Relay control circuit and vehicle

Abstract

The embodiment of the utility model provides a relay control circuit and a vehicle, the relay control circuit comprises a voltage difference detection circuit and a coil control circuit, a first input end of the voltage difference detection circuit is connected with a first contact of a relay, and a second input end of the voltage difference detection circuit is connected with a second contact of the relay. The output end of the voltage difference detection circuit is connected with the input end of the coil control circuit, the first control end of the coil control circuit is connected with the first end of a coil of the relay, and the second control end of the coil control circuit is connected with the second end of the coil of the relay. When the voltage difference detection circuit detects that the voltage difference between the first contact of the relay and the second contact of the relay is larger than a set value, the output end of the voltage difference detection circuit outputs a high-level signal, and the high-level signal enables the coil control circuit to control the coil of the relay not to be excited, so that the relay is disconnected. When the voltage at two ends of the relay is too large, the relay is controlled to be disconnected through a hardware circuit, thereby reducing the risk of overcurrent adhesion of the relay.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a relay control circuit and a vehicle. Background Art

[0002] Relays are key components in the electrical systems of new energy vehicles, offering high-voltage, high-temperature, and shock-resistant capabilities, along with strong circuit-breaking capabilities. Relays are switching devices that can control larger currents with smaller currents and provide protection. Furthermore, in new energy vehicle applications, if improper control results in excessive voltage across the relay, a high current will be generated when the relay closes, potentially leading to overcurrent adhesion and failure. Utility Model Content

[0003] An embodiment of the present application provides a relay control circuit and a vehicle, which can control the relay to disconnect through a hardware circuit when the voltage across the relay is too large, thereby reducing the risk of relay overcurrent adhesion.

[0004] A first aspect of an embodiment of the present application provides a relay control circuit, comprising a pressure difference detection circuit and a coil control circuit, wherein a first input end of the pressure difference detection circuit is connected to a first contact of a relay, a second input end of the pressure difference detection circuit is connected to a second contact of the relay, an output end of the pressure difference detection circuit is connected to an input end of the coil control circuit, a first control end of the coil control circuit is connected to a first end of a coil of the relay, and a second control end of the coil control circuit is connected to a second end of the coil of the relay;

[0005] When the pressure difference detection circuit detects that the pressure difference between the first contact of the relay and the second contact of the relay is greater than a set value, the output end of the pressure difference detection circuit outputs a high-level signal, and the high-level signal causes the coil control circuit to control the coil of the relay to be unable to be energized, so that the relay is disconnected.

[0006] In an embodiment of the present application, when the pressure difference detection circuit detects that the pressure difference between the first contact of the relay and the second contact of the relay is greater than a set value, the output end of the pressure difference detection circuit outputs a high-level signal. The high-level signal prevents the coil control circuit from exciting the coil of the relay, so that the relay is disconnected. When the voltage across the relay is too large, the relay can be controlled to disconnect through the hardware circuit, thereby reducing the risk of overcurrent adhesion of the relay.

[0007] Optionally, when the pressure difference detection circuit detects that the pressure difference between the first contact of the relay and the second contact of the relay is less than the set value, the output end of the pressure difference detection circuit outputs a low-level signal, and the low-level signal enables the coil control circuit to allow the coil of the relay to be excited to close the relay.

[0008] In the embodiment of the present application, the relay can be allowed to close through the hardware circuit when the voltage across the relay is small, and the relay can be allowed to work normally when the voltage across the relay is small.

[0009] Optionally, the coil control circuit includes a first control circuit and a second control circuit, the first input end of the first control circuit is connected to the output end of the pressure difference detection circuit, the second input end of the first control circuit is connected to the signal output end of the control module, the first control end of the first control circuit is connected to the first control end of the second control circuit and the first end of the coil of the relay, the second control end of the second control circuit is connected to the second end of the coil of the relay, and the input end of the second control circuit is connected to the power supply end of the coil of the relay.

[0010] Optionally, the first control circuit includes: a first switch tube, a second switch tube, a first resistor, a second resistor, a third resistor and a fourth resistor, the first end of the first resistor is connected to the output end of the voltage difference detection circuit, the second end of the first resistor is connected to the first end of the second resistor and the control end of the first switch tube, the first end of the first switch tube is connected to the second end of the third resistor, the first end of the fourth resistor and the control end of the second switch tube, the first end of the second switch is connected to the first end of the coil of the relay, the first end of the third resistor is connected to the signal output end of the control module, and the second end of the first switch tube, the second end of the fourth resistor and the second end of the second switch tube are connected to the same potential.

[0011] Optionally, the second control circuit includes: a first diode and a fifth resistor, the positive electrode of the first diode is connected to the first end of the coil of the relay, the negative electrode of the first diode is connected to the second end of the coil of the relay and the second end of the fifth resistor, and the first end of the fifth resistor is connected to the power supply end of the coil of the relay.

