A relay sticking detection circuit

Abstract

The utility model relates to a kind of relay sticking detection circuit, comprising: first interface, second interface, third interface and fourth interface;Power supply, anode connects first interface;Peak absorption subcircuit, between the negative pole of second interface and power supply;Optocoupler, anode connects second interface;Impedance matching and protection subcircuit, between the negative pole of optocoupler and the negative pole of power supply;Detection output subcircuit, connecting collector and emitter of optocoupler, third interface and fourth interface.The utility model is more simple in the way of directly collecting relay two contact rear-end voltage, the reliability of detection is also higher, and the electronic components required by detection circuit are less, reduce cost;In addition, the utility model uses the way of optocoupler detection, the main loop and detection loop are isolated, more safe.

Description

Technical Field

[0001] This utility model relates to the field of relay testing, specifically to a relay adhesion detection circuit. Background Technology

[0002] With the rapid progress and development of the new energy vehicle industry, relays are widely used in automotive power supply systems. As a switching device, they control the connection and disconnection of current. However, during use, factors such as control strategies can lead to relay overload, resulting in relay sticking. Relay sticking refers to the phenomenon where a relay, in its closed state, cannot open properly due to adhesion between its contacts. This can lead to circuit abnormalities, equipment damage, or even safety accidents. Existing relay sticking detection methods compare the high-voltage states at both ends of the relay to confirm whether it is sticking. Diagnosing the sticking of any relay in the system requires collecting and comparing the two high-voltage signals at both ends of the relay. Therefore, the more relays there are, the more high-voltage signals need to be collected, requiring more acquisition circuits and increasing the cost of the solution. Thus, existing relay sticking detection methods suffer from problems such as complex circuitry, high detection costs, and cumbersome detection logic. Utility Model Content

[0003] This utility model provides a relay adhesion detection circuit to solve at least one of the above-mentioned technical problems.

[0004] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: A relay adhesion detection circuit, comprising:

[0005] First interface, second interface, third interface, and fourth interface;

[0006] Power supply, with the positive terminal connected to the first interface;

[0007] A peak absorption sub-circuit is connected between the second interface and the negative terminal of the power supply;

[0008] The optocoupler's positive terminal is connected to the second interface;

[0009] An impedance matching and protection sub-circuit is connected between the negative terminal of the optocoupler and the negative terminal of the power supply.

[0010] The detection output sub-circuit connects the collector and emitter of the optocoupler, the third interface, and the fourth interface;

[0011] When the management system is used to detect adhesion of the relay under test, the two contacts of the relay under test are connected to the first interface and the second interface respectively. The third interface is connected to the management system to obtain the power supply voltage signal from the management system. The fourth interface is connected to the management system to transmit the detection output signal to the management system, and then the management system determines whether the relay under test is stuck.

[0012] Based on the above technical solution, the present invention can be further improved as follows.

[0013] Furthermore, the peak absorption sub-circuit includes a first diode, a first resistor, and a first capacitor; the first resistor and the first capacitor are connected in parallel and then connected in series with the first diode between the second interface and the negative terminal of the power supply.

[0014] Furthermore, the impedance matching and protection sub-circuit includes a second diode and a second resistor, which are connected in series between the negative terminal of the optocoupler and the negative terminal of the power supply.

[0015] Furthermore, the detection output sub-circuit includes a third resistor and a second capacitor; the third resistor is connected between the third interface and the collector of the optocoupler, the second capacitor is connected between the collector of the optocoupler and the emitter of the optocoupler, the emitter of the optocoupler is grounded, and one end of the third resistor connected to the collector of the optocoupler and one end of the second capacitor connected to the collector of the optocoupler are both connected to the fourth interface.

[0016] Furthermore, the management system is specifically a battery management system.

[0017] The beneficial effects of this utility model are: the method of directly collecting the voltage at the rear end of the two contacts of the relay in the relay adhesion detection circuit of this utility model is simpler, the detection reliability is higher, and fewer electronic components are required for the detection circuit, thus reducing costs; in addition, this utility model adopts an optocoupler detection method, which isolates the main circuit and the detection circuit, making it safer. Attached Figure Description

[0018] Figure 1 This is a structural block diagram of a relay adhesion detection circuit according to the present invention;

[0019] Figure 2 This is a schematic diagram of a relay adhesion detection circuit according to the present invention. Detailed Implementation

[0020] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0021] like Figure 1 As shown, a relay adhesion detection circuit includes:

[0022] First interface J1, second interface J2, third interface J3 and fourth interface J4;

[0023] Power supply E, with its positive terminal connected to the first interface J1;

[0024] Peak absorption sub-circuit 1 is connected between the second interface J2 and the negative terminal of the power supply E;

[0025] Optical coupler U, positive terminal connected to the second interface J2;

[0026] Impedance matching and protection sub-circuit 2 is connected between the negative terminal of the optocoupler U and the negative terminal of the power supply E;

[0027] The detection output sub-circuit 3 is connected to the collector and emitter of the optocoupler U, the third interface J3, and the fourth interface J4;

[0028] When the management system 4 is used to detect adhesion of the relay K to be tested, the two contacts of the relay K to be tested are connected to the first interface J1 and the second interface J2 respectively. The third interface J3 is connected to the management system 4 to obtain the power supply voltage signal VCC from the management system 4. The fourth interface J4 is connected to the management system 4 to transmit the detection output signal to the management system 4, and then the management system 4 determines whether the relay K to be tested is stuck.

