Motor open circuit protection circuit, motor driving system and vehicle

Abstract

The invention provides a motor open circuit protection circuit, a motor driving system and a vehicle, and the motor open circuit protection circuit comprises a first switch module and a control module. Wherein the first end of the first switch module is used for connecting a power battery, and the second end of the first switch module is used for connecting a power module. The control module is electrically connected with the control end of the first switch module, and the control module is configured to control the first switch module to disconnect the electric connection between the power battery and the power module when detecting that the first end voltage of the first switch module is smaller than the second end voltage of the first switch module and the duration time meets the preset duration. It can be understood that when it is detected that the first terminal voltage of the first switch module is lower than the second terminal voltage of the first switch module and the preset time is delayed, the rotating speed of the motor is reduced, and at the moment, the control module controls the first switch module to be disconnected, so that high electromotive force is prevented from being accumulated at the power module, the breakdown risk of the circuit is reduced, and the safety of the circuit is improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a motor open circuit protection circuit, a motor drive system and a vehicle. Background Art

[0002] The electric drive system is a core component of new energy vehicles, converting electrical energy into mechanical energy to propel the vehicle forward. When a fault occurs in the electric drive system of a new energy vehicle, the controller typically directs the system into a safe operating state, thereby mitigating vehicle safety risks.

[0003] In related technologies, when a fault occurs in the electric drive system of a new energy vehicle, the controller actively disconnects all the IGBT tubes in the power module (such as the inverter) (i.e., the open circuit protection working state), thereby disconnecting the high-voltage AC power supply to the motor, thereby isolating the motor from the power battery and the controller.

[0004] However, when the motor speed is high and the open-circuit protection is in operation, the back electromotive force generated by the motor is also relatively high. Directly disconnecting the electrical connection between the power supply and the motor may cause a high electromotive force to accumulate at the power module, posing a greater risk of circuit breakdown.

[0005] It should be pointed out that the information disclosed in the background technology section of this application is only intended to deepen the understanding of the general background technology of this application, and should not be regarded as an admission or any form of implication that the information constitutes prior art already known to those skilled in the art. Summary of the Invention

[0006] In view of this, the present application provides a motor open circuit protection circuit, a motor drive system and a vehicle. The motor open circuit protection circuit is used to solve the problem in the prior art that in the open circuit protection working state, when the motor speed is high, the back electromotive force generated by the motor is also relatively high, which makes the circuit breakdown risk greater.

[0007] In a first aspect, an embodiment of the present application provides a motor open circuit protection circuit, comprising:

[0008] a first switch module, wherein a first end of the first switch module is used to connect to a power battery, and a second end of the first switch module is used to connect to a power module;

[0009] A control module, connected to the control end of the first switch module, and configured to:

[0010] When it is detected that the voltage at the first terminal of the first switch module is less than the voltage at the second terminal thereof and the duration meets a preset time length, the first switch module is controlled to disconnect the electrical connection between the power battery and the power module.

[0011] In a possible implementation, the control module includes a comparison unit, a delay unit, and a control unit connected in sequence; wherein,

[0012] The first input end of the comparison unit is connected to the first end of the first switch module, and the second input end of the comparison unit is connected to the second end of the first switch module;

[0013] The comparison unit is configured to:

[0014] When the voltage at the first end of the first switch module is less than the voltage at the second end of the first switch module, output a first signal;

[0015] The delay unit is configured as follows:

[0016] When the first signal is received and the first signal lasts for the preset time period, outputting a second signal;

[0017] The control unit is configured to:

[0018] After receiving the second signal, the first switch module is controlled to disconnect the power battery and the power module.

[0019] In a possible implementation, the first switch module includes a relay, a control coil of the relay is connected to the control unit, a first end of the relay is connected to the power battery, and a second end of the relay is connected to the power module.

[0020] In one possible implementation, the comparison unit includes a comparator, the non-inverting input of the comparator is connected to the first end of the first switch module, the inverting input of the comparator is connected to the second end of the first switch module, and the output of the comparator is connected to the delay unit.

[0021] In a possible implementation, the delay unit includes a switch tube, a capacitor, a first resistor, and a second resistor; a control terminal of the switch tube is connected to the output terminal of the comparison unit, and an input terminal of the switch tube is connected to a preset power supply;

[0022] The first end of the capacitor, the first end of the first resistor and the first end of the second resistor are all connected to the output end of the switching tube, the second end of the capacitor and the second end of the first resistor are grounded, and the second end of the second resistor is connected to the control unit.