[0012] Optionally, the pressure difference detection circuit includes: a first differential circuit, a second differential circuit, a second diode, a third diode and a trigger circuit, the first input end of the first differential circuit is connected to the first contact of the relay, the second input end of the first differential circuit is connected to the second contact of the relay, the output end of the first differential circuit is connected to the positive pole of the second diode, the first input end of the second differential circuit is connected to the second contact of the relay, the second input end of the second differential circuit is connected to the first contact of the relay, the output end of the second differential circuit is connected to the positive pole of the third diode, the cathode of the second diode and the cathode of the third diode are connected to the control end of the trigger circuit, and the output end of the trigger circuit is connected to the input end of the coil control circuit.

[0013] Optionally, the first differential circuit includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a first capacitor, a second capacitor, a third capacitor and a first operational amplifier; the first end of the sixth resistor is connected to the first contact of the relay, the second end of the sixth resistor is connected to the first end of the seventh resistor and the first end of the eighth resistor, the second end of the seventh resistor is connected to the inverting input terminal of the first operational amplifier, the first end of the ninth resistor and the first end of the first capacitor, the second end of the ninth resistor is connected to the second end of the first capacitor, the first end of the tenth resistor and the output terminal of the first operational amplifier, The second end of the tenth resistor is connected to the first end of the third capacitor; the first end of the eleventh resistor is connected to the second contact of the relay, the second end of the eleventh resistor is connected to the first end of the twelfth resistor and the first end of the thirteenth resistor, the second end of the twelfth resistor is connected to the first end of the fourteenth resistor and the non-inverting input terminal of the first operational amplifier, the power pin of the first operational amplifier is connected to the power supply terminal of the first operational amplifier and the first end of the second capacitor, the second end of the eighth resistor, the second end of the thirteenth resistor, the second end of the fourteenth resistor, the second end of the second capacitor, the second end of the third capacitor and the ground pin of the first operational amplifier are connected to the same potential.

[0014] Optionally, the second differential circuit includes a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a fourth capacitor, a fifth capacitor, a sixth capacitor, and a second operational amplifier; the first end of the fifteenth resistor is connected to the second contact of the relay, the second end of the fifteenth resistor is connected to the first end of the sixteenth resistor and the first end of the seventeenth resistor, the second end of the sixteenth resistor is connected to the inverting input terminal of the second operational amplifier, the first end of the eighteenth resistor and the first end of the fourth capacitor, the second end of the eighteenth resistor is connected to the second end of the fourth capacitor, the first end of the nineteenth resistor and the input terminal of the second operational amplifier. an output terminal, the second end of the nineteenth resistor is connected to the first end of the sixth capacitor; the first end of the twentieth resistor is connected to the first contact of the relay, the second end of the twentieth resistor is connected to the first end of the twenty-first resistor and the first end of the twenty-second resistor, the second end of the twenty-first resistor is connected to the first end of the twenty-third resistor and the non-inverting input terminal of the second operational amplifier, the power supply pin of the second operational amplifier is connected to the power supply terminal of the second operational amplifier and the first end of the fifth capacitor, the second end of the seventeenth resistor, the second end of the twenty-second resistor, the second end of the twenty-third resistor, the second end of the fifth capacitor, the second end of the sixth capacitor and the ground pin of the second operational amplifier are connected to the same potential.

[0015] Optionally, the trigger circuit includes a voltage regulator, a photocoupler, a twenty-fourth resistor and a twenty-fifth resistor, the photocoupler includes a light-emitting diode and a photosensor, the reference end of the voltage regulator is connected to the cathode of the second diode and the cathode of the third diode, the positive end of the voltage regulator is connected to the first end of the twenty-fourth resistor and the cathode of the light-emitting diode, the second end of the twenty-fourth resistor is connected to the positive end of the light-emitting diode and the first end of the twenty-fifth resistor, the second end of the twenty-fifth resistor is connected to the first power supply end of the trigger circuit, the first end of the photosensor is connected to the second power supply end of the trigger circuit, the second end of the photosensor is connected to the output end of the voltage difference detection circuit, and the negative end of the voltage regulator is connected to the equipotential potential.

[0016] A second aspect of the embodiments of the present application provides a vehicle, comprising the relay control circuit and the relay described in any one of the first aspect of the embodiments of the present application.

[0017] The relay control circuit of the embodiment of the present application includes a pressure difference detection circuit and a coil control circuit, wherein a first input end of the pressure difference detection circuit is connected to a first contact of the relay, a second input end of the pressure difference detection circuit is connected to a second contact of the relay, an output end of the pressure difference detection circuit is connected to an input end of the coil control circuit, a first control end of the coil control circuit is connected to a first end of the coil of the relay, and a second control end of the coil control circuit is connected to a second end of the coil of the relay. In the embodiment of the present application, when the pressure difference detection circuit detects that the pressure difference between the first contact of the relay and the second contact of the relay is greater than a set value, the output end of the pressure difference detection circuit outputs a high-level signal, which makes it impossible for the coil control circuit to control the coil of the relay to be energized, so that the relay is disconnected. When the voltage across the relay is too large, the relay can be controlled to disconnect through the hardware circuit, thereby reducing the risk of overcurrent adhesion of the relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic structural diagram of a relay control circuit provided in an embodiment of the present application;

[0020] Figure 2 This is a schematic structural diagram of a coil control circuit provided in an embodiment of the present application;

[0021] Figure 3 Schematic diagram of a voltage difference detection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0023] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, product, or apparatus.

