An adhesion fault detection circuit for a high-side contactor

Abstract

The present invention discloses a detection circuit for the adhesion fault of a high-side contactor, which includes a contact detection input circuit. The first input end of the contact detection input circuit is connected to the positive terminal HVP of the power battery system; HVP is connected to the positive terminal B+ of the high N-series battery pack in the power battery system through the high-side contactor; the second input end and the third input end of the contact detection input circuit are respectively connected to the negative terminal of the high N-series battery pack and the output end of the BMS main control chip; the output end of the contact detection input circuit is respectively connected to the input end of the contact detection output circuit and the second input end of the coil start detection circuit; the output end of the contact detection output circuit is connected to the BMS main control chip; the first input end of the coil start detection circuit is connected to an external coil drive circuit; the output end of the coil start detection circuit is connected to the BMS main control chip. The present invention does not require manual troubleshooting, can accurately determine whether the contacts of the high-side contactor have adhesion faults, and improves the detection efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and particularly to a detection circuit for the adhesion fault of a high-side contactor. Background Art

[0002] A battery management system (hereinafter referred to as BMS) is a battery protection device and also a bridge between the battery and the load terminal. It provides protection functions such as overcharge, over-discharge, and over-temperature for the battery according to the actual usage status of the battery monitored online to ensure the safe use of the battery. The battery management system BMS is widely used in many fields such as electric vehicles, communication base stations, and robots.

[0003] Taking electric vehicles as an example, in a vehicle-mounted power battery system (hereinafter referred to as the power battery system), a DC contactor (hereinafter referred to as the contactor) is generally used as a switching device for the high-voltage circuit of the battery system. It is a key electrical component in the battery system and is controlled by the BMS or the vehicle-mounted electronic control system for its on / off. In actual use, due to the impact of large currents, sometimes the contactor contact adhesion fault occurs, causing the positive and negative terminals of the power battery system to still have high voltage. At this time, it will pose a great safety risk to the vehicle and the operator.

[0004] Among them, the reasons for the safety risks to the vehicle and the operator include: the BMS does not detect the adhesion of the contactor contacts and cannot detect the contact adhesion fault of the contactor, so it cannot give an alarm in time to remind the operator to manually disconnect the high-voltage circuit before maintenance.

[0005] In view of the above problems, some existing technical solutions use an optocoupler chip to directly sample the high voltage at both ends of the power battery system to detect the contact adhesion fault of the contactor. However, these solutions can only initially judge that it is a contact adhesion fault of the contactor, but cannot determine whether it is really a contact adhesion fault. If it is necessary to determine whether it is a contact adhesion fault, when it is judged as a contact adhesion fault, it is also necessary to further manually check the specific cause of the fault: whether the contact is not disconnected because the contactor coil power supply is not disconnected, or whether it is indeed a contact adhesion fault.

[0006] In addition, in the existing detection technical solutions, since the high voltage is directly detected, the price of the selected optocoupler chip is also very high, resulting in a high hardware cost of the BMS. Summary of the Invention

[0007] The purpose of the present invention is to provide a detection circuit for the adhesion fault of a high-side contactor in view of the technical defects existing in the prior art.

[0008] To this end, the present invention provides a detection circuit for the adhesion fault of a high-side contactor, which includes a contact detection input circuit, a contact detection output circuit, a coil start detection circuit, and a BMS main control chip;

[0009] Among them, for the contact detection input circuit, its first input terminal is connected to the positive terminal HVP of the power battery system, and is used to receive the positive terminal voltage of the high-N series battery pack in the power battery system;

[0010] The positive terminal HVP of the power battery system is connected to the positive terminal B+ of the high-N series battery pack in the power battery system through the high-side contactor KL1;

[0011] The high-N series battery pack is a plurality of series-connected single cells in the power battery system close to the high-side contactor KL1;

[0012] Among them, for the contact detection input circuit, its second input terminal is connected to the negative terminal BH- of the high-N series battery pack in the power battery system, and is used to receive the negative terminal voltage of the power battery system;

[0013] Among them, for the contact detection input circuit, its third input terminal is connected to the output terminal KC1 of the BMS main control chip, and is used to receive and execute the switch control signal KC1 output by the BMS main control chip;

[0014] Among them, for the contact detection input circuit, its output terminal is respectively connected to the input terminal of the contact detection output circuit and the second input terminal of the coil start detection circuit, and is used to control the on-off of the contact detection output circuit and the coil start detection circuit;

[0015] For the contact detection output circuit, its output terminal B is connected to the first input terminal of the BMS main control chip, and is used to output a contact detection signal B to the BMS main control chip 400;