[0023] In a possible implementation, the control unit includes a switch tube, the input and output ends of the switch tube and the control coil of the relay are sequentially connected in series between a preset power supply and ground, and the control end of the switch tube is connected to the delay unit.

[0024] In a possible implementation, the motor open circuit protection circuit further includes a second switch module, wherein a first end of the second switch module is used to connect to a power battery, and a second end of the second switch module is used to connect to a power module;

[0025] The second switch module is configured as follows:

[0026] When the voltage at the first terminal of the second switch module is greater than or equal to the voltage at the second terminal of the second switch module, conducting the electrical connection between the power battery and the power module;

[0027] When the voltage at the first terminal of the second switch module is lower than the voltage at the second terminal of the second switch module, the electrical connection between the power battery and the power module is disconnected.

[0028] In a possible implementation, the second switch module includes a thyristor.

[0029] In a second aspect, an embodiment of the present application provides a motor drive system, including a power battery and a power module, and further including: a motor open circuit protection circuit as described in any one of the first aspects;

[0030] The motor open circuit protection circuit is connected between the power battery and the power module.

[0031] In a third aspect, an embodiment of the present application provides a vehicle comprising the motor drive system as described in the second aspect.

[0032] In an embodiment of the present application, the motor open-circuit protection circuit includes a first switch module and a control module. The first terminal of the first switch module is connected to a power battery, and the second terminal of the first switch module is connected to a power module. The control module is electrically connected to the control terminal of the first switch module. The control module is configured to control the first switch module to disconnect the electrical connection between the power battery and the power module when it detects that the voltage at the first terminal of the first switch module is less than the voltage at the second terminal of the first switch module for a predetermined duration.

[0033] It is understood that when the voltage at the first terminal of the first switching module is less than the voltage at its second terminal and the duration does not meet the preset duration, current will be generated in the circuit due to the conduction between the power battery and the power module. In this case, the current flows from the power module to the power battery. The rotating motor at this time acts as a generator. At the same time, the motor's rotor coil is subjected to the Ampere force, which hinders the motor's rotation. Therefore, within the preset duration, the motor can achieve a reduced speed, achieving the effect of braking and deceleration. At the same time, the vehicle will not lose control due to rapid braking, thereby improving user driving safety.

[0034] When the first switch module disconnects the electrical connection between the power battery and the power module, the motor speed is low at this time, so it can also avoid the accumulation of high electromotive force at the power module, reducing the risk of circuit breakdown and improving the safety of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 A schematic diagram of an application scenario of a motor drive system provided in an embodiment of the present application.

[0037] Figure 2 A simple circuit diagram of an inverter power supply provided for related technologies.

[0038] Figure 3 A schematic diagram of the structure of a motor drive system provided in an embodiment of the present application.

[0039] Figure 4 A schematic structural diagram of a motor open-circuit protection circuit provided in an embodiment of the present application.

[0040] Figure 5 A schematic diagram of the structure of the control module provided in an embodiment of the present application.

[0041] Figure 6 A schematic diagram of the circuit structure of a comparison unit provided in an embodiment of the present application.

[0042] Figure 7 A schematic diagram of the circuit structure of another comparison unit provided in an embodiment of the present application.

[0043] Figure 8 A schematic diagram of the circuit structure of a delay unit provided in an embodiment of the present application.

[0044] Figure 9 A schematic diagram of the circuit structure of a first switch module provided in an embodiment of the present application.

[0045] Figure 10 A schematic structural diagram of another motor open-circuit protection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0047] It should be clear that 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 ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0048] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0049] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects.

[0050] To facilitate understanding, the following briefly explains the concept of a "power module" as used in the embodiments of this application. The power module referred to in the embodiments of this application refers to a device capable of converting DC power to AC power, such as an inverter, and this application does not impose specific limitations on this. For clarity, the following description uses an inverter as the power module.

[0051] The electric drive system is a core component of new energy vehicles, converting electrical energy into mechanical energy to propel the vehicle forward. To facilitate understanding, the following will first illustrate specific application scenarios.