[0024] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0025] Relays (e.g., high-voltage DC relays) are key components of the electrical systems of new energy vehicles, with resistance to high voltage, high temperature, shock, and strong circuit-breaking capabilities. A relay is a switching device that can control a larger current with a smaller current and has a protective function. It plays a vital role between the high-voltage battery pack and the various electrical units of an electric vehicle, ensuring that the electrical system can be safely connected and disconnected. It can isolate the circuit when the vehicle stops working and connect the circuit when the vehicle is running. In addition, when the vehicle is turned off or a problem occurs, it can ensure that the energy storage system is safely separated from the vehicle's electrical system, serving as a circuit breaker. New energy vehicles have spurred demand for high-voltage DC relays, and the market is growing rapidly and sustainably.

[0026] At the same time, relays in new energy vehicles often experience problems due to improper control, especially during repeated starts and stops. This can cause excessive voltage across the relay, resulting in high current when the relay closes. This can lead to relay failure due to overcurrent, or even burnout of the entire circuit control unit due to overcurrent, causing significant losses.

[0027] For new energy vehicles, relay overcurrent adhesion failure is a major problem that needs to be solved increasingly urgently. The embodiment of the present application designs a relay control circuit that can prevent the relay from generating high current and causing failure when closed.

[0028] See also Figure 1 , Figure 1 This is a schematic diagram of the structure of a relay control circuit provided by an embodiment of the present application. Figure 1As shown, the relay control circuit 100 includes a pressure difference detection circuit 10 and a coil control circuit 20, wherein a first input terminal of the pressure difference detection circuit 10 is connected to a first contact 4 of the relay K1, a second input terminal of the pressure difference detection circuit 10 is connected to a second contact 3 of the relay K1, an output terminal of the pressure difference detection circuit 10 is connected to an input terminal of the coil control circuit 20, a first control terminal of the coil control circuit 20 is connected to a first terminal 1 of the coil of the relay K1, and a second control terminal of the coil control circuit 20 is connected to a second terminal 2 of the coil of the relay K1;

[0029] When the pressure difference detection circuit 10 detects that the pressure difference between the first contact 4 of the relay K1 and the second contact 3 of the relay K1 is greater than a set value, the output end of the pressure difference detection circuit 10 outputs a high-level signal. The high-level signal causes the coil control circuit 20 to control the coil of the relay K1 to be unable to be excited, so that the relay K1 is disconnected.

[0030] When the pressure difference detection circuit 10 detects that the pressure difference between the first contact 4 of the relay K1 and the second contact 3 of the relay K1 is less than the set value, the output end of the pressure difference detection circuit 10 outputs a low-level signal, and the low-level signal causes the coil control circuit 20 to allow the coil of the relay K1 to be excited, so that the relay K1 is closed.

[0031] The voltage at the first contact 4 of the relay K1 is V1, and the voltage at the second contact 3 of the relay K1 is V2. The voltage difference between the first contact and the second contact 3 of the relay K1 is the absolute value of (V1-V2).

[0032] The pressure difference detection circuit 10 and the coil control circuit 20 are hardware circuits.

[0033] The set value can be a voltage threshold set by the pressure difference detection circuit 10. When the pressure difference between the first contact 4 of the relay K1 and the second contact 3 of the relay K1 is greater than the set value, the pressure difference detection circuit 10 outputs a high-level signal; when the pressure difference between the first contact 4 of the relay K1 and the second contact 3 of the relay K1 is less than the set value, the pressure difference detection circuit 10 outputs a low-level signal.

[0034] The high-level signal may be an analog signal whose voltage is greater than a set threshold. For example, the high-level signal may be a signal with a voltage of 5V, and the set threshold may be set to 1V.

[0035] The low level signal may be a signal whose voltage is less than a set threshold value. For example, the low level signal may be a signal whose voltage is 0V, and the set threshold value may be set to 1V.

[0036] The coil of relay K1 cannot be excited, which means that the coil of relay K1 is not energized. When the coil of relay K1 is not energized, the first contact 4 and the second contact of relay K1 cannot be attracted, thereby disconnecting relay K1.

[0037] The coil excitation of the relay K1 refers to the coil of the relay K1 being energized. When the coil of the relay K1 is energized, the first contact 4 and the second contact 3 of the relay K1 are triggered to be attracted, thereby closing the relay K1.

[0038] Allowing the coil of relay K1 to be excited means that when power is supplied to the coil of relay K1, the coil of relay K1 can be energized.