[0016] For the coil start detection circuit, its first input terminal KLC is connected to an external coil drive circuit, and is used to receive the coil start signal sent by the external coil drive circuit;

[0017] For the coil start detection circuit, its output terminal A is connected to the second input terminal of the BMS main control chip, and is used to output a coil start detection signal A to the BMS main control chip;

[0018] The BMS main control chip is used to receive the contact detection signal B conveyed by the contact detection output circuit and the coil start detection signal A output by the coil start detection circuit. When power is on under high voltage or power is off after high voltage, if the contact detection signal B at the output terminal B of the contact detection output circuit is at a high level, and the coil start detection signal A at the output terminal A of the coil start detection circuit is at a low level, then it is determined that the high-side contactor KL1 has an adhesion fault.

[0019] Preferably, the BMS master control chip is further configured to, when judging that the high-side contactor KL1 has an adhesion fault before high-voltage power-on or after high-voltage power-off, send a low-level switch control signal KC1 to the signal input end of the switch K1 in the contact detection input loop, disconnect the switch K1, and end the adhesion detection.

[0020] Preferably, the BMS master control chip is further configured to, when high-voltage power-on occurs, if the contact detection signal B at the output end B of the contact detection output loop and the coil start detection signal A at the output end A of the coil start detection loop are both at a high level, determine that the high-side contactor KL1 has been activated by high voltage; otherwise, determine that the high-side contactor KL1 has not been activated by high voltage.

[0021] Preferably, the contact detection input loop includes a resistor R1, a resistor R2, a switch K1, a capacitor C1, a resistor R3, a diode D1, an optocoupler Q1, a resistor R4, and a resistor R6, where:

[0022] The negative electrode end of the high-N series battery pack in the power battery system is connected to one end of the switch K1;

[0023] One end of the switch K1 serves as the second input end of the contact detection input loop;

[0024] The first pin of the resistor R1 serves as the first input end of the contact detection input loop and is connected to the positive electrode end HVP of the power battery system;

[0025] The second pin of the resistor R1 is respectively connected to the first pin of the resistor R2, the first pin of the capacitor C1, and the first pin of the resistor R3;

[0026] The second pin of the resistor R2 is connected to the other end of the switch K1;

[0027] The second pin of the resistor R2 is also respectively connected to the second pin of the capacitor C1, the second pin of the optocoupler Q1, and the anode of the diode D1;

[0028] Among them, the signal input end of the switch K1 serves as the third input end of the contact detection input loop and is connected to the output end KC1 of the BMS master control chip;

[0029] The second pin of the resistor R3 is respectively connected to the first pin of the optocoupler Q1 and the cathode of the diode D1;

[0030] The third pin of the optocoupler Q1 is connected to the second pin of the resistor R4;

[0031] The fourth pin of the optocoupler Q1 is grounded;

[0032] The first pin of the resistor R4 is respectively connected to the second pin of the resistor R6 and the base of the switching transistor Q2;

[0033] The first pin of resistor R6 is respectively connected to the second pin of resistor R5 and the emitter of switching transistor Q2.

[0034] Preferably, the contact detection output circuit includes:

[0035] Resistor R5, switching transistor Q2 and resistor R7, where:

[0036] The first pin of resistor R5 is connected to the external DC power supply of 5V;

[0037] The collector of switching transistor Q2 is respectively connected to the output terminal B of the contact detection output circuit and the first pin of resistor R7;

[0038] The second pin of resistor R7 is grounded.

[0039] Preferably, the coil start detection circuit includes: resistor R8, switching transistor Q3 and resistor R9, where:

[0040] The base of switching transistor Q3 serves as the second input terminal of the coil start detection circuit and is connected to the third pin of optocoupler Q1;

[0041] The emitter of switching transistor Q3 is connected to the second pin of resistor R8;

[0042] The first pin of resistor R8 serves as the first input terminal of the coil start detection circuit, which is used to connect to an external coil drive circuit for receiving a coil start signal sent by the external coil drive circuit;

[0043] The collector of switching transistor Q3 is respectively connected to the output terminal A of the coil start detection circuit and the first pin of resistor R9;

[0044] The second pin of resistor R9 is grounded.

