A relay contact state detection circuit, a vehicle, and a high-voltage power distribution system

Abstract

The present invention belongs to the technical field of vehicles, and provides a vehicle, a high-voltage power distribution system and a relay contact state detection circuit thereof. In the present invention, by adopting a relay contact state detection circuit including a control circuit, a first switch circuit, a detection circuit and a second switch circuit, the first switch circuit is controlled by the control circuit and the second switch circuit to connect or disconnect the path between the relay and the rear-end detection circuit, avoiding the impact of the back electromotive force generated during the closing or opening of the relay on the rear-end low-voltage detection circuit, and thus solving the problem existing in the traditional relay contact state detection circuit that the relay generates a back electromotive force when closing or opening, and this back electromotive force will impact the rear-end low-voltage detection circuit, resulting in circuit failure.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicles, and particularly relates to a relay contact state detection circuit, a vehicle, and a high-voltage power distribution system. Background Art

[0002] In an electric vehicle, a high-voltage power distribution system is a switching device between a high-voltage battery and high-voltage components (main drive, oil pump, air pump, DCDC, charger, etc.). A relay is a key device for achieving high-voltage control through low voltage. The quality of the relay affects the effectiveness of the high-voltage power distribution system, and further affects the control effectiveness of the vehicle. That is, when a relay contact fails, the high-voltage system of the whole vehicle loses effective control, resulting in potential safety hazards during driving.

[0003] To eliminate the safety hazards caused by relay contact failures, it is necessary to detect the state of the relay contacts in the high-voltage power distribution system of an electric vehicle to determine whether the relay has failed. Currently, the prior art mainly provides an auxiliary power supply to the relay and collects the voltage at the rear end of the relay and compares it with the battery voltage to identify whether the relay contacts are closed or open. Then, the relay contact state is further compared with the relay control signal to determine whether the relay contacts are stuck or failed.

[0004] However, a back electromotive force is generated when the relay closes or opens, and this back electromotive force will impact the low-voltage detection circuit at the rear end, causing the circuit to fail, and further resulting in incorrect judgment of the relay contact state, thus affecting the safety of the whole vehicle system. Summary of the Invention

[0005] The purpose of the present invention is to provide a relay contact state detection circuit, a vehicle, and a high-voltage power distribution system, aiming to solve the problem that the traditional relay contact state detection circuit has a back electromotive force generated when the relay closes or opens, and this back electromotive force will impact the low-voltage detection circuit at the rear end, causing the circuit to fail.

[0006] The present invention is implemented as follows. A relay contact state detection circuit is connected to a relay. The relay contact state detection circuit includes: a control circuit, a first switch circuit, a detection circuit, and a second switch circuit;

[0007] The control circuit is connected to the detection circuit and the second switch circuit, and is configured to generate a relay control signal to control the relay to close or open, generate a detection start signal after the relay closes or opens for a preset time, and obtain the relay state according to the detection signal and the relay control information; the relay control signal carries the relay control information;

[0008] The second switch circuit is connected to the first switch circuit and is configured to generate a first switch control signal according to the detection start signal;

[0009] The first switch circuit is connected to the detection circuit and is configured to generate a second switch control signal according to the first switch control signal;

[0010] The detection circuit is configured to generate a detection signal according to the second switch control signal.

[0011] Another object of the present invention is to provide a high-voltage power distribution system, and the high-voltage power distribution system includes the above-mentioned relay contact state detection circuit.

[0012] Still another object of the present invention is to provide a vehicle, and the vehicle includes the above-mentioned relay contact state detection circuit.

[0013] In the present invention, by adopting a relay contact state detection circuit including a control circuit, a first switch circuit, a detection circuit, and a second switch circuit, the first switch circuit is controlled by the control circuit and the second switch circuit to connect or disconnect the path between the relay and the backend detection circuit, avoiding the impact of the back electromotive force generated during the closing or opening of the relay on the backend low-voltage detection circuit, and thus solving the problem existing in the traditional relay contact state detection circuit that the relay generates a back electromotive force when closing or opening, and this back electromotive force will impact the backend low-voltage detection circuit, resulting in circuit failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic module structure diagram of a relay contact state detection circuit provided by an embodiment of the present invention;

[0015] Figure 2 is a schematic module structure diagram of a relay contact state detection circuit provided by another embodiment of the present invention;

[0016] Figure 3 is a schematic circuit structure diagram of a relay contact state detection circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] 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 accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] The implementation of the present invention will be described in detail below with reference to specific drawings:

[0019] Figure 1The module structure of the relay contact state detection circuit 10 provided by an embodiment of the present invention is shown. For ease of description, only the parts related to this embodiment are shown and are described in detail as follows:

[0020] As Figure 1 shown, the relay contact state detection circuit 10 provided by the embodiment of the present invention is connected to the relay 20, and includes a control circuit 101, a first switch circuit 102, a detection circuit 103, and a second switch circuit 104.