[0039] In the embodiment of the present application, when the pressure difference detection circuit 10 detects that the pressure difference between the first contact 4 of the relay K1 and the second contact 3 of the relay K1 is greater than a set value, the output terminal of the pressure difference detection circuit 10 outputs a high-level signal. This high-level signal prevents the coil control circuit 20 from controlling the coil of the relay K1 from being excited, thereby disconnecting the relay K1. When the voltage across the relay K1 is too high, the hardware circuit can be used to control the relay K1 to disconnect, thereby reducing the risk of overcurrent adhesion of the relay K1. When the voltage across the relay K1 is low, the hardware circuit can be used to allow the relay K1 to close, and when the voltage across the relay K1 is low, the relay K1 can be allowed to operate normally.

[0040] See also Figure 2 , Figure 2 This is a schematic diagram of the structure of a coil control circuit provided in an embodiment of the present application. Figure 2 As shown, the coil control circuit includes a first control circuit 21 and a second control circuit 22. The first input end of the first control circuit 21 is connected to the output end of the pressure difference detection circuit 10 (such as Figure 2 VS2' is a signal outputted from the output terminal of the voltage difference detection circuit 10), and the second input terminal of the first control circuit 21 is connected to the signal output terminal of the control module (eg Figure 2 VC1 is a signal output from the signal output terminal of the control module), the first control terminal of the first control circuit 21 is connected to the first control terminal of the second control circuit 22 and the first end 1 of the coil of the relay K1, the second control terminal of the second control circuit 22 is connected to the second end 2 of the coil of the relay K1, and the input terminal of the second control circuit 22 is connected to the power supply terminal of the coil of the relay K1 (as shown in FIG. Figure 2 VS1 shown is the supply voltage for energizing the coil of relay K1).

[0041] Figure 2The control module is not shown. The control module may be a device that controls relay K1, for example, a control chip. The control module can control the closing or closing of relay K1 via a signal VC1 output from a signal output terminal of the control module. When the control module controls relay K1 to close, VC1 is a high-level signal; when the control module controls relay K1 to open, VC1 is a low-level signal.

[0042] VS1 is the power supply voltage for the coil of the relay K1. VS1 is a high-level signal. For example, VS1 may be 12V.

[0043] Optional, such as Figure 2 As shown, the first control circuit 21 includes: a first switch tube Q1, a second switch tube Q2, a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, the first end of the first resistor R1 is connected to the output end of the voltage difference detection circuit 10, the second end of the first resistor R1 is connected to the first end of the second resistor R2 and the control end of the first switch tube Q1, the first end of the first switch tube Q1 is connected to the second end of the third resistor R3, the first end of the fourth resistor R4 and the control end of the second switch tube Q2, the first end of the second switch is connected to the first end 1 of the coil of the relay K1, the first end of the third resistor R3 is connected to the signal output end of the control module, the second end of the first switch tube Q1, the second end of the fourth resistor R4 and the second end of the second switch tube Q2 are connected to the equipotential potential (such as Figure 2 triangle shown).

[0044] The equipotential point is a position where the electric potential is equal, and the electric potential of all ports connected to the equipotential point is equal. For example, the equipotential point can be grounded.

[0045] The first switch tube Q1 and the second switch tube Q2 can be any device that can be used as a switch, such as a triode, a field effect transistor, etc. Figure 2 The first switch tube Q1 is an N-type metal-oxide-semiconductor field-effect transistor (MOSFET), referred to as NMOS tube. Figure 2 The second switch tube Q2 is an NPN transistor.

[0046] Optional, such as Figure 2As shown, the second control circuit 22 includes: a first diode D1 and a fifth resistor R5, the positive electrode of the first diode D1 is connected to the first end 1 of the coil of the relay K1, the negative electrode of the first diode D1 is connected to the second end 2 of the coil of the relay K1 and the second end of the fifth resistor R5, and the first end of the fifth resistor R5 is connected to the power supply end of the coil of the relay K1.

[0047] The first diode D1 is a freewheeling diode. When relay K1 switches from a closed state to an open state, a self-induced electromotive force (EMF) is generated in the coil of relay K1. If this self-induced EMF directly acts on other components in the circuit (for example, sensitive components such as transistors and microcontrollers), it may cause damage. By connecting the first diode D1 in parallel across the coil of relay K1, a discharge current loop is provided for the self-induced EMF when relay K1 is opened. In other words, the first diode D1 acts as a freewheeling diode.

[0048] Optional, such as Figure 2 As shown, a fourth diode D4 and a twenty-sixth resistor R26 can be connected in parallel between the first contact 4 and the second contact 3 of relay K1. Fourth diode D4 is a freewheeling diode. When relay K1 switches from a closed state to an open state, a high reverse voltage is generated between the first contact 4 and the second contact 3 of relay K1. The generated reverse voltage can be dissipated through fourth diode D4 and twenty-sixth resistor R26. Twenty-sixth resistor R26 is a current-limiting resistor that can limit the current flowing through fourth diode D4 during the reverse voltage release process to avoid damage to the device.