[0045] Preferably, before the high-voltage power-on and after the high-voltage power-off of the power battery system, the BMS main control chip determines whether there is a contact adhesion fault of the high-side contactor KL1 according to the combined logic of the coil start detection signal A output from the output terminal A of the coil start detection circuit and the contact detection signal B output from the output terminal B of the contact detection output circuit. The judgment conditions are as follows:

[0046] 1. When both the coil start detection signal A and the contact detection signal B are low levels, it is determined that the contacts of the high-side contactor KL1 are not adhered;

[0047] 2. When the coil start detection signal A is at a low level and the contact detection signal B is at a high level, it is determined that the contacts of the high-side contactor KL1 are adhered.

[0048] Preferably, when the power battery system is powered on at high voltage, the BMS main control chip determines whether the high-side contactor KL1 has been activated at high voltage according to the combined logic of the detection signal B output from the output terminal B of the contact detection output circuit and the coil start detection signal A output from the output terminal A of the coil start detection circuit. The judgment conditions are as follows:

[0049] 1. When both the coil start detection signal A and the contact detection signal B are at high level, it is determined that the high-side contactor KL1 has been activated at high voltage;

[0050] 2. When both the coil start detection signal A and the contact detection signal B are at low level, it is determined that the high-side contactor KL1 has not been activated at high voltage.

[0051] As can be seen from the technical solutions provided by the present invention above, compared with the prior art, the present invention provides a sticking fault detection circuit for a high-side contactor, which can accurately determine whether the contacts of the high-side contactor are stuck without manual troubleshooting, can significantly improve the detection efficiency, and has great practical significance.

[0052] In addition, the sticking fault detection circuit for a high-side contactor provided by the present invention has a scientific hardware circuit design, does not occupy additional port resources of the BMS main control chip. Since it does not directly detect high voltage, the electronic components are commonly used models, which are easy to select. Moreover, the circuit board occupies a small space and the design cost is very low. It is a technical solution that is easy to select components and has a low cost. Therefore, the technical solution of the present invention has strong practical value and market promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a block diagram of the overall structure of a sticking fault detection circuit for a high-side contactor provided by the present invention;

[0054] Figure 2 It is a specific connection schematic diagram of a sticking detection circuit for the contacts of a high-side contactor provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] To make the technical means implemented by the present invention easier to understand, the following further details the present application in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the relevant application, rather than limiting the application. In addition, it should be noted that for the convenience of description, only the parts related to the present application are shown in the drawings.

[0056] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will detail the present application with reference to the drawings and embodiments.

[0057] See Figure 1 、 Figure 2, the present invention provides a sticking fault detection circuit for a high-side contactor, which includes a contact detection input circuit 100, a contact detection output circuit 200, a coil start detection circuit 300, and a BMS main control chip 400;

[0058] Among them, for the contact detection input circuit 100, its first input terminal is connected to the positive terminal HVP of the power battery system, and is used to receive the positive terminal voltage of the high N-series battery pack in the power battery system; it should be noted that in specific implementation, the first input terminal of the contact detection input circuit 100 is connected to the positive terminal HVP of the power battery system;

[0059] The positive terminal HVP of the power battery system is connected to the positive terminal B+ of the high N-series battery pack in the power battery system through the high-side contactor KL1.

[0060] Among them, N is the number of series-connected single cells, and is less than the total number of series-connected single cells in the battery system. In actual application, a suitable N should be selected according to the total number of series-connected batteries in the battery system.

[0061] The positive terminal of the power battery system is provided with a high-side contactor KL1;

[0062] It should be noted that as shown in Figure 1 The high N-series battery pack is a plurality of series-connected single cells in the power battery system close to the high-side contactor KL1. There are N series-connected single cells between the positive terminal B+ (i.e., the positive terminal of all batteries) and the negative terminal BH- of the high N-series battery pack. Among them, the positive terminal B+ of the high N-series battery pack is connected to the positive terminal HVP of the power battery system through the high-side contactor KL1.

[0063] In the present invention, as shown in Figure 1 the negative terminal HVN of the power battery system is the negative output terminal B- of the power battery system including all series-connected single cells.

[0064] Among them, for the contact detection input circuit 100, its second input terminal VP1 is connected to the negative terminal BH- of the high N-series battery pack in the power battery system, and is used to receive the negative terminal voltage of the high N-series battery pack in the power battery system;

[0065] It should be noted that in specific implementation, the first input terminal of the contact detection input circuit 100 is connected to the positive terminal HVP of the power battery system. Correspondingly, the second input terminal of the contact detection input circuit 100 is connected to the negative terminal BH- of the high N-series battery pack in the power battery system. The contact detection input circuit 100 is used to receive the voltage of the high N-series battery pack in the power battery system.