[0029] In some embodiments, such as Figure 2 As shown: The peak absorption sub-circuit 1 includes a first diode D1, a first resistor R1 and a first capacitor C1; the first resistor R1 and the first capacitor C1 are connected in parallel and then connected in series with the first diode D1 between the second interface J2 and the negative terminal of the power supply E.

[0030] Specifically, the first resistor R1 and the first capacitor C1 are connected in parallel and then connected in series with the first diode D1 between the second interface J2 and the negative terminal of the power supply E. This can prevent the current from flowing in reverse and absorb the peak voltage in the circuit, protecting the components in the circuit from damage.

[0031] In some embodiments, such as Figure 2 As shown: The impedance matching and protection sub-circuit 2 includes a second diode D2 and a second resistor R2, which are connected in series between the negative terminal of the optocoupler U and the negative terminal of the power supply E.

[0032] Specifically, the second diode D2 and the second resistor R2 are connected in series between the negative terminal of the optocoupler U and the negative terminal of the power supply E. This can effectively adjust the impedance of the input terminal, enabling better impedance matching between the input signal source and the optocoupler, thereby optimizing the signal transmission effect. In addition, the input terminal of the optocoupler usually has a high input impedance. By connecting the series resistor, the voltage signal can be more stably distributed throughout the circuit, thereby reducing the impact of noise from the input power supply on the circuit.

[0033] In some embodiments, such as Figure 2 As shown: The detection output sub-circuit 3 includes a third resistor R3 and a second capacitor C2; the third resistor R3 is connected between the third interface J3 and the collector of the optocoupler U, the second capacitor C2 is connected between the collector of the optocoupler U and the emitter of the optocoupler U, the emitter of the optocoupler U is grounded, and one end of the third resistor R3 connected to the collector of the optocoupler U and one end of the second capacitor C2 connected to the collector of the optocoupler U are both connected to the fourth interface J4.

[0034] Specifically, the second capacitor C2 can reduce the load effect and improve the stability and operating efficiency of the circuit.

[0035] In some embodiments, the management system 4 is specifically a battery management system (BMS).

[0036] The process of detecting relay adhesion using the relay adhesion detection circuit of this utility model is as follows: First, the relay to be tested, K, is controlled to be in the open state. Then, the signal at the fourth interface J4 at the rear end of the optocoupler is detected. Finally, it can be determined whether the relay to be tested, K, is stuck. Specifically, taking the relay to be tested, K, in the battery pack of an electric vehicle as an example, the vehicle first supplies power to the battery management system (BMS) controller to start it working (the relay to be tested, K, is controlled by the BMS). The BMS detects whether the relay to be tested, K, is stuck by checking whether it receives a signal from the fourth interface J4 at the rear end of the optocoupler. If the BMS receives a signal from the optocoupler, it determines that the relay to be tested, K, is stuck; otherwise, it is not stuck. Because the relay to be tested, K, is in the open state due to the lack of driving voltage during the adhesion detection process, no current flows through the optocoupler U, and the transistor at the rear end of the optocoupler is in the open state. Therefore, the rear end of the optocoupler cannot detect a signal, and the BMS cannot receive a signal from the optocoupler, so it determines that the relay to be tested, K, is in the open state. If the relay K under test is in a stuck state, both ends of the relay K will be in a continuous conducting state. When the BMS starts the stuck state detection, because the relay K is conducting, the optocoupler U will also be in a continuous conducting state due to the current flowing through it. Therefore, the back end of the optocoupler U can detect the signal, and the BMS can receive the signal sent by the optocoupler U. Thus, it can be determined that the relay K under test is in a stuck state. The presence of a signal can be detected by performing two tests. First, a test is performed, and after a 100ms interval, a second test can be performed. If a signal is sent in both tests, it can be confirmed that the relay is stuck. The BMS will then report a main relay stuck state fault and send a fault code.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A relay adhesion detection circuit, characterized in that, include: First interface, second interface, third interface, and fourth interface; Power supply, with the positive terminal connected to the first interface; A peak absorption sub-circuit is connected between the second interface and the negative terminal of the power supply; an optocoupler has its positive terminal connected to the second interface; An impedance matching and protection sub-circuit is connected between the negative terminal of the optocoupler and the negative terminal of the power supply. The detection output sub-circuit connects the collector and emitter of the optocoupler, the third interface, and the fourth interface; When the management system is used to detect adhesion of the relay under test, the two contacts of the relay under test are connected to the first interface and the second interface respectively. The third interface is connected to the management system to obtain the power supply voltage signal from the management system. The fourth interface is connected to the management system to transmit the detection output signal to the management system, and then the management system determines whether the relay under test is stuck.

2. The relay adhesion detection circuit according to claim 1, characterized in that, The peak absorption sub-circuit includes a first diode, a first resistor, and a first capacitor; the first resistor and the first capacitor are connected in parallel and then connected in series with the first diode between the second interface and the negative terminal of the power supply.

3. The relay adhesion detection circuit according to claim 1, characterized in that, The impedance matching and protection sub-circuit includes a second diode and a second resistor, which are connected in series between the negative terminal of the optocoupler and the negative terminal of the power supply.

4. The relay adhesion detection circuit according to claim 1, characterized in that, The detection output sub-circuit includes a third resistor and a second capacitor; the third resistor is connected between the third interface and the collector of the optocoupler, the second capacitor is connected between the collector of the optocoupler and the emitter of the optocoupler, the emitter of the optocoupler is grounded, and one end of the third resistor connected to the collector of the optocoupler and one end of the second capacitor connected to the collector of the optocoupler are both connected to the fourth interface.

5. The relay adhesion detection circuit according to claim 1, characterized in that, The management system is specifically a battery management system.

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