[0049] like Figure 2 As shown, when the voltage difference across relay K1 is large, the signal VS2' outputted by the output terminal of the voltage difference detection circuit 10 is a high-level signal. The voltage divider circuit formed by the first resistor R1 and the second resistor R2 causes the gate of the first switch tube Q1 to be a high-level signal, turning on the first switch tube Q1. After the first switch tube Q1 is turned on, the voltage of the collector of the second switch tube Q2 is lowered, causing the second switch tube Q2 to be unable to turn on, and the relay K1 coil cannot be energized, causing the relay K1 to disconnect. When the voltage difference across relay K1 is large, the hardware circuit can be used to control the relay K1 to disconnect, thereby reducing the risk of overcurrent adhesion of relay K1.

[0050] like Figure 2As shown, when the voltage difference across relay K1 is small, the signal VS2' outputted from the output terminal of the voltage difference detection circuit 10 is a low-level signal. The voltage divider circuit formed by the first resistor R1 and the second resistor R2 causes the gate of the first switch Q1 to be low, causing the first switch Q1 to be off. When the control module needs to control relay K1 to be closed, VC1 becomes a high-level signal. The voltage divider circuit formed by the third resistor R3 and the fourth resistor R4 causes the base of the second switch Q2 to be high-level, causing the second switch Q2 to be conductive, energizing the coil of relay K1 and closing relay K1. When the voltage difference across relay K1 is small, relay K1 can be closed by controlling the hardware circuit, thereby enabling relay K1 to operate normally.

[0051] See also Figure 3 , Figure 3 Schematic diagram of a voltage difference detection circuit provided in an embodiment of the present application. Figure 3 As shown, the pressure difference detection circuit includes: a first differential circuit 11, a second differential circuit 12, a second diode D2, a third diode D3 and a trigger circuit 13, wherein the first input end of the first differential circuit 11 is connected to the first contact 4 of the relay K1, the second input end of the first differential circuit 11 is connected to the second contact 3 of the relay K1, the output end of the first differential circuit 11 is connected to the anode of the second diode D2, the first input end of the second differential circuit 12 is connected to the second contact 3 of the relay K1, the second input end of the second differential circuit 12 is connected to the first contact 4 of the relay K1, the output end of the second differential circuit 12 is connected to the anode of the third diode D3, the cathode of the second diode D2 and the cathode of the third diode D3 are connected to the control end of the trigger circuit 13, and the output end of the trigger circuit 13 is connected to the input end of the coil control circuit 20.

[0052] When the voltage difference between the first contact 4 of relay K1 and the second contact 3 of relay K1 exceeds a set value, the output of the first differential circuit 11 or the output of the second voltage differential circuit outputs a high-level signal. If the voltage at the first contact 4 of relay K1 is V1 and the voltage at the second contact 3 of relay K1 is V2, then if V1 - V2 > the set value, the output of the second voltage differential circuit outputs a high-level signal, turning on the third diode D3 and causing the output of the trigger circuit 13 to output a high-level signal. If V2 - V1 > the set value, the output of the first differential circuit 11 outputs a high-level signal, turning on the second diode D2 and causing the output of the trigger circuit 13 to output a high-level signal.

[0053] When the voltage difference between the first contact 4 of relay K1 and the second contact 3 of relay K1 is less than a set value, the output of the first differential circuit 11 or the output of the second voltage differential circuit outputs a low-level signal. If the voltage at the first contact 4 of relay K1 is V1 and the voltage at the second contact 3 of relay K1 is V2, then if V1-V2 < the set value and V2-V1 < the set value, both the output of the first differential circuit 11 and the output of the second voltage differential circuit output a low-level signal, turning off the second diode D2 and the third diode D3, causing the output of the trigger circuit 13 to output a low-level signal.

[0054] Optional, such as Figure 3 As shown, the first differential circuit 11 includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a first capacitor C1, a second capacitor C2, a third capacitor C3 and a first operational amplifier U1; a first end of the sixth resistor R6 is connected to the first contact 4 of the relay K1, a second end of the sixth resistor R6 is connected to the first end of the seventh resistor R7 and the first end of the eighth resistor R8, a second end of the seventh resistor R7 is connected to the inverting input terminal of the first operational amplifier U1, the first end of the ninth resistor R9 and the first end of the first capacitor C1, and a second end of the ninth resistor R9 is connected to the second end of the first capacitor C1, the first end of the tenth resistor R10 and the first operational amplifier U1. 1, the second end of the tenth resistor R10 is connected to the first end of the third capacitor C3; the first end of the eleventh resistor R11 is connected to the second contact 3 of the relay K1, the second end of the eleventh resistor R11 is connected to the first end of the twelfth resistor R12 and the first end of the thirteenth resistor R13, the second end of the twelfth resistor R12 is connected to the first end of the fourteenth resistor R14 and the non-inverting input end of the first operational amplifier U1, the power supply pin of the first operational amplifier U1 is connected to the power supply end of the first operational amplifier U1 and the first end of the second capacitor C2, the second end of the eighth resistor R8, the second end of the thirteenth resistor R13, the second end of the fourteenth resistor R14, the second end of the second capacitor C2, the second end of the third capacitor C3 and the ground pin of the first operational amplifier U1 are connected to the same potential.

