detection module. When there is a drive output demand, all three phases have current values and they are normal. If there is an output demand but one or more phases have no current, it means that the corresponding circuit line is virtual connected or open, and the cable installation status of the connection part is detected and the actual conductivity test is comprehensively determined to determine the location of the fault.

[0054] Step S3: Determine whether there is a fault in the detection circuit according to the results of the cable installation status detection, the real conductivity detection and the real-time conductivity detection.

[0055] The cable installation status detection, true conductivity detection and real-time conductivity detection in this embodiment are applicable to most high-voltage circuits. For different high-voltage circuits, appropriate detection methods can be adaptively selected to obtain fault detection results.

[0056] On the basis of determining the detection circuit in step S1, the detection method in step S2 can be used to determine whether there is a detection fault that affects conduction in the detection circuit based on the detection results of the tests performed (quick plug detection, cable gland detection, non-quick release MSD detection, high-voltage line pulse injection conductivity detection, voltage detection).

[0057] Step S4: If there is a fault, determine the fault level by looking up a table according to the fault location and working mode; and determine the fault handling strategy according to the fault level.

[0058] In some specific embodiments, taking a pure electric vehicle as an example, according to whether it is equipped with a BDU (battery distribution cabinet) or not (the function is included in the PDU), whether it is equipped with a combined auxiliary drive (including the drivers of DCDC / steering DCAC and braking DCAC) or not (the function is included in the PDU), whether it is equipped with slow charging (the function is in the PDU or BDU), whether it is equipped with an upper-mounted drive MCU and an upper-mounted motor (the function is included in the PDU) or not, etc., the number of high-voltage cable channels in this embodiment is basically counted and divided into single or multiple cables (which can be one or several fast connectors with interlock pins or gland-type waterproof connectors that cannot add interlock pins), or multiple-core cables are connected to the corresponding control cabinet or equipment through fast connectors with interlock pins or single glands without interlock pins. When a definite conduction fault occurs in the outgoing line during the vehicle discharge and charging processes, the influence is further classified and counted according to the actual requirements and the severity of the risk, and is divided according to the national standard level 1-3 faults. The fault values in different modes can be different as required, forming Table 1 and Table 2. Among them, Table 1 is the cable interface statistics table mainly for power distribution, and Table 2 is the cable interface statistics table of the drive execution unit mainly for drivers, execution devices, charging devices, etc. It is used as the fault level table for determining the fault level in this embodiment. This embodiment determines the fault level according to the occurrence location of the fault and the working mode. The same fault occurrence location may be classified into different fault levels in the discharge mode or the charging mode, and each fault level corresponds to a fault handling strategy. It should be noted that Table 1 and Table 2 are only a specific example that can be adopted by the detection method of this embodiment. In the face of different application scenarios, the fault level table can be flexibly adjusted according to the actual requirements in the specific scenario.

[0059] On the basis of carrying out a complete fault detection, this embodiment has the prerequisite for such a detailed division of fault levels. This has obvious technical advantages compared with the traditional unified high-voltage strategy of reducing torque according to the vehicle's three-level faults or simply determining the unified level under local area differentiation. This embodiment can be refined and controlled in detail according to the actual necessity and relevance and perform targeted subsequent processing, so as to minimize the impact on the driving performance while ensuring safety. The national standard level 1 fault divided in the table is the least serious, only alarms without any restrictive strategy, the level 2 limits the charge and discharge power or torque and alarms, and the level 3 stops the torque output, decelerates and stops, then lowers the high voltage, and terminates the charge and discharge process.

[0060] This embodiment uses a high-voltage detection controller as a detection and monitoring unit for cable installation status detection (quick plug-in, cable gland, non-quick-release MSD) and various line conductivity tests (real conductivity detection before power-on and real-time conductivity detection after power-on). The high-voltage detection controller is divided into a master controller and a slave controller. The master controller or the slave controller can be designed into models with different specifications according to the pin resource requirements, and the controller can also be expanded as needed. For example, based on the pure electric high-voltage detection controller architecture, dedicated controllers can be deployed for each controller of the hydrogen fuel system and the high-voltage line system to achieve equipment and function expansion. Each high-voltage detection controller can also be concurrently served by a controller in the area where it is located.

[0061] Table 1. Fault level table of high voltage cable connectors for power distribution equipment

[0062] Table 2. High-voltage cable connectors and fault levels for drive, execution, and charging equipment

[0063] To explain in combination with the specific working mode, in the maintenance mode, the vehicle is not in operation, and it is only necessary to report the fault to the maintenance personnel, and there is no need to directly handle the fault in an emergency. In the charging mode, if a level 1 fault occurs, only an alarm will be issued without any restrictive strategy. If a level 2 fault occurs, the charging power will be limited and an alarm will be issued. If a level 3 fault occurs, it is necessary to terminate the charging in time, slow down and stop, then lower the high voltage, and intervene manually. Similarly, in the supplementary power mode, if a level 1 fault occurs, only an alarm will be issued without any restrictive strategy, and a processing strategy of limiting the supplementary power can be adopted. If a level 2 fault occurs, the supplementary power will be limited and an alarm will be issued. If a level 3 fault occurs, it is necessary to terminate the supplementary power in time, slow down and stop, then lower the high voltage, and intervene manually. The same applies to the discharge mode. Example

[0064] Based on the same inventive concept as in Example 1, this embodiment provides a high voltage circuit integrity detection system, which includes: A determination module, used for obtaining an operating mode of the vehicle and determining a high-voltage circuit related to the operating mode as a detection circuit; The test mode is used to detect the cable installation status of the connection parts on the detection circuit and the real conductivity test of the detection circuit before the high voltage is applied to the detection circuit; after the high voltage is applied to the detection circuit, the real-time conductivity test of the detection circuit is performed; A fault determination module, used to determine whether there is a fault in the detection circuit according to the results of the cable installation status detection, the real conductivity detection and the real-time conductivity detection; A processing module, configured to, if a fault exists, look up a table to determine a fault level according to the occurrence location of the fault; and determine a fault handling strategy according to the fault level.