[0052] See also Figure 1 , is a schematic diagram of an application scenario of a motor drive system provided in an embodiment of the present application. Figure 1 As shown, the motor drive system 100 specifically includes a power battery 101, an inverter module 102, and a motor 103. Specifically, when the motor needs to operate, the power battery provides direct current (DC) to the inverter; the inverter then converts the DC power into alternating current (AC) and supplies power to the motor 103. It should be noted that the inverter 102 is typically used to convert DC power into three-phase AC power.

[0053] For easier understanding, see Figure 2 This is a simplified circuit diagram of an inverter power supply according to related art. As shown, the figure shows an inverter module 102 and a motor 103. Specifically, the inverter module includes six IGBTs (Q1-Q6). It can be understood that by controlling the on / off switching of these six IGBTs, DC power can be converted into three-phase AC power, thereby driving the motor.

[0054] In actual applications, when the electric drive system of a new energy vehicle fails, the controller usually controls the electric drive system of the new energy vehicle to enter a safe working state, thereby reducing the safety risk of the vehicle.

[0055] In related technologies, safe working states mainly include: active short-circuit working state, zero torque control state, and open-circuit working state.

[0056] Specifically, the open-circuit operating state disconnects all six IGBTs in the upper and lower arms of the inverter, effectively disconnecting the high-voltage AC supply to the motor and isolating the motor from the controller. However, this isolation is not complete because the reverse diodes on the IGBTs provide freewheeling.

[0057] Specifically, in the open circuit protection working state, when the motor speed is high, the back electromotive force generated by the motor is also relatively high. Directly disconnecting the electrical connection between the power supply and the motor may cause a high electromotive force to accumulate at the power module, posing a greater risk of circuit breakdown.

[0058] In order to solve the above problems, in the embodiment of the present application, a motor open circuit protection circuit is designed. Under normal conditions, the power battery can supply power to the inverter through the motor open circuit protection circuit. Figure 3 , is a structural diagram of a motor drive system provided in an embodiment of the present application. As shown in the figure, Figure 3 exist Figure 1 The motor open circuit protection circuit 301 is also shown on the basis of FIG. It can be understood that the power battery provides a DC voltage to the inverter through the motor open circuit protection circuit.

[0059] Specifically, in an embodiment of the present application, the motor open-circuit protection circuit includes a first switch module and a control module. The first terminal of the first switch module is connected to a power battery, and the second terminal of the first switch module is connected to a power module. The control module is electrically connected to the control terminal of the first switch module. When it is detected that the voltage at the first terminal of the first switch module is less than the voltage at the second terminal of the first switch module, and the duration of the voltage exceeds a preset time, the control module controls the first switch module to disconnect the electrical connection between the power battery and the power module.

[0060] It is understood that when the voltage at the first terminal of the first switching module is less than the voltage at its second terminal and the duration does not meet the preset duration, current will be generated in the circuit due to the conduction between the power battery and the power module. In this case, the current flows from the power module to the power battery. The rotating motor at this time acts as a generator. At the same time, the motor's rotor coil is subjected to the Ampere force, which hinders the motor's rotation. Therefore, within the preset duration, the motor can achieve a reduced speed, achieving the effect of braking and deceleration. At the same time, the vehicle will not lose control due to rapid braking, thereby improving user driving safety.

[0061] When the first switch module disconnects the electrical connection between the power battery and the power module, the motor speed is low at this time, so it can also avoid the accumulation of high electromotive force at the power module, reducing the risk of circuit breakdown and improving the safety of the circuit.

[0062] See also Figure 4 , is a schematic diagram of the structure of a motor open circuit protection circuit provided by an embodiment of the present application. As shown in the figure, Figure 3 Based on the above, the motor open circuit protection circuit may specifically include a first switch module 401 and a control module 402. The first terminal of the first switch module is used to connect to the power battery, and the second terminal of the first switch module is used to connect to the power module. The control module is electrically connected to the control terminal of the first switch module. The control module is configured to control the first switch module to disconnect the electrical connection between the power battery and the power module when it detects that the voltage at the first terminal of the first switch module is less than the voltage at the second terminal of the first switch module and the duration of the disconnection meets a preset time limit.

[0063] For ease of understanding, this article will introduce relevant details of the first switch module and the control module separately.

[0064] First, the control module.