[0021] Among them, the control circuit 101 is connected to the detection circuit 103 and the second switch circuit 104, and is configured to generate a relay control signal to control the relay to close or open, generate a detection start signal after the relay closes or opens for a preset time, and obtain the relay state according to the detection signal and the relay control information; the relay control signal carries the relay control information;

[0022] The second switch circuit 104 is connected to the first switch circuit 102, and is configured to generate a first switch control signal according to the detection start signal;

[0023] The first switch circuit 102 is connected to the detection circuit 103; and is configured to generate a second switch control signal according to the first switch control signal;

[0024] The detection circuit 103 is configured to generate a detection signal according to the second switch control signal.

[0025] In specific implementation, the preset time can be set as needed, that is, the setting principle of the preset time is that when the relay is disconnected or closed, the time spent discharging the back electromotive force generated by the instantaneous closing or opening is used as the preset time; in addition, in this embodiment, the control circuit 101 can be implemented by a processor with digital logic processing capabilities such as a microcontroller or a field programmable gate array.

[0026] In addition, the relay control signal is a switch control signal for controlling the relay to close or open, and the relay control information carried by the relay control signal is control information for controlling the relay and can represent the actual closed state or open state of the relay. The detection start signal is a start signal for detecting the relay contact state, and the detection signal is a signal corresponding to the closed state or open state of the relay detected by the detection circuit 103 and fed back to the control circuit 101. When the control circuit 101 obtains the above two different switch states of the relay 20, the contact state of the relay 20 can be confirmed according to the above two different switch states.

[0027] As described above, when the relay control information is to control the relay to close, and the detection signal generated by the detection circuit 103 is a relay open signal, the relay state obtained by the control circuit 101 is that the relay contact fails. That is, if the actual state of the relay 20 obtained by the control circuit 101 is closed, and the state of the relay feedback by the detection circuit 103 to the control circuit 101 is open, then it proves that the contact of the relay 20 fails at this time. When the relay control information is to control the relay to open, and the detection signal generated by the detection circuit 103 is a relay close signal, the relay state obtained by the control circuit 101 is that the relay contacts are stuck. That is, if the actual state of the relay 20 obtained by the control circuit 101 is open, and the state of the relay feedback by the detection circuit 103 to the control circuit 101 is closed, then it proves that the contacts of the relay 20 are stuck at this time. That is to say, the contact state of the relay 20 is a stuck state at this time.

[0028] In this embodiment, by adopting the relay contact state detection circuit 10 including the control circuit 101, the first switch circuit 102, the detection circuit 103 and the second switch circuit 104, the first switch circuit 102 is controlled by the control circuit 101 and the second switch circuit 104 to connect or disconnect the path between the relay and the backend detection circuit 103, avoiding the impact of the back electromotive force generated when the relay closes or opens on the backend low-voltage detection circuit, and thus preventing the misjudgment of the relay contact state, improving the safety of the vehicle system.

[0029] Furthermore, as an implementation manner of the present invention, as Figure 2 shown, the second switch circuit 104 includes: a switch component 104a and an isolation component 104b.

[0030] Among them, the switch component 104a is connected to the isolation component 104b and the control circuit 101, and is configured to generate a third switch control signal according to the detection start signal;

[0031] The isolation component 104b is connected to the first switch circuit 102, and is configured to generate a first switch control signal according to the third switch control signal.

[0032] Specifically, the switch component 104a receives the detection start signal, generates a third control signal according to the detection start signal, and outputs the third control signal to the isolation component 104b, so that the isolation component 104b generates a first switch control signal according to the third switch control signal, and controls the on / off of the first switch circuit 102 according to the first switch control signal.

[0033] In this embodiment, by providing a second switch circuit 104 including a switch component 104a and an isolation component 104b in the relay contact state detection circuit 10, the second switch circuit 104 and the control circuit 101 act together to control the first switch circuit 102 to connect or disconnect the path between the relay 20 and the detection circuit 103, avoiding damage to the low-voltage detection circuit at the rear end, i.e., the detection circuit 103, caused by the high-voltage impact generated when the relay contacts are turned on or off. Furthermore, the relay contact state detection circuit is not damaged, improving the accuracy of relay contact state detection, thereby enhancing the safety performance of the vehicle's high-voltage system and ensuring vehicle safety.

