Protection circuit for motor controller of electric automobile

Abstract

The invention provides a protection circuit for a motor controller of an electric automobile, which belongs to the technical field of circuit protection and comprises a switch module, a control module and a protection module, the switch module adopts a PMOS (P-channel Metal Oxide Semiconductor) tube, the drain electrode of the PMOS tube is connected with a power input end, and the source electrode of the PMOS tube is connected with a power output end. The control module comprises a PNP triode, a second resistor and a third resistor, the power supply input end is connected in series with the base electrode of the PNP triode through the first capacitor and the first resistor, the emitter electrode of the PNP triode is connected with the power supply output end, the collector electrode of the PNP triode is connected with the power supply output end through the second resistor, and the collector electrode of the PNP triode is grounded through the third resistor. The protection module adopts a first diode. The power input end is connected with the anode of the first diode through the first capacitor. The cathode of the first diode is connected with the power output end. The collector electrode of the PNP triode is connected with the power supply output end through a voltage stabilizing diode. The power output end is grounded through the second capacitor. The circuit plays a role in protection when the power supply is reversed.

Description

Technical Field

[0001] This invention belongs to the field of circuit protection technology. Specifically, this invention relates to a protection circuit for an electric vehicle motor controller. Background Technology

[0002] The electric motor is the core power source of an electric vehicle, and the safe and stable operation of its controller is crucial. Circuit protection, acting as a "shield" for the controller, can withstand various risks and is key to preventing equipment damage and ensuring reliable system operation.

[0003] Chinese Patent 101966819A provides an on-board charging protection device, charging protection method, and vehicle for electric vehicles. The device and method include: a motor controller connected to the vehicle motor, providing motor operation signals and controlling the motor to operate or shut down according to instructions; an on-board charger providing power connection signals; a battery pack connected to both the on-board charger and the motor controller, providing battery signals and charging or supplying power to the motor according to instructions; and a vehicle controller electrically and communicatively connected to the motor controller, the on-board charger, and the power battery pack, determining based on the signals provided by the motor controller, the on-board charger, and the power battery pack, and sending charging control command signals to the on-board charger and the motor controller.

[0004] Existing technology does not take into account the harm to the motor controller when the power supply is reversed, which can cause great harm to the stable operation of the motor controller. Summary of the Invention

[0005] The present invention aims to provide a protection circuit for an electric vehicle motor controller, so as to achieve the technical objective of protecting the motor controller when the power supply is reversed.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a protection circuit for an electric vehicle motor controller, comprising a switch module, a control module, and a protection module. The power input terminal is connected to the power output terminal through the switch module, the power input terminal is connected to the input terminal of the control module, the output terminal of the control module is connected to the input terminal of the switch module, and the power input terminal is connected to the power output terminal through the protection module.

[0008] The switching module uses a PMOS transistor.

[0009] The drain of the PMOS transistor is connected to the power input terminal, and the source of the PMOS transistor is connected to the power output terminal.

[0010] The control module includes a PNP transistor, a second resistor, and a third resistor.

[0011] The power input terminal is connected in series with the base of the PNP transistor via a first capacitor and a first resistor. The emitter of the PNP transistor is connected to the power output terminal. The collector of the PNP transistor is connected to the power output terminal via a second resistor. The collector of the PNP transistor is grounded via a third resistor.

[0012] The protection module uses a first diode.

[0013] The power input terminal is connected to the anode of the first diode via a first capacitor, and the cathode of the first diode is connected to the power output terminal.

[0014] The collector of the PNP transistor is connected to the anode of the Zener diode, and the cathode of the Zener diode is connected to the power output terminal.

[0015] The power output terminal is grounded through the second capacitor.

[0016] The technical effects of this invention are as follows:

[0017] (1) The present invention can protect the circuit when the power supply is reversed, and at the same time can provide power to prevent the load from losing power when the power supply has a negative pulse.

[0018] (2) This invention enables a stable and reliable power supply. By using the PNP transistor in its off-state state in conjunction with the voltage divider effect of the second and third resistors, the source voltage of the PMOS transistor is made greater than the gate voltage, ensuring stable conduction of the drain and source of the PMOS transistor and guaranteeing normal voltage output at the power supply output terminal. At the same time, the Zener diode can effectively limit the voltage between the source and gate of the PMOS transistor, preventing it from exceeding the maximum allowable voltage, significantly improving the safety and durability of the PMOS transistor and extending its service life.