[0065] In a possible implementation, the control module described above specifically includes a comparison unit, a delay unit, and a control unit connected in sequence. Figure 5 , is a schematic diagram of the structure of the control module provided in an embodiment of the present application. As shown in the figure, the control module 402 is shown. The control module 402 specifically includes: a comparison unit 501, a delay unit 502 and a control unit 503.

[0066] The specific electrical connection relationship is: the first input end of the comparison unit is connected to the first end of the first switch module, the second input end of the comparison unit is connected to the second end of the first switch module; the output end of the control unit is electrically connected to the control end of the first switch module.

[0067] The specific circuit function is: when the voltage at the first end of the first switch module is less than the voltage at the second end of the first switch module, the comparison unit outputs a first signal; when the first signal is received and the first signal lasts for a preset time, the delay unit outputs a second signal; after receiving the second signal, the control unit controls the first switch module to disconnect the connection between the power battery and the power module.

[0068] In the embodiment of the present application, a delay unit in the control module delays the disconnection of the electrical connection between the power battery and the power module, allowing the motor to brake and decelerate using the reverse Ampere force generated by the current. It will be understood that during the delay period of the delay unit, the back electromotive force is higher than the power battery voltage. This back electromotive force will reversely charge the power battery through the first switch module, generating an Ampere force within the motor that hinders its rotation, providing reverse braking torque for the motor. This reduces the motor speed, effectively decelerating the vehicle and improving driving safety.

[0069] After a delay, the motor open-circuit protection circuit disconnects the power battery from the power module. This prevents the circuit from flowing, meaning no current is generated. The motor is forced to slow down due to friction and wind resistance. By properly adjusting the relay's disconnection delay, the motor is applied with varying degrees of braking torque, reducing speed and achieving a braking deceleration effect. This prevents the vehicle from losing control due to rapid braking, improving driving safety.

[0070] At the same time, when the electrical connection between the power battery and the power module is disconnected, due to the low motor speed, the accumulation of high electromotive force at the power module is effectively avoided, the risk of circuit breakdown is reduced, and the safety of the circuit is improved.

[0071] In a possible implementation, the comparison unit specifically includes a comparator. For ease of understanding, see Figure 6 , which is a schematic diagram of the circuit structure of a comparison unit provided in an embodiment of the present application. The non-inverting input terminal of comparator A is electrically connected to the first terminal of the first switch module; the inverting input terminal of comparator A is electrically connected to the second terminal of the first switch module; and the output terminal of comparator A is connected to the delay unit.

[0072] Specifically, the comparator A is configured to output a first signal at an output terminal of the comparator A when the voltage at the first terminal of the first switch module is less than the voltage at the second terminal of the first switch module. Specifically in this embodiment, when the voltage at the first terminal of the first switch module is less than the voltage at the second terminal of the first switch module, the output terminal of the comparator outputs a low-level signal.

[0073] In one possible implementation, in order to ensure that the voltages at the non-inverting input and the inverting input of the comparator in the comparison unit meet the parameter requirements of the comparator, a voltage divider circuit can be set by resistors, and this application does not impose any specific restrictions on this.

[0074] In practical applications, the first signal directly output by the comparator may have a low power problem, which may cause the subsequent delay unit to be unable to accurately identify the first signal. To address this problem, in one possible implementation, a first signal stabilization circuit can be connected to the output of the comparator. Specifically, the first signal stabilization circuit includes a preset power supply, a third resistor, and a fourth resistor.

[0075] For easier understanding, see Figure 7 , is a schematic diagram of the circuit structure of another comparison unit provided in an embodiment of the present application. As shown in the figure, Figure 6 Based on the above, the comparison unit further includes a third resistor R3 and a fourth resistor R4. A preset power supply is electrically connected to a first end of the third resistor; a second end of the third resistor is electrically connected to a first end of the fourth resistor; a second end of the fourth resistor is grounded; and an output terminal of the comparator is electrically connected to a node between the third resistor and the fourth resistor. The node between the third resistor and the fourth resistor serves as the output terminal of the comparison unit.

[0076] It should be pointed out that for the sake of clarity, the default power supply is Figure 7 A 12V power supply is shown in the figure.

[0077] It is understandable that when the output terminal of the comparator outputs a low-level signal, the node between the third resistor and the fourth resistor will be pulled down to a low-level signal, that is, the first signal. Of course, when the output terminal of the comparator outputs a high-level signal, the node between the third resistor and the fourth resistor is usually the power supply after the preset power supply is divided by the third resistor and the fourth resistor. Of course, constructing a comparison unit based on a comparator is only an exemplary description. Relevant technicians in this field can set other circuit structures to realize the function of the comparison unit according to actual needs, and this application does not impose specific limitations on this.