[0034] Further, as an implementation manner of the present invention, as Figure 3 shown, the switch component 104a includes a first resistor R1, a first capacitor C1, and a first switching element Q1.

[0035] Among them, the first end of the first resistor R1 is the input end of the detection start signal K2-EN of the switch component 104a. The second end of the first resistor R1 is connected to the first end of the first capacitor C1 and the base terminal of the first triode Q1. The emitter of the first triode Q1 is the output end of the third switch control signal of the switch component 104a. The collector of the first triode Q1 and the second end of the first capacitor C1 are commonly connected to the power ground.

[0036] Specifically, the first triode Q1 is implemented by an N-type triode; it should be noted that in other embodiments, the switching device of the first triode Q1 can also be implemented by other switching devices with a switching function, such as an N-type MOS transistor, which is not limited herein.

[0037] Further, as an implementation manner of the present invention, as Figure 3 shown, the isolation component 104b includes a second resistor R2, a third resistor R3, a second capacitor C2, and a first optocoupler U1.

[0038] Among them, the first end of the second resistor R2 is connected to a first power supply, and the first power supply can output a working voltage of 5V, for example. The second end of the second resistor R2 is connected to the positive electrode 1 of the first optocoupler U1. The negative electrode 2 of the first optocoupler U1 is the input end of the third switch control signal of the isolation component 104b. The collector 3 of the first optocoupler U1 and the second end of the second capacitor C2 together constitute the output end of the first switch control signal of the isolation component 104b. The first end of the second capacitor C2 is connected to the second end of the third resistor R3, and the first end of the third resistor R3 is connected to the first power supply.

[0039] Further, as an implementation manner of the present invention, as Figure 3As shown in the figure, the first switch circuit 102 includes a field effect transistor Q2, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a first diode D1.

[0040] Specifically, the anode of the first diode D1 is connected to the relay 20, the cathode of the first diode D1 is connected to the first end of the fourth resistor R4, the second end of the fourth resistor R4 is connected to the first end of the fifth resistor R5, the second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is connected to the source of the field effect transistor Q2, the gate of the field effect transistor Q2 is the first switch control signal input terminal of the first switch circuit 102, and the drain of the field effect transistor Q2 is the second switch control signal output terminal of the first switch circuit 102.

[0041] In specific implementation, the field effect transistor Q2 is implemented by a P-type MOS transistor; it should be noted that in other embodiments, the switching device of the field effect transistor Q2 can also be implemented by other switching devices with a switching function, such as a P-type triode, which is not limited here.

[0042] Further, as an implementation manner of the present invention, the detection circuit 103 includes a seventh resistor R7, an eighth resistor R8, and a second optocoupler U2.

[0043] Among them, the first end of the seventh resistor R7 is connected to the first switch circuit 102 and the anode 1 of the second optocoupler U2, the second end of the seventh resistor R7 and the cathode 2 of the second optocoupler U2 are both grounded, the collector 3 of the second optocoupler U2 is grounded, the emitter 4 of the second optocoupler U2 and the first end of the eighth resistor R8 together constitute the output terminal of the detection signal of the detection circuit 103, and the second end of the eighth resistor R8 is connected to the first power supply.

[0044] It should be noted that in this embodiment, the drain of the field effect transistor Q2 of the first switch circuit 102 is connected to the first end of the seventh resistor R7 and the anode 1 of the second optocoupler U2, while in other implementation manners, the drain of the field effect transistor Q2 of the first switch circuit 102 is directly connected to the power ground.

[0045] Next, taking Figure 3 the circuit shown in the figure as an example, the working principle of the relay contact state detection circuit 10 provided by the present invention will be specifically described in detail as follows:

[0046] As shown in Figure 3As shown, the control circuit 101 generates a relay control signal and controls the relay 20 to close according to this relay control signal. At this time, the control circuit 101 obtains the relay control information carried by the relay control signal, that is, controls the relay to close, and after delaying for a preset time, sends a detection start signal K2-EN to the switch assembly 104a. After receiving the detection start signal K2-EN, the switch assembly 104a controls the first triode Q1 to conduct. When the first triode Q1 conducts, it pulls down the control terminal voltage of the field effect transistor Q2 through the first optocoupler U1 to control the field effect transistor Q2 to conduct. When the field effect transistor Q2 conducts, the front-end voltage connected to the relay 20 flows through the diode D1, resistor R4, resistor R5, resistor R6, and the field effect transistor Q2 into the second optocoupler U2, causing the primary side of the second optocoupler U2 to be connected and the secondary side to be pulled down, and then outputting a relay closed signal (a detection signal of a low-level signal) to the control circuit 101, and determining that the contacts of the relay 20 are normal according to the relay control information for controlling the relay to close and the relay closed signal (low-level detection signal) indicating the relay is closed; in addition, when the front-end voltage connected to the relay 20 flows through the diode D1, resistor R4, resistor R5, resistor R6, and the field effect transistor Q2 into the second optocoupler U2, if the second optocoupler U2 does not form a path, and then when the detection circuit 103 outputs a relay open signal (a detection signal of a high-level signal) to the control circuit 101, the control circuit 101 determines that the contact state of the relay 20 fails according to the relay control information for controlling the relay to close and the relay open signal (high-level detection signal) indicating the relay is open, that is, the relay has a contact failure fault.

[0047] Further, the control circuit 101 generates a relay control signal and controls the relay 20 to disconnect according to the relay control signal. At this time, the control circuit 101 obtains the relay control information carried by the relay control signal, that is, controls the relay to disconnect, and after a preset time delay, sends a detection start signal K2-EN to the switch assembly 104a. After receiving the detection start signal K2-EN, the switch assembly 104a controls the first triode Q1 to conduct. When the first triode Q1 conducts, it pulls down the control terminal voltage of the field effect transistor Q2 through the first optocoupler U1 to control the field effect transistor Q2 to conduct. When the field effect transistor Q2 conducts, since the front-end voltage connected to the relay 20 cannot flow through the diode D1, resistor R4, resistor R5, resistor R6, and the second switching element Q2 into the second optocoupler U2, the detection module 103 will directly feedback a relay disconnect signal (a high-level detection signal) to the control circuit 101, so that the control circuit 101 can identify that the relay 20 is currently in the disconnected state according to the feedback high-level detection signal, and determine that the contacts of the relay 20 are normal according to the relay control information for controlling the relay to disconnect and the relay disconnect signal (high-level detection signal) indicating the relay is disconnected; in addition, when the front-end voltage connected to the relay 20 flows through the diode D1, resistor R4, resistor R5, resistor R6, and the second switching element Q2 into the second optocoupler U2, the primary side of the second optocoupler U2 is turned on and the secondary side is pulled down, and then a relay closure signal (a low-level detection signal) is output to the control circuit 101. The control circuit 101 determines that the contacts of the relay 20 are stuck according to the relay control information for controlling the relay to disconnect and the relay closure signal (low-level detection signal) indicating the relay is closed, that is, the relay has a contact sticking fault.

[0048] In this embodiment, the present invention uses a switch circuit composed of simple devices such as resistors, capacitors, switching elements, and optocouplers. Under the control of the control circuit, the switch control circuit controls the switch circuit to conduct after the relay disconnects or conducts for a preset time, so as to facilitate the back-end detection circuit to detect the contact state of the relay. Furthermore, when the detection circuit detects, it can effectively avoid the spike voltage, prevent the high-voltage impact generated when the relay contacts are turned on or off from damaging the back-end low-voltage detection circuit, and thus will not damage the relay contact state detection circuit, improving the accuracy of the relay contact state detection, thereby improving the safety performance of the vehicle's high-voltage system, ensuring the safety of the vehicle, and having a simple circuit structure and low cost.

[0049] Further, the present invention also provides a high-voltage power distribution system, which includes a relay contact state detection circuit 10. It should be noted that, since the relay contact state detection circuit 10 in the high-voltage power distribution system provided by the embodiments of the present invention and Figures 1 to 3is the same as the relay contact state detection circuit 10 shown. Therefore, for the specific working principle of the relay contact state detection circuit 10 in the high-voltage power distribution system provided by the embodiments of the present invention, reference can be made to the foregoing description about Figures 1 to 3 and will not be elaborated here; in addition, for the specific structure and principle of the high-voltage power distribution system provided by the present invention, reference can be made to the prior art and will not be elaborated here.

[0050] Furthermore, the embodiments of the present invention further provide a vehicle, which includes a relay contact state detection circuit 10. It should be noted that since the relay contact state detection circuit 10 in the vehicle provided by the embodiments of the present invention and Figures 1 to 3 is the same as the relay contact state detection circuit 10 shown. Therefore, for the specific working principle of the relay contact state detection circuit 10 in the vehicle provided by the embodiments of the present invention, reference can be made to the foregoing description about Figures 1 to 3 and will not be elaborated here; in addition, for the specific structure and principle of the vehicle provided by the present invention, reference can be made to the prior art and will not be elaborated here.