[0065] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principles of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for detecting a high-voltage circuit of an electric vehicle, characterized in that, Including: Obtain the working mode of the vehicle, and determine the high-voltage circuit related to the working mode as the detection circuit; Before the high voltage is applied to the detection circuit, perform cable installation state detection on the connection parts on the detection circuit and perform real conduction detection on the detection circuit; After the high voltage is applied to the detection circuit, perform real-time conduction detection on the detection circuit; Determine whether there is a fault in the detection circuit according to the results of the cable installation state detection, real conduction detection and real-time conduction detection; If there is a fault, look up the fault level according to the occurrence location of the fault and the working mode; Determine the fault handling strategy according to the fault level.

2. The method for detecting the integrity of the high-voltage circuit of an electric vehicle according to claim 1, wherein, When the connection part uses a quick plug-in connection, the cable installation state detection on the connection part of the detection circuit includes: If the quick plug-in has an interlock pin, connect the interlock pin to the high-voltage detection controller to determine the connection locking state of the quick plug-in. If the connection locking state is abnormal, it is determined that there is a fault in the quick plug-in; If the quick plug-in does not have an interlock pin, use the spare signal line pin to replace the interlock pin and connect it to the high-voltage detection controller to determine the connection locking state of the quick plug-in. If the connection locking state is abnormal, it is determined that there is a fault in the quick plug-in.

3. The method for detecting the integrity of the high-voltage circuit of an electric vehicle according to claim 1, characterized in that When the connection part uses a gland connection, the cable installation state detection on the connection part of the detection circuit includes: Pre-install a cable position detection sensor in the junction box of the gland; Use the cable position detection sensor to detect the real-time position of the cable installed in the junction box. If the real-time position of the cable is abnormal, it is determined that there is a fault in the gland.

4. The method for detecting the integrity of the high-voltage circuit of an electric vehicle according to claim 3, characterized in that, The cable position detection sensor includes: A base, installed at the cover plate of the junction box; A flap, movably installed at the cover plate of the junction box; A shrapnel and a metal shorting piece, respectively installed on the base or the flap; After the cable is installed in place in the junction box, it can contact the flap, so that the shrapnel contacts the metal shorting piece to connect the circuit. If the circuit is disconnected, it means that the real-time position of the cable is abnormal.

5. The method for detecting the integrity of the high-voltage circuit of an electric vehicle according to claim 3, wherein The cable position detection sensor includes: A base, provided in the junction box, and a contact is provided on the base; A movable shorting piece, provided in the junction box, and a first spring is provided between the movable shorting piece and the junction box; A telescopic compensation rod, provided on the movable shorting piece and used to contact the cable, and a second spring is provided between the telescopic compensation rod and the movable shorting piece, and the elastic coefficient of the second spring is greater than that of the first spring; After the cable is installed in place in the junction box, it can compress the first spring and the second spring through the telescopic compensation rod. The first spring is compressed first so that the movable shorting piece contacts the contact to connect the circuit. If the circuit is disconnected, it means that the real-time position of the cable is abnormal.

6. The method for detecting the integrity of the high-voltage circuit of an electric vehicle according to claim 1, characterized in that The detection method further includes: Before the high voltage is applied to the detection circuit, detect the non-quick-release MSD; Detect the real-time position of the high-voltage fuse body in the MSD through a cable position detection sensor pre-installed in the MSD; If the real-time position of the high-voltage fuse body is abnormal, it is determined that there is a fault in the non-quick-release MSD.

7. The method for detecting the integrity of the high-voltage circuit of an electric vehicle according to claim 1, wherein The real conduction detection includes: Inject a pulse detection signal into the detection circuit. If all the detection points on the detection circuit correctly receive the pulse detection signal, it indicates that the detection circuit is conducting. If the detection circuit is not conducting, search for the first detection point that fails to correctly receive the pulse detection signal along the signal propagation direction to determine the location of the fault.

8. The method for detecting the integrity of the high-voltage circuit of an electric vehicle according to claim 1, wherein The real-time conductivity detection of the detection circuit includes: Obtain the real-time voltage or real-time current of the detection points arranged in advance on the detection circuit. Regard the detection points where the real-time voltage or real-time current does not conform to the preset normal value as fault points to determine the location of the fault.

9. The method for detecting the integrity of the high-voltage circuit of an electric vehicle according to claim 1, characterized in that The determination of the fault handling strategy in the current working mode according to the fault level includes: The fault level is divided into level one, level two, and level three. If the fault level is level one, only issue a warning. If the fault level is level two, limit the output power in the current working mode of the vehicle and issue a warning. If the fault level is level three, terminate the output of the current working mode of the vehicle, stop the vehicle, and cut off the high voltage.

10. An electric vehicle high-voltage circuit detection system, characterized in that, It includes: A determination module for obtaining the working mode of the vehicle and determining the high-voltage circuit related to the working mode as the detection circuit. A test mode for, before applying high voltage to the detection circuit, detecting the cable installation status of the connection parts on the detection circuit and performing real conductivity detection on the detection circuit; after applying high voltage to the detection circuit, performing real-time conductivity detection on the detection circuit. A fault determination module for determining whether there is a fault in the detection circuit according to the results of the cable installation status detection, real conductivity detection, and real-time conductivity detection. A processing module for, if there is a fault, looking up the table according to the location of the fault to determine the fault level. Determine the fault handling strategy according to the fault level.

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