[0078] In one possible implementation, the delay unit described above specifically includes a switch tube, a capacitor, a first resistor, and a second resistor. The switch tube is an electronic device with a switch control function. In one possible implementation, the switch tube may be a MOS tube.

[0079] Of course, using the MOS tube as the switch tube is only an exemplary description. Relevant technicians in this field can choose other electronic devices or design other circuit structures to realize the function of the switch tube according to actual needs. This application does not impose specific restrictions on this.

[0080] For easier understanding, see Figure 8, is a schematic diagram of the circuit structure of a delay unit provided in an embodiment of the present application. As shown in the figure, the figure shows a switch tube D1, a capacitor C, a first resistor R1, and a second resistor R2. The specific connection relationship is that the control end of the switch tube D1 is connected to the output end of the comparison unit, and the input end of the switch tube D1 is connected to the preset power supply; the first end of the capacitor C, the first end of the first resistor R1, and the first end of the second resistor R2 are all connected to the output end of the switch tube D1, the second end of the capacitor C and the second end of the first resistor R1 are grounded, and the second end of the second resistor R2 is connected to the control unit.

[0081] The specific circuit function is: Figure 8 When the control terminal of the middle switch D1 receives the first signal, the switch D1 switches from the on state to the off state. Because the voltage across capacitor C cannot change suddenly, capacitor C discharges to ground and to the control unit connected to the R2 branch through R1. As capacitor C continues to discharge until the voltage across capacitor C is less than the trigger voltage of the control unit, the control unit controls the first switch module to disconnect the power battery from the power module. It can be understood that the second signal described in this embodiment is the voltage across capacitor C.

[0082] based on Figure 8 As can be seen from the circuit principle diagram of the delay unit shown, the preset time length is set by setting the resistance values of the first resistor R1 and the second resistor R2.

[0083] The specific preset duration can be determined by the following formula.

[0084] Preset duration: τ = (R1 / / R2) * C / I. Where τ is the preset duration, R1 is the first resistor, R2 is the second resistor, C is the capacitance, and I is the discharge current. R1 / / R2 represents the parallel operation of the first and second resistors.

[0085] Of course, in practical applications, Figure 8 The circuit structure of the delay unit shown is only an exemplary description. Those skilled in the art can also set other circuit structures to delay the disconnection of the circuit according to actual needs, such as setting a timer circuit (digital control circuit), etc. This application does not impose specific restrictions on this.

[0086] In a possible implementation, the control unit mentioned above specifically includes a switch tube, wherein the input end of the switch tube is electrically connected to the control end of the first switch module; the output end of the switch tube is grounded; and the control end of the switch tube is connected to the delay unit.

[0087] It is understood that the switch tube in the control unit is used to control the conduction and shutdown of the circuit. In one possible implementation, the switch tube in the control unit can specifically be a thyristor. Of course, those skilled in the art can also select other circuit devices and set other circuit structures as the switch tube in the control unit according to actual needs, and this application does not impose specific limitations on this.

[0088] Second, the first switch module.

[0089] See also Figure 9 , is a schematic diagram of the circuit structure of a first switch module provided in an embodiment of the present application. As shown in the figure, in order to clearly illustrate the function of the first switch module, Figure 9 In addition to the circuit structure of the first switch module, the control unit is also shown. As shown, the first switch module includes a relay K-S1. The control coil K of relay K-S1 is connected to the control unit, the first terminal of relay K-S1 is connected to the power battery, and the second terminal of relay K-S1 is connected to the power module.

[0090] The input and output terminals of the control unit and the control coil K of the relay K-S1 are connected in series between the preset power supply and the ground; the control terminal of the control unit is connected to the delay unit. Figure 9 The control unit in the circuit is shown as thyristor VS1, and the preset power supply is +12V.

[0091] It can be understood that when the voltage at the first end of the relay is less than the voltage at the second end of the relay and the duration meets the preset time length, the thyristor VS1 is controlled to be disconnected, thereby causing the relay to disconnect the electrical connection between the power battery and the power module.