[0066] Among them, the contact detection input circuit 100, whose third input terminal is connected to the output terminal KC1 of the BMS main control chip, is used to receive and execute the switch control signal KC1 output by the BMS main control chip;

[0067] Among them, the output terminal of the contact detection input circuit 100 is respectively connected to the input terminal of the contact detection output circuit 200 and the second input terminal of the coil start detection circuit 300, and is used to control the on-off of the two circuits of the contact detection output circuit 200 and the coil start detection circuit 300.

[0068] The output terminal B of the contact detection output circuit 200 is connected to the first input terminal of the BMS main control chip 400, and is used to output the contact detection signal B to the BMS main control chip 400;

[0069] The first input terminal KLC of the coil start detection circuit 300 is connected to an external coil drive circuit, and is used to receive the coil start signal sent by the external coil drive circuit, and this coil start signal is the KLC signal;

[0070] The output terminal A of the coil start detection circuit 300 is connected to the second input terminal of the BMS main control chip 400, and is used to output the coil start detection signal A to the BMS main control chip 400;

[0071] The BMS main control chip 400 is used to receive the contact detection signal B conveyed by the contact detection output circuit 200 and the coil start detection signal A output by the coil start detection circuit 300. When before high-voltage power-on or after high-voltage power-off, if the contact detection signal B at the output terminal B of the contact detection output circuit 200 is high level, and the coil start detection signal A at the output terminal A of the coil start detection circuit 300 is low level, then it is determined that the high-side contactor KL1 has an adhesion fault.

[0072] Specifically, the BMS main control chip 400 is further used to, when before high-voltage power-on or high-voltage power-off of the power battery system and after determining that the high-side contactor KL1 has an adhesion fault, send a low-level switch control signal KC1 to the signal input terminal of the switch K1 in the contact detection input circuit 100 to disconnect the switch K1, so that the adhesion detection ends.

[0073] Specifically, the BMS main control chip 400 is further used to, when the power battery system is powered on at high voltage, if the contact detection signal B at the output terminal B of the contact detection output circuit 200 and the coil start detection signal A at the output terminal A of the coil start detection circuit 300 are both high level, it is determined that the high-side contactor KL1 has been activated at high voltage, otherwise, it is determined that the high-side contactor KL1 has not been activated at high voltage.

[0074] It should be noted that for high-voltage power-on and high-voltage power-off, both are controlled by the BMS main control chip 400, which controls the on-off of the high-side contactor KL1 set at the positive extreme of the power battery system to achieve the control of high-voltage power-on and power-off of the power battery system.

[0075] Among them, for the external coil drive circuit, the coil power supply signal provided by the external coil drive circuit has two states: high potential and low potential. The high-potential coil power supply signal indicates that the contactor coil is powered on (that is, the high-side contactor coil is powered on), and the low-potential coil power supply signal indicates that the contactor coil has been powered off (that is, the high-side contactor coil has been powered off).

[0076] It should be noted that the external coil drive circuit is a circuit commonly used in the current BMS technical solution, which is an existing conventional circuit design and a well-known circuit structure, so it will not be elaborated here. In the present invention, the present invention only uses the signal of the high and low potential of the coil power supply provided by this existing external coil drive circuit.

[0077] It should be noted that in Figure 1 , the high-N series battery pack and the high-side contactor KL1 do not belong to the technical solution of the present invention, and are only shown for the convenience of understanding the technical solution of the present invention.

[0078] To more clearly understand the technical solution of the present invention, the working principle of the invention will be described below by taking the detection of the high-side contactor KL1 as an example:

[0079] When detecting the high-side contactor KL1, the first input end of the contact detection input circuit 100 is connected to the positive extreme HVP of the power battery system, and the second input end is connected to the negative extreme BH- of the high-N series battery pack;

[0080] It should be noted that under normal conditions, before high-voltage power-on and after high-voltage power-off, the contacts of the high-side contactor KL1 should be disconnected. The voltage HVP at the first input end (used to connect the positive extreme HVP) of the contact detection input circuit 100 is 0V. The potential of the second input end VP1 of the contact detection input circuit 100 (used to connect the negative extreme BH- of the high-N series battery pack) is equal to the voltage BH- of the battery negative electrode in the power battery system. The input signal KLC received by the input end of the coil start detection circuit 300 is at a low potential (the high-side contactor KL1 coil is not powered on, and at this time, the state of the coil power supply signal provided by the external coil drive circuit is: a low-potential coil power supply signal). The coil start detection signal A output by the output end A of the coil start detection circuit 300 and the contact detection signal B output by the output end B of the contact detection output circuit 200 are at a low level.