[0055] Optional, such as Figure 3As shown, the second differential circuit 12 includes a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6 and a second operational amplifier U2; a first end of the fifteenth resistor R15 is connected to the second contact 3 of the relay K1, a second end of the fifteenth resistor R15 is connected to the first end of the sixteenth resistor R16 and the first end of the seventeenth resistor R17, a second end of the sixteenth resistor R16 is connected to the inverting input terminal of the second operational amplifier U2, the first end of the eighteenth resistor R18 and the first end of the fourth capacitor C4, a second end of the eighteenth resistor R18 is connected to the second end of the fourth capacitor C4, the first end of the nineteenth resistor R19 and the The output end of the second operational amplifier U2, the second end of the nineteenth resistor R19 is connected to the first end of the sixth capacitor C6; the first end of the twentieth resistor R20 is connected to the first contact 4 of the relay K1, the second end of the twentieth resistor R20 is connected to the first end of the twenty-first resistor R21 and the first end of the twenty-second resistor R22, the second end of the twenty-first resistor R21 is connected to the first end of the twenty-third resistor R23 and the non-inverting input end of the second operational amplifier U2, the power supply pin of the second operational amplifier U2 is connected to the power supply end of the second operational amplifier U2 and the first end of the fifth capacitor C5, the second end of the seventeenth resistor R17, the second end of the twenty-second resistor R22, the second end of the twenty-third resistor R23, the second end of the fifth capacitor C5, the second end of the sixth capacitor C6 and the ground pin of the second operational amplifier U2 are connected to the same potential.

[0056] Optional, such as Figure 3 As shown, the trigger circuit 13 includes a voltage regulator U3, a photocoupler U4, a twenty-fourth resistor R24 ​​and a twenty-fifth resistor R25, the photocoupler U4 includes a light-emitting diode and a photosensor, the reference end of the voltage regulator U3 is connected to the cathode of the second diode D2 and the cathode of the third diode D3, the positive electrode of the voltage regulator U3 is connected to the first end of the twenty-fourth resistor R24 ​​and the cathode of the light-emitting diode, the second end of the twenty-fourth resistor R24 ​​is connected to the positive electrode of the light-emitting diode and the first end of the twenty-fifth resistor R25, the second end of the twenty-fifth resistor R25 is connected to the first power supply end of the trigger circuit 13, the first end of the photosensor is connected to the second power supply end of the trigger circuit 13, the second end of the photosensor is connected to the output end of the voltage difference detection circuit 10, and the negative electrode of the voltage regulator U3 is connected to the equipotential potential.

[0057] The signal at the power supply terminal of the first operational amplifier U1, the signal at the power supply terminal of the second operational amplifier U2, and the signal at the first power supply terminal of the trigger circuit 13 are all VS3. The signal at the second power supply terminal of the trigger circuit 13 is VS2. For example, VS3 can be 5V, and VS2 can be 3V. Both VS2 and VS3 are high-level signals.

[0058] The photosensitive device can be a photodiode, a phototransistor, etc. Figure 3 The photosensitive device is taken as an example of a phototransistor.

[0059] The working principle of the voltage stabilizer U3 is: when the reference end of the voltage stabilizer U3 is a high-level signal, the positive and negative poles of the voltage stabilizer U3 are connected; when the reference end of the voltage stabilizer U3 is a low-level signal, the positive and negative poles of the voltage stabilizer U3 are disconnected.

[0060] The principle of the photocoupler U4 is: when the light-emitting diode is turned on and emits light, the photosensitive device is turned on; when the light-emitting diode is not turned on, it does not emit light and the photosensitive device cannot be turned on.

[0061] Figure 2 is the coil control circuit 20, Figure 3 It is a pressure difference detection circuit 10. The pressure difference detection circuit 10 detects the voltage across the relay K1 (the voltage between the first contact 4 of the relay K1 and the second contact 3 of the relay K1). The pressure difference detection circuit 10 outputs a high-level signal or a low-level signal to the coil control circuit 20 according to the voltage across the relay K1. The coil control circuit 20 controls the relay K1 to open according to the high-level signal and controls the relay K1 to close according to the low-level signal. The relay K1 can be accurately closed to avoid damage to the relay K1 due to the large current generated when the relay K1 is closed.