[0092] Of course, constructing the first switch module based on the relay is only an exemplary description. Relevant technicians in this field can set other circuit structures to realize the function of the first switch module according to actual needs, and this application does not impose specific restrictions on this.

[0093] It should be noted that the first end of the relay is the first end of the first switch module, and the second end of the relay is the second end of the first switch module. When the relay is turned on, the power battery supplies power to the inverter through the relay, causing the inverter to drive the motor to rotate.

[0094] It can be understood that the first switch module composed of relays can effectively disconnect the electrical connection between the inverter and the power battery, thereby effectively protecting the relevant components in the circuit and improving the user's driving safety.

[0095] In this embodiment of the present application, by connecting a first switch module between the inverter and the power battery and using a control module to precisely regulate its on and off states, reverse current caused by the accumulation of electromotive force from the high-voltage busbar can be effectively suppressed. This design controls the predetermined duration of conduction between the power battery and the power module, allowing the reverse Ampere force generated by the reverse current to reduce the motor's speed and mitigate the accumulation of reverse electromotive force. By blocking the reverse current path, it prevents current backflow from damaging critical components such as the IGBT due to excessive reverse electromotive force.

[0096] In one possible implementation, the electrical connection between the power battery and the inverter also includes a second path, namely, a second switch module. Specifically, the first end of the second switch module is used to connect to an external power battery, and the second end of the second switch module is used to connect to an external power module. Specifically, when the voltage at the first end of the second switch module is less than the voltage at the second end of the second switch module, the second switch module is controlled to be disconnected; when the voltage at the first end of the second switch module is greater than or equal to the voltage at the second end of the second switch module, the electrical connection between the power battery and the power module is restored.

[0097] It is understandable that since the first switch module has a lower current carrying capacity and the second switch module has a higher current carrying capacity, when the power battery is driving the motor normally, the second switch module can be controlled to be turned on, and the power battery mainly supplies power to the power module through the second switch module, ensuring the normal operation of the motor.

[0098] In one possible implementation, the second switch module is specifically a second thyristor. A first end of the second thyristor is connected to the power battery, a second end of the second thyristor is connected to the power module, and a control end of the second thyristor is connected to an electronic control unit (ECU).

[0099] Specifically, since the thyristor cannot conduct in the reverse direction during normal operation, when the voltage at the first terminal of the second thyristor is less than the voltage at the second terminal of the second thyristor, the power module cannot charge the power battery through the second thyristor; when the control terminal of the second thyristor receives a control signal sent by the ECU and the voltage at the first terminal of the second thyristor is greater than or equal to the voltage at the second terminal of the second thyristor, the second thyristor conducts the electrical connection between the power battery and the power module.

[0100] It is understandable that since the current carrying capacity of the first switch module is low and the current carrying capacity of the second thyristor is high, the second thyristor can be controlled to be turned on, and the power battery mainly supplies power to the power module through the second switch module to ensure the normal operation of the motor.

[0101] Of course, in actual applications, the second switch module based on the second thyristor is only an exemplary description. Those skilled in the art can also set other circuit structures according to actual needs to implement the corresponding functions of the second switch module. This application does not impose specific restrictions on this.

[0102] For ease of understanding, the present application embodiment provides a schematic diagram of the motor open circuit protection circuit structure. Figure 10 , is a schematic diagram of the structure of another motor open circuit protection circuit provided by an embodiment of the present application. As shown in the figure, a comparison unit 501, a delay unit 502, a control unit 503, a first switch module 401 and a second switch module 1001 are shown.

[0103] As shown in the figure, the comparison unit 501 specifically includes: a comparator A, a third resistor R3 to a ninth resistor R9. Among them, the first end of the third resistor R3 is electrically connected to the 12V power supply; the second end of the third resistor R3 is electrically connected to the first end of the fourth resistor R4, and the second end of the fourth resistor is grounded; the output end of the comparator A is electrically connected to the node between the third resistor R3 and the fourth resistor; the positive power supply end of the comparator A is electrically connected to the second end of the fifth resistor R5; the first end of the fifth resistor R5 is electrically connected to the 12V power supply; the negative power supply end of the comparator A is grounded; the first end of the sixth resistor R6 is connected to the inverter; the first end of the eighth resistor R8 is electrically connected to the positive electrode of the power battery; the second end of the eighth resistor R8 is electrically connected to the first end of the ninth resistor R9; the second end of the ninth resistor R9 is electrically connected to the negative electrode of the power battery; the second end of the sixth resistor R6 is electrically connected to the first end of the seventh resistor R7; the second end of the seventh resistor R7 is electrically connected to the negative electrode of the power battery; the non-inverting input end of the comparator A is electrically connected to the node between the eighth resistor R8 and the ninth resistor R9; and the inverting input end of the comparator A is electrically connected to the node between the sixth resistor R6 and the seventh resistor R7.