[0081] Therefore, for the present invention, before the high-voltage power-on and after the high-voltage power-off of the power battery system, in order to detect and judge whether the high-side contactor KL1 is working properly, the BMS main control chip 400 determines whether there is a contact sticking fault of the high-side contactor KL1 according to the combined logic of the coil start detection signal A output from the output terminal A of the coil start detection circuit 300 and the contact detection signal B output from the output terminal B of the contact detection output circuit 200. The judgment conditions are as follows:

[0082] 1. When both the coil start detection signal A and the contact detection signal B are low levels, it is determined that the contacts of the high-side contactor KL1 are not stuck.

[0083] 2. When the coil start detection signal A is at a low level and the contact detection signal B is at a high level, it is determined that the contacts of the high-side contactor KL1 are stuck.

[0084] It should be noted that under normal conditions, when the high-voltage power is on, the input signal KLC of the input terminal KLC of the coil start detection circuit 300 changes from a low potential to a high potential (because at this time, the coil of the high-side contactor KL1 is powered on, so the coil power signal provided by the external coil drive circuit is a high-potential coil power signal). The contacts of the high-side contactor KL1 are attracted, and the voltage of the positive terminal HVP of the power battery system changes from 0V to the positive terminal voltage B+ of the high N-series battery pack, causing the contact detection signal B output from the output terminal B of the contact detection output circuit 200 and the coil start detection signal A output from the output terminal A of the coil start detection circuit 300 to change from low levels to high levels. When the high-voltage power is on, the coil start detection signal A and the contact detection signal B remain at high level states.

[0085] Therefore, for the present invention, in order to detect and judge whether the high-side contactor KL1 is working properly, when the high-voltage power of the power battery system is on, the BMS main control chip 400 determines whether the high-side contactor KL1 has been activated at high voltage according to the combined logic of the detection signal B output from the output terminal B of the contact detection output circuit 200 and the coil start detection signal A output from the output terminal A of the coil start detection circuit 300. The judgment conditions are:

[0086] 1. When both the coil start detection signal A and the contact detection signal B are at high levels, it is determined that the high-side contactor KL1 has been activated at high voltage;

[0087] 2. When the coil start detection signal A and the contact detection signal B are at low levels, it is determined that the high-side contactor KL1 has not been activated at high voltage.

[0088] In the present invention, in terms of specific implementation, refer to Figure 2 As shown, the contact detection input circuit 100 includes a resistor R1, a resistor R2, a switch K1, a capacitor C1, a resistor R3, a diode D1, an optocoupler Q1, a resistor R4, and a resistor R6, where:

[0089] The negative extreme BH- of the high-N series battery pack in the power battery system is connected to one end of the switch K1;

[0090] One end of the switch K1 serves as the second input terminal of the contact detection input circuit 100; the first pin of the resistor R1 serves as the first input terminal of the contact detection input circuit 100 and is connected to the positive extreme HVP of the power battery system;

[0091] The second pin of the resistor R1 is respectively connected to the first pin of the resistor R2, the first pin of the capacitor C1, and the first pin of the resistor R3;

[0092] The second pin of the resistor R2 is connected to the other end of the switch K1;

[0093] The second pin of the resistor R2 is also respectively connected to the second pin of the capacitor C1, the second pin of the optocoupler Q1, and the anode of the diode D1;

[0094] Among them, the signal input terminal of the switch K1 serves as the third input terminal of the contact detection input circuit 100 and is connected to the output terminal KC1 of the BMS main control chip;

[0095] The second pin of the resistor R3 is respectively connected to the first pin of the optocoupler Q1 and the cathode of the diode D1;

[0096] The third pin of the optocoupler Q1 is connected to the second pin of the resistor R4;

[0097] The fourth pin of the optocoupler Q1 is grounded;

[0098] The first pin of the resistor R4 is respectively connected to the second pin of the resistor R6 and the base of the switching transistor Q2;

[0099] The first pin of the resistor R6 is respectively connected to the second pin of the resistor R5 and the emitter of the switching transistor Q2.

[0100] In the present invention, in terms of specific implementation, refer to Figure 2 As shown, the contact detection output circuit 200 includes: a resistor R5, a switching transistor Q2, and a resistor R7, where:

[0101] The first pin of the resistor R5 is connected to the external DC power supply 5V;

[0102] The collector of the switching transistor Q2 is respectively connected to the output terminal B of the contact detection output circuit 200 and the first pin of the resistor R7;

[0103] The second pin of the resistor R7 is grounded.