[0051] In the present invention, by adopting a relay contact state detection circuit including a control circuit, a first switch circuit, a detection circuit, and a second switch circuit, the first switch circuit is controlled by the control circuit and the second switch circuit to connect or disconnect the path between the relay and the backend detection circuit, avoiding the impact of the back electromotive force generated during the closing or opening of the relay on the backend low-voltage detection circuit, and thus solving the problem existing in the traditional relay contact state detection circuit that the relay generates a back electromotive force when closing or opening, and this back electromotive force will impact the backend low-voltage detection circuit, causing circuit failure.

[0052] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A relay contact state detection circuit, connected to a relay, characterized in that, the relay contact state detection circuit includes: a control circuit, a first switch circuit, a detection circuit, and a second switch circuit; the control circuit is connected to the detection circuit and the second switch circuit, configured to generate a relay control signal to control the closing or opening of the relay, and generate a detection start signal after the relay is closed or opened for a preset time, and obtain the relay state according to the detection signal and the relay control information; the relay control signal carries the relay control information; the second switch circuit is connected to the first switch circuit, configured to generate a first switch control signal according to the detection start signal; the first switch circuit is connected to the detection circuit; configured to generate a second switch control signal according to the first switch control signal; the detection circuit is configured to generate a detection signal according to the second switch control signal; the second switch circuit includes: a switch component and an isolation component; the switch component is connected to the isolation component and the control circuit, configured to generate a third switch control signal according to the detection start signal; the isolation component is connected to the first switch circuit, configured to generate the first switch control signal according to the third switch control signal; wherein, when the relay control information is to control the relay to close, and the detection signal is a relay open signal, the relay state obtained by the control circuit is that the relay contact fails.

2. The relay contact state detection circuit according to claim 1, characterized in that, when the relay control information is to control the relay to open, and the detection signal is a relay close signal, the control circuit identifies the relay state as that the relay contact is stuck.

3. The relay contact state detection circuit according to any one of claims 1 to 2, characterized in that, the switch component includes a first resistor, a first capacitor, and a first triode; the first end of the first resistor is the input end of the detection start signal of the switch component, the second end of the first resistor is connected to the first end of the first capacitor and the base electrode end of the first triode, the emitter of the first triode is the output end of the third switch control signal of the switch component, and the collector of the first triode is connected to the second end of the first capacitor and grounded together.

4. The relay contact state detection circuit according to claim 1, characterized in that, the isolation component includes a second resistor, a third resistor, a second capacitor, and a first optocoupler; the first end of the second resistor is connected to a first power supply, the second end of the second resistor is connected to the positive electrode of the first optocoupler, the negative electrode of the first optocoupler is the input end of the third switch control signal of the isolation component, the collector of the first optocoupler and the second end of the second capacitor together constitute the output end of the first switch control signal of the isolation component, the first end of the second capacitor is connected to the second end of the third resistor, and the first end of the third resistor is connected to the first power supply.

5. The relay contact state detection circuit according to any one of claims 1 to 2, characterized in that, the first switch circuit includes a field effect transistor, a fourth resistor, a fifth resistor, a sixth resistor, and a first diode; the anode of the first diode is connected to the relay, the cathode of the first diode is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the first end of the fifth resistor, the second end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the source of the field effect transistor, the gate of the field effect transistor is the first switch control signal input end of the first switch circuit, and the drain of the field effect transistor is the second switch control signal output end of the first switch circuit.

6. The relay contact state detection circuit according to claim 4, characterized in that, the detection circuit includes a seventh resistor, an eighth resistor, and a second optocoupler; the first end of the seventh resistor is connected to the first switch circuit and the anode of the second optocoupler, the second end of the seventh resistor and the cathode of the second optocoupler are both grounded, the collector of the second optocoupler is grounded, the emitter of the second optocoupler and the first end of the eighth resistor together constitute the output end of the detection signal of the detection circuit, and the second end of the eighth resistor is connected to the first power supply.

7. A high-voltage power distribution system, characterized in that, the high-voltage power distribution system includes the relay contact state detection circuit according to any one of claims 1 to 6.

8. A vehicle, characterized in that, the vehicle includes the high-voltage power distribution system according to claim 7.

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