[0104] The delay unit 502 specifically includes: a switch D1, a capacitor C1, a first resistor R1, and a second resistor. The second end of the second resistor R2 is electrically connected to the control end of the control unit 503; the first end of the second resistor R2 is electrically connected to the first end of the first resistor R1; the second end of the first resistor R1 is grounded; the first end of the capacitor C1 is electrically connected to the node between the first resistor R1 and the second resistor R2; the second end of the capacitor C1 is grounded; the source of the switch D1 is electrically connected to the node between the first resistor R1 and the second resistor R2; the drain of the switch D1 is electrically connected to a 12V power supply; and the gate of the switch D1 is electrically connected to the output end of the comparator A.

[0105] The control unit 503 specifically includes: a first thyristor VS1 , wherein the output terminal of the first thyristor VS1 is grounded; the control terminal of the first thyristor VS1 is electrically connected to the second terminal of the second resistor R2 ; and the input terminal of the first thyristor VS1 is electrically connected to the coil output terminal of the relay K-S1 .

[0106] The first switch module 401 specifically includes a relay K-S1. The first terminal of the relay K-S1 is electrically connected to the positive electrode of the power battery; the second terminal of the relay K-S1 is electrically connected to the first terminal of the inverter; the coil output terminal of the relay K-S1 is electrically connected to the input terminal of the first thyristor VS1; and the coil input terminal of the relay K-S1 is electrically connected to the 12V power supply.

[0107] The second switch module 1001 specifically includes: a second thyristor VS2, wherein the input end of the second thyristor VS2 is electrically connected to the positive electrode of the power battery; the second end of the second thyristor VS2 is electrically connected to the first end of the inverter; and the control end of the second thyristor VS2 is electrically connected to the ECU.

[0108] Specifically, under normal power supply conditions, the second thyristor VS2 is in the on state, and the voltage at the positive terminal of the power battery is greater than or equal to the voltage at the first terminal of the inverter. At this point, voltage comparator A outputs a high level. Then, after the 12V power supply is divided by the third resistor R3 and the fourth resistor R4, a higher voltage is generated at the gate of the switch D1, providing a stable bias voltage for the switch D1, turning it on. At this point, the control terminal of the first thyristor VS1 is connected to the 12V power supply via the second resistor R2 and is in the on state. The control coil of relay K-S1 is energized, and the switch contact S1 of relay K-S1 is closed, allowing the power battery to supply power to the inverter. Simultaneously, the 12V power supply also charges capacitor C1.

[0109] When the controller controls the inverter to enter the open-circuit protection state and the motor speed is high, the second thyristor VS2 is subjected to reverse voltage and cannot conduct in the reverse direction, and will be in the cut-off state. Because the voltage at the positive terminal of the power battery is lower than the voltage at the inverter terminal, the voltage comparator A will output a low level; the gate of the switch tube D1 will be forced to ground, and the switch tube D1 will be in the cut-off state. At this time, because the voltage across the capacitor C1 cannot change suddenly, it will discharge through the first resistor R1, the second resistor R2, and the first thyristor VS1. Therefore, the first thyristor VS1 will continue to conduct until the voltage of the capacitor C1 is lower than the gate conduction threshold of the first thyristor. At this time, the first thyristor VS1 will turn off, the control coil of the relay K-S1 will be de-energized, and the switch contact S1 of the relay K-S1 will be opened.

[0110] During the delayed disconnection of relay K-S1, that is, when switch contact S1 has not yet disconnected, the back electromotive force generated by the motor is higher than the power battery voltage, which will reversely charge the power battery through the IGBT's freewheeling diode. This will in turn generate an Ampere force inside the motor that hinders its rotation, providing a reverse braking torque to the motor to hinder its rotation. Therefore, the motor speed can be reduced within this preset duration. When the first switch module disconnects the electrical connection between the power battery and the power module, the motor's low speed can prevent the accumulation of high electromotive force at the power module, reducing the risk of circuit breakdown and improving circuit safety.