[0104] In the present invention, in terms of specific implementation, refer to Figure 2 As shown, the coil start detection circuit 300 includes: a resistor R8, a switching transistor Q3, and a resistor R9, where:

[0105] The base of the switching transistor Q3 serves as the second input terminal of the coil startup detection circuit 300 and is connected to the 3rd pin of the optocoupler Q1;

[0106] The emitter of the switching transistor Q3 is connected to the 2nd pin of the resistor R8;

[0107] The 1st pin of the resistor R8 serves as the first input terminal of the coil startup detection circuit 300, is used to connect an external coil drive circuit, and is used to receive a coil startup signal sent by the external coil drive circuit. This coil startup signal is the signal KLC;

[0108] The collector of the switching transistor Q3 is respectively connected to the output terminal A of the coil startup detection circuit 300 and the 1st pin of the resistor R9;

[0109] The 2nd pin of the resistor R9 is grounded.

[0110] In the present invention, specifically in implementation, for the high-side contactor KL1, before the high-voltage power-on and after the high-voltage power-off of the power battery system, its normal state should be: the coil power supply of the high-side contactor KL1 is not energized, the signal KLC at the input terminal KLC of the coil startup detection circuit 300 is at a low potential (because at this time the coil of the high-side contactor KL1 is disconnected from the power supply, so the coil power supply signal provided by the external coil drive circuit is a low-potential coil power supply signal, that is, a low-potential KLC signal), the contact of the high-side contactor KL1 is disconnected, the KC1 switch control signal (a low-level signal in the present invention) output by the output terminal KC1 of the BMS main control chip 400 controls the switch K1 to be disconnected. Therefore, the voltage HVP at the first input terminal (used to connect the positive terminal HVP) of the contact detection input circuit 100 is 0V, the optocoupler Q1 is cut off, so that the switching transistor Q2 and the switching transistor Q3 are also cut off, the output terminal B of the contact detection output circuit 200 is pulled low to a low level by the resistor R7, and the output terminal A of the coil startup detection circuit 300 is pulled low to a low level by the resistor R9.

[0111] It should be noted that during the adhesion detection before the high-voltage power-on of the power battery system, the switch K1 closes first; at the end of the adhesion detection after the high-voltage power-off, the switch K1 disconnects last; during the high-voltage power-on, the switch K1 is always closed.

[0112] It should be noted that at the end of the adhesion detection after the high-voltage power-off of the power battery system, the BMS main control chip 400 outputs a KC1 switch control signal (a low-level signal in the present invention) to the signal input terminal of the switch K1, thereby disconnecting the switch K1. The purpose is: when there is a contact adhesion fault, the contact input detection circuit 100 does not consume battery power.

[0113] The adhesion fault detection operation before high-voltage power-on and after high-voltage power-off of the power battery system is as follows: Before high-voltage power-on and after high-voltage power-off, the coil of the high-side contactor KL1 is not powered on, and the signal KLC at the input end KLC of the coil start detection circuit 300 is at a low potential (at this time, the state of the coil power signal provided by the external coil drive circuit is: a low-potential coil power signal). If the contact of the high-side contactor KL1 fails to disconnect due to adhesion at this time, the voltage HVP at the first input end (used to connect the positive terminal HVP) of the contact detection input circuit 100 will still be equal to the battery positive voltage B+ in the power battery system. After being divided by the resistors R1 and R2, the voltage detection terminal V1 between the resistors R1 and R2 remains at a high potential, thereby continuously conducting the optocoupler Q1, keeping the switching transistor 2 and the switching transistor Q3 in a conducting state. The contact detection signal B at the output end B of the contact detection output circuit 200 remains at a high level, while the coil start detection signal A at the output end A of the coil start detection circuit 300 is at a low level. At this time, the BMS main control chip 400 determines that the contact of the high-side contactor KL1 is adhered. After recording the adhesion fault, it outputs a low-level switch control signal KC1 to disconnect the switch K1, and the adhesion detection ends.

[0114] It should be noted that when the BMS main control chip 400 determines that there is an adhesion fault in the contact of the high-side contactor KL1, it can alarm the existing in-vehicle electronic control system located outside, so as to timely remind the operator to manually disconnect the high-voltage circuit before maintenance.