[0062] The following combination Figure 2 and Figure 3 The circuit explains the working principle:

[0063] When the voltage difference between the two ends of relay K1 is relatively large, that is, V1-V2>30V (the set value can be set to 30V), or V2-V1>30V. Figure 3 As shown, the voltage difference between V1 and V2 passes through the first differential circuit 11 and the second differential circuit 12, and the output end of the first operational amplifier U1 outputs a high-level signal or the output end of the second operational amplifier U2 outputs a high-level signal. After passing through the second diode D2 or the third diode D3, the positive and negative electrodes of the voltage regulator U3 are connected, so that the light-emitting diode of the photocoupler U4 is turned on and emits light, thereby turning on the photosensitive device of the photocoupler U4. VS2 is transmitted through the first end of the photosensitive device to the second end of the photosensitive device, making VS2' a high-level signal. Figure 2As shown, VS2' is a high-level signal, which turns on the first switch Q1 and causes the second switch Q2 to be unable to turn on. The coil of relay K1 cannot be excited and relay K1 cannot be closed. Due to the large voltage difference between the two ends of relay K1, the instantaneous current of relay K1 closing will reach hundreds of amperes. The greater the voltage difference, the greater the current, which will cause the internal contacts of relay K1 to stick and fail. At this time, Figure 2 and Figure 3 The circuit disconnects relay K1, thereby avoiding the internal contact failure of relay K1.

[0064] When the voltage difference between the two ends of relay K1 is small, that is, V1-V2<30V (the set value can be set to 30V), or V2-V1<30V. Figure 3 As shown, the voltage difference between V1 and V2 passes through the first differential circuit 11 and the second differential circuit 12. The output end of the first operational amplifier U1 outputs a low-level signal and the output end of the second operational amplifier U2 outputs a low-level signal. The low-level signal cannot turn on the second diode D2 and the third diode D3, making the positive and negative electrodes of the voltage regulator U3 unable to conduct, making the light-emitting diode of the photocoupler U4 unable to conduct and emit light, and further making the photosensor of the photocoupler U4 unable to conduct, and VS2' is a low-level signal. Figure 2 As shown, VS2' is a low-level signal, which turns off the first switch Q1 and turns on the second switch Q2. This energizes the coil of relay K1, closing it. Since the voltage difference across relay K1 is relatively small, closing relay K1 does not generate a large current, allowing relay K1 to close.

[0065] In the embodiment of the present application, by accurately controlling the closing and opening of the relay K1, a large current generated by closing the relay K1 is avoided, thereby improving the safety of the vehicle and the application in complex scenarios.

[0066] The embodiment of the present application further provides a vehicle, which may include Figure 1 The relay K1 controls the circuit 100 and the relay K1.

[0067] The specific structure of the relay K1 control circuit 100 can be found in the above Figures 1 to 3 circuit.

[0068] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0069] In the several embodiments provided herein, it should be understood that the disclosed relay K1 control circuit can be implemented in other ways. For example, the relay K1 control circuit embodiment described above is merely illustrative. For example, the division of the units described is merely a logical functional division. In actual implementation, other division methods may be used. For example, multiple units or components may be combined or integrated into another system, or some features may be omitted or not implemented.

Claims

1. A relay control circuit, characterized in that: The device comprises a pressure difference detection circuit and a coil control circuit, wherein a first input end of the pressure difference detection circuit is connected to a first contact of a relay, a second input end of the pressure difference detection circuit is connected to a second contact of the relay, an output end of the pressure difference detection circuit is connected to an input end of the coil control circuit, a first control end of the coil control circuit is connected to a first end of the coil of the relay, and a second control end of the coil control circuit is connected to a second end of the coil of the relay; When the pressure difference detection circuit detects that the pressure difference between the first contact of the relay and the second contact of the relay is greater than a set value, the output end of the pressure difference detection circuit outputs a high-level signal, and the high-level signal causes the coil control circuit to control the coil of the relay to be unable to be energized, so that the relay is disconnected.

2. The relay control circuit according to claim 1, characterized in that: When the pressure difference detection circuit detects that the pressure difference between the first contact of the relay and the second contact of the relay is less than the set value, the output end of the pressure difference detection circuit outputs a low-level signal, and the low-level signal causes the coil control circuit to allow the coil of the relay to be excited to close the relay.

3. The relay control circuit according to claim 1, characterized in that: The coil control circuit includes a first control circuit and a second control circuit, the first input end of the first control circuit is connected to the output end of the pressure difference detection circuit, the second input end of the first control circuit is connected to the signal output end of the control module, the first control end of the first control circuit is connected to the first control end of the second control circuit and the first end of the coil of the relay, the second control end of the second control circuit is connected to the second end of the coil of the relay, and the input end of the second control circuit is connected to the power supply end of the coil of the relay.

4. The relay control circuit according to claim 3, characterized in that: The first control circuit includes: a first switching tube, a second switching tube, a first resistor, a second resistor, a third resistor and a fourth resistor, wherein the first end of the first resistor is connected to the output end of the voltage difference detection circuit, the second end of the first resistor is connected to the first end of the second resistor and the control end of the first switching tube, the first end of the first switching tube is connected to the second end of the third resistor, the first end of the fourth resistor and the control end of the second switching tube, the first end of the second switch is connected to the first end of the coil of the relay, the first end of the third resistor is connected to the signal output end of the control module, and the second end of the first switching tube, the second end of the fourth resistor and the second end of the second switching tube are connected to the same potential.