[0111] Corresponding to the above embodiments, this application also provides a motor drive system. Specifically, it includes a power battery, a motor open-circuit protection circuit, and a power module. The power battery outputs direct current (DC), while the power module receives the DC power from the power battery through the open-circuit protector and converts it into alternating current (AC) to drive the motor.

[0112] For details, please refer to the detailed description of the above embodiments in this article. For the sake of brevity, this application will not go into details.

[0113] Corresponding to the above-mentioned embodiments, the present application further provides a vehicle. The vehicle includes the motor drive system described above. The specific functions can be found in the detailed description of the above-mentioned embodiments herein. For the sake of brevity, this application does not elaborate on them in detail.

[0114] In the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0115] Those skilled in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented using a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0116] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0117] In this specification, reference can be made to the same or similar parts between the various embodiments. In particular, for the device embodiment and the terminal embodiment, since they are basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description in the method embodiment.

Claims

1. A motor open circuit protection circuit, characterized in that: include: a first switch module, wherein a first end of the first switch module is used to connect to a power battery, and a second end of the first switch module is used to connect to a power module; A control module, connected to the control end of the first switch module, and configured to: When it is detected that the voltage at the first terminal of the first switch module is less than the voltage at the second terminal thereof and the duration meets a preset time length, the first switch module is controlled to disconnect the electrical connection between the power battery and the power module.

2. The motor open circuit protection circuit according to claim 1, characterized in that: The control module includes a comparison unit, a delay unit and a control unit connected in sequence; wherein, The first input end of the comparison unit is connected to the first end of the first switch module, and the second input end of the comparison unit is connected to the second end of the first switch module; The comparison unit is configured to: When the voltage at the first end of the first switch module is less than the voltage at the second end of the first switch module, output a first signal; The delay unit is configured as follows: When the first signal is received and the first signal lasts for the preset time period, outputting a second signal; The control unit is configured to: After receiving the second signal, the first switch module is controlled to disconnect the power battery and the power module.

3. The motor open circuit protection circuit according to claim 2, characterized in that: The first switch module includes a relay, a control coil of the relay is connected to the control unit, a first end of the relay is connected to the power battery, and a second end of the relay is connected to the power module.

4. The motor open circuit protection circuit according to any one of claims 2 to 3, characterized in that: The comparison unit includes a comparator, a non-inverting input end of the comparator is connected to the first end of the first switch module, an inverting input end of the comparator is connected to the second end of the first switch module, and an output end of the comparator is connected to the delay unit.

5. The motor open circuit protection circuit according to any one of claims 2 to 3, characterized in that: The delay unit includes a switch tube, a capacitor, a first resistor and a second resistor; the control end of the switch tube is connected to the output end of the comparison unit, and the input end of the switch tube is connected to a preset power supply; The first end of the capacitor, the first end of the first resistor and the first end of the second resistor are all connected to the output end of the switching tube, the second end of the capacitor and the second end of the first resistor are grounded, and the second end of the second resistor is connected to the control unit.

6. The motor open circuit protection circuit according to claim 3, characterized in that: The control unit includes a switch tube, the input end and the output end of the switch tube and the control coil of the relay are sequentially connected in series between a preset power supply and ground, and the control end of the switch tube is connected to the delay unit.

7. The motor open circuit protection circuit according to claim 1, characterized in that: The motor open circuit protection circuit further includes a second switch module, a first end of the second switch module is used to connect to the power battery, and a second end of the second switch module is used to connect to the power module; The second switch module is configured as follows: When the voltage at the first terminal of the second switch module is greater than or equal to the voltage at the second terminal of the second switch module, conducting the electrical connection between the power battery and the power module; When the voltage at the first terminal of the second switch module is lower than the voltage at the second terminal of the second switch module, the electrical connection between the power battery and the power module is disconnected.

8. The motor open circuit protection circuit according to claim 7, characterized in that: The second switch module includes a thyristor.

9. A motor drive system, comprising a power battery and a power module, characterized in that: Also includes: The motor open circuit protection circuit according to any one of claims 1 to 8; The motor open circuit protection circuit is connected between the power battery and the power module.

10. A vehicle, characterized in that: Comprising the motor drive system as claimed in claim 9.

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