[0115] The detection operation of whether the high-side contactor is activated during high-voltage power-on of the power battery system is as follows: During high-voltage power-on, the coil of the contactor KL1 is powered on, and the signal KLC at the input end KLC of the coil start detection circuit 300 is at a high potential (at this time, the state of the coil power signal provided by the external coil drive circuit is: a high-potential coil power signal). The contact of the high-side contactor KL1 is attracted. The BMS main control chip outputs a high-level KC1 switch control signal KC1 to the signal input end of the switch K1 in the contact detection input circuit 100, thereby controlling the closing of the switch K1. The voltage HVP at the first input end (i.e., the input end HVP) of the contact detection input circuit 100 is equal to the battery voltage B+, making the optocoupler Q1, the switching transistor Q2, and the switching transistor Q3 all conduct. Then, both the coil start detection signal A at the output end A of the coil start detection circuit and the contact detection signal B at the output end B of the contact detection output circuit are at a high level. At this time, the BMS main control chip 400 determines that the high-side contactor KL1 has been activated at high voltage, and the high-voltage power-on is successful. Otherwise, it is determined that the high-side contactor KL1 has not been activated at high voltage, and the high-voltage power-on fails.

[0116] It should be noted that when the BMS master chip 400 determines that the high-voltage activated high-side contactor KL1 is not activated, it can alarm the existing in-vehicle electronic control system located outside and inform that the high-voltage power-on fails.

[0117] In the present invention, specifically in implementation, it should be noted that the BMS master chip 400 can adopt the commonly used brands, series and models at present, such as the MC9S12 series of NXP, the TC265 of the TC2 series of Infineon, etc. The model of the BMS master chip 400 is not within the protection scope of the present invention.

[0118] In summary, compared with the prior art, the adhesion fault detection circuit of the high-side contactor provided by the present invention can accurately determine whether the contacts of the high-side contactor are adhered without manual troubleshooting, which can significantly improve the detection efficiency and has great practical significance.

[0119] In addition, the adhesion fault detection circuit of the high-side contactor provided by the present invention has a scientific hardware circuit design, does not occupy additional port resources of the BMS master chip. Since it does not directly detect high voltage, the electronic components are commonly used models, which are easy to select. Moreover, the circuit board occupies a small space and the design cost is very low. It is a technical solution that is easy to select components and has a low cost. Therefore, the technical solution of the present invention has strong practical value and market promotion value.

[0120] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An adhesion fault detection circuit for a high-side contactor, characterized in that, It includes a contact detection input circuit (100), a contact detection output circuit (200), a coil start detection circuit (300), and a BMS main control chip (400); among them, for the contact detection input circuit (100), its first input terminal is connected to the positive terminal HVP of the power battery system, and is used to receive the positive terminal voltage of the high N series battery pack in the power battery system; the positive terminal HVP of the power battery system is connected to the positive terminal B+ of the high N series battery pack in the power battery system through the high-side contactor KL1; the high N series battery pack is multiple series-connected single cells in the power battery system close to the high-side contactor KL1; among them, for the contact detection input circuit (100), its second input terminal is connected to the negative terminal BH- of the high N series battery pack in the power battery system, and is used to receive the negative terminal voltage of the power battery system; among them, for the contact detection input circuit (100), its third input terminal is connected to the output terminal KC1 of the BMS main control chip, and is used to receive and execute the switch control signal KC1 output by the BMS main control chip; among them, for the contact detection input circuit (100), its output terminal is respectively connected to the input terminal of the contact detection output circuit (200) and the second input terminal of the coil start detection circuit (300), and is used to control the on and off of these two circuits, namely the contact detection output circuit (200) and the coil start detection circuit (300); for the contact detection output circuit (200), its output terminal B is connected to the first input terminal of the BMS main control chip (400), and is used to output the contact detection signal B to the BMS main control chip (400); for the coil start detection circuit (300), its first input terminal KLC is connected to an external coil drive circuit, and is used to receive the coil start signal sent by the external coil drive circuit; for the coil start detection circuit (300), its output terminal A is connected to the second input terminal of the BMS main control chip (400), and is used to output the coil start detection signal A to the BMS main control chip (400); the BMS main control chip (400) is used to receive the contact detection signal B conveyed by the contact detection output circuit (200) and the coil start detection signal A output by the coil start detection circuit (300). When before high-voltage power-on or after high-voltage power-off, if the contact detection signal B at the output terminal B of the contact detection output circuit (200) is at a high level, while the coil start detection signal A at the output terminal A of the coil start detection circuit (300) is at a low level, then it is determined that there is an adhesion fault in the high-side contactor KL1; the contact detection input circuit (100) includes a resistor R1, a resistor R2, a switch K1, a capacitor C1, a resistor R3, a diode D1, an optocoupler Q1, a resistor R4, and a resistor R6, where: the negative terminal of the high N series battery pack in the power battery system is connected to one end of the switch K1; this end of the switch K1 serves as the second input terminal of the contact detection input circuit (100); the first pin of the resistor R1 serves as the first input terminal of the contact detection input circuit (100) and is connected to the positive terminal HVP of the power battery system;The second pin of resistor R1 is respectively connected to the first pin of resistor R2, the first pin of capacitor C1, and the first pin of resistor R3; the second pin of resistor R2 is connected to the other end of switch K1; the second pin of resistor R2 is also respectively connected to the second pin of capacitor C1, optocoupler Q1, and the anode of diode D1; among them, the signal input end of switch K1 serves as the third input end of the contact detection input loop (100) and is connected to the output end KC1 of the BMS main control chip; the second pin of resistor R3 is respectively connected to the first pin of optocoupler Q1 and the cathode of diode D1; the third pin of optocoupler Q1 is connected to the second pin of resistor R4; the fourth pin of optocoupler Q1 is grounded; the first pin of resistor R4 is respectively connected to the second pin of resistor R6 and the base of switch transistor Q2; the first pin of resistor R6 is respectively connected to the second pin of resistor R5 and the emitter of switch transistor Q2; the BMS main control chip (400) is further configured to, when it is determined that there is an adhesion fault in the high-side contactor KL1 before high-voltage power-on or after high-voltage power-off, send a low-level switch control signal KC1 to the signal input end of switch K1 in the contact detection input loop (100) to turn off the switch K1, so that the adhesion detection is ended.