5. The relay control circuit according to claim 3, characterized in that: The second control circuit includes: a first diode and a fifth resistor, the positive electrode of the first diode is connected to the first end of the coil of the relay, the negative electrode of the first diode is connected to the second end of the coil of the relay and the second end of the fifth resistor, and the first end of the fifth resistor is connected to the power supply end of the coil of the relay.

6. The relay control circuit according to any one of claims 1 to 5, characterized in that: The pressure difference detection circuit includes: a first differential circuit, a second differential circuit, a second diode, a third diode and a trigger circuit, wherein the first input end of the first differential circuit is connected to the first contact of the relay, the second input end of the first differential circuit is connected to the second contact of the relay, the output end of the first differential circuit is connected to the anode of the second diode, the first input end of the second differential circuit is connected to the second contact of the relay, the second input end of the second differential circuit is connected to the first contact of the relay, the output end of the second differential circuit is connected to the anode of the third diode, the cathode of the second diode and the cathode of the third diode are connected to the control end of the trigger circuit, and the output end of the trigger circuit is connected to the input end of the coil control circuit.

7. The relay control circuit according to claim 6, characterized in that: The first differential circuit includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a first capacitor, a second capacitor, a third capacitor and a first operational amplifier; a first end of the sixth resistor is connected to the first contact of the relay, a second end of the sixth resistor is connected to the first end of the seventh resistor and the first end of the eighth resistor, a second end of the seventh resistor is connected to the inverting input terminal of the first operational amplifier, the first end of the ninth resistor and the first end of the first capacitor, a second end of the ninth resistor is connected to the second end of the first capacitor, the first end of the tenth resistor and the output terminal of the first operational amplifier, and the first end of the ninth resistor is connected to the second end of the first capacitor. The second end of the tenth resistor is connected to the first end of the third capacitor; the first end of the eleventh resistor is connected to the second contact of the relay, the second end of the eleventh resistor is connected to the first end of the twelfth resistor and the first end of the thirteenth resistor, the second end of the twelfth resistor is connected to the first end of the fourteenth resistor and the non-inverting input terminal of the first operational amplifier, the power pin of the first operational amplifier is connected to the power supply terminal of the first operational amplifier and the first end of the second capacitor, the second end of the eighth resistor, the second end of the thirteenth resistor, the second end of the fourteenth resistor, the second end of the second capacitor, the second end of the third capacitor and the ground pin of the first operational amplifier are connected to the same potential.

8. The relay control circuit according to claim 6, characterized in that: The second differential circuit includes a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a fourth capacitor, a fifth capacitor, a sixth capacitor, and a second operational amplifier; a first end of the fifteenth resistor is connected to the second contact of the relay, a second end of the fifteenth resistor is connected to the first end of the sixteenth resistor and the first end of the seventeenth resistor, a second end of the sixteenth resistor is connected to the inverting input terminal of the second operational amplifier, the first end of the eighteenth resistor, and the first end of the fourth capacitor, and a second end of the eighteenth resistor is connected to the second end of the fourth capacitor, the first end of the nineteenth resistor, and the output terminal of the second operational amplifier. , the second end of the nineteenth resistor is connected to the first end of the sixth capacitor; the first end of the twentieth resistor is connected to the first contact of the relay, the second end of the twentieth resistor is connected to the first end of the twenty-first resistor and the first end of the twenty-second resistor, the second end of the twenty-first resistor is connected to the first end of the twenty-third resistor and the non-inverting input terminal of the second operational amplifier, the power pin of the second operational amplifier is connected to the power supply terminal of the second operational amplifier and the first end of the fifth capacitor, the second end of the seventeenth resistor, the second end of the twenty-second resistor, the second end of the twenty-third resistor, the second end of the fifth capacitor, the second end of the sixth capacitor and the ground pin of the second operational amplifier are connected to the same potential.

9. The relay control circuit according to claim 6, characterized in that: The trigger circuit includes a voltage regulator, a photoelectric coupler, a twenty-fourth resistor and a twenty-fifth resistor. The photoelectric coupler includes a light-emitting diode and a photosensor. The reference end of the voltage regulator is connected to the cathode of the second diode and the cathode of the third diode. The positive end of the voltage regulator is connected to the first end of the twenty-fourth resistor and the cathode of the light-emitting diode. The second end of the twenty-fourth resistor is connected to the positive end of the light-emitting diode and the first end of the twenty-fifth resistor. The second end of the twenty-fifth resistor is connected to the first power supply end of the trigger circuit. The first end of the photosensor is connected to the second power supply end of the trigger circuit. The second end of the photosensor is connected to the output end of the voltage difference detection circuit. The negative end of the voltage regulator is connected to the equipotential potential.

10. A vehicle, characterized in that: The invention comprises the relay control circuit and the relay according to any one of claims 1 to 9.

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