2. The adhesion fault detection circuit of the high-side contactor according to claim 1, characterized in that The BMS master control chip (400) is also configured to, when high voltage is powered on, determine that the high-side contactor KL1 has been activated by high voltage if the contact detection signal B at the output end B of the contact detection output circuit (200) and the coil start detection signal A at the output end A of the coil start detection circuit (300) are both at high level; otherwise, determine that the high-side contactor KL1 has not been activated by high voltage.

3. The adhesion fault detection circuit of the high-side contactor according to claim 1, characterized in that, The contact detection output circuit (200) includes: a resistor R5, a switching transistor Q2, and a resistor R7, where: the first pin of the resistor R5 is connected to an external DC power supply of 5V; the collector of the switching transistor Q2 is respectively connected to the output end B of the contact detection output circuit (200) and the first pin of the resistor R7; the second pin of the resistor R7 is grounded.

4. The adhesion fault detection circuit of the high-side contactor according to claim 3, characterized in that The coil start detection circuit (300) includes: a resistor R8, a switching transistor Q3, and a resistor R9, where: the base of the switching transistor Q3 serves as the second input end of the coil start detection circuit (300) and is connected to the third pin of the optocoupler Q1; the emitter of the switching transistor Q3 is connected to the second pin of the resistor R8; the first pin of the resistor R8 serves as the first input end of the coil start detection circuit (300) and is used to connect to an external coil drive circuit for receiving a coil start signal sent by the external coil drive circuit; the collector of the switching transistor Q3 is respectively connected to the output end A of the coil start detection circuit (300) and the first pin of the resistor R9; the second pin of the resistor R9 is grounded.

5. The adhesion fault detection circuit of the high-side contactor according to claim 1, characterized in that Before the high voltage of the power battery system is powered on and after the high voltage is powered off, the BMS master control chip (400) determines whether there is a contact sticking fault in the high-side contactor KL1 according to the combined logic of the coil start detection signal A output from the output end A of the coil start detection circuit (300) and the contact detection signal B output from the output end B of the contact detection output circuit (200). The specific judgment conditions are as follows: First, when both the coil start detection signal A and the contact detection signal B are at low level, it is determined that the contacts of the high-side contactor KL1 are not stuck; Second, when the coil start detection signal A is at low level and the contact detection signal B is at high level, it is determined that the contacts of the high-side contactor KL1 are stuck.

6. The adhesion fault detection circuit of the high-side contactor according to claim 1, characterized in that, When the high voltage of the power battery system is powered on, the BMS master control chip (400) determines whether the high-side contactor KL1 has been activated by high voltage according to the combined logic of the detection signal B output from the output end B of the contact detection output circuit (200) and the coil start detection signal A output from the output end A of the coil start detection circuit (300). The judgment conditions are as follows: First, when both the coil start detection signal A and the contact detection signal B are at high level, it is determined that the high-side contactor KL1 has been activated by high voltage; Second, when both the coil start detection signal A and the contact detection signal B are at low level, it is determined that the high-side contactor KL1 has not been activated by high voltage.

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