[0019] (3) This invention provides fast and effective protection. Utilizing the characteristic that the voltage across the first capacitor cannot change abruptly, the PNP transistor is quickly turned on, which in turn causes the PMOS transistor to turn off quickly, disconnecting the power input from the output and preventing negative voltage input to the load, thus avoiding load damage. Furthermore, by adjusting the value of the first resistor, the base current of the PNP transistor can be adjusted, increasing its turn-on speed and accelerating the turn-off speed of the PMOS transistor. This further enhances the circuit's responsiveness and reliability in the face of negative voltage input, effectively reducing the risk of damage to the load and the circuit itself caused by negative voltage.

[0020] (4) When a negative pulse appears at the power input, this invention can balance the short-term normal operation of the load with the safety protection of the circuit. When a negative pulse is input, the PNP transistor quickly turns on, causing the PMOS transistor to turn off. At this time, the charge stored in the second capacitor can supply power to the load, ensuring that the load operates normally for a short period of time. After the negative pulse disappears, the charge stored in the first capacitor discharges to the power output terminal through the first diode. Since the voltage difference across the first diode is small, it will not exceed the withstand voltage of the emitter and collector of the PNP transistor, thereby achieving effective protection of the PNP transistor and ensuring that the circuit can quickly return to the normal positive power supply state.

[0021] (5) By cleverly utilizing the principle that the voltage across the first capacitor cannot change abruptly, this invention achieves rapid turn-on of the PNP transistor and rapid turn-off of the PMOS transistor, ensuring that the charge of the second capacitor, which serves as a supporting capacitor, will not be discharged by a voltage with a negative pulse, thus maintaining the normal function of the second capacitor and enhancing the overall energy maintenance capability and working stability of the circuit.

[0022] (6) The present invention has a simple structure and efficient collaborative operation of each module. While realizing multiple protection functions, it has the advantages of fast response speed, convenient adjustment and high reliability. It significantly improves the safety and stability of the electric vehicle motor controller and reduces the probability of equipment failure caused by abnormal voltage. At the same time, it uses discrete components to build the circuit, which is convenient to purchase and has low cost. It has high practical value and promotion significance. Attached Figure Description

[0023] This manual includes the following figures, which illustrate the following:

[0024] Figure 1 This is a logic block diagram of a protection circuit for an electric vehicle motor controller according to the present invention.

[0025] Figure 2 This is a circuit diagram of a protection circuit for an electric vehicle motor controller according to the present invention;

[0026] Figure 3 This is a circuit simulation diagram of the electric vehicle motor controller protection circuit of the present invention when the power input is a positive voltage;

[0027] Figure 4 This is a circuit simulation diagram of the electric vehicle motor controller protection circuit of the present invention when the power input is a negative voltage;

[0028] Figure 5 This is a circuit simulation diagram of a protection circuit for an electric vehicle motor controller according to the present invention when a negative pulse occurs at the power input.

[0029] Figure 1 The following modules are marked as follows: 1. Switch module; 2. Control module; 3. Protection module. Detailed Implementation

[0030] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention, and to facilitate its implementation.

[0031] This invention provides a protection circuit for an electric vehicle motor controller, including a switch module, a control module, and a protection module. The power input terminal is connected to the power output terminal through the switch module, the power input terminal is connected to the input terminal of the control module, the output terminal of the control module is connected to the input terminal of the switch module, and the power input terminal is connected to the power output terminal through the protection module.

[0032] The switching module uses PMOS transistors. The drain of the PMOS transistor is connected to the power input terminal, and the source of the PMOS transistor is connected to the power output terminal.

[0033] The control module includes a PNP transistor, a second resistor, and a third resistor. The power input terminal is connected to the base of the PNP transistor in series with a first capacitor and a first resistor. The emitter of the PNP transistor is connected to the power output terminal. The collector of the PNP transistor is connected to the power output terminal through the second resistor. The collector of the PNP transistor is grounded through the third resistor.

[0034] The protection module uses a first diode. The power input terminal is connected to the anode of the first diode through a first capacitor, and the cathode of the first diode is connected to the power output terminal.

[0035] The collector of the PNP transistor is connected to the anode of the Zener diode, and the cathode of the Zener diode is connected to the power output terminal. The power output terminal is grounded through a second capacitor.

[0036] The present invention provides a protection circuit for an electric vehicle motor controller.

[0037] The present invention provides a protection circuit for an electric vehicle motor controller, comprising a switching module, a control module, and a protection module, wherein the switching module uses a PMOS transistor to control the opening and closing of the power output.

[0038] The control module includes a PNP transistor, a second resistor, and a third resistor. When the PNP transistor is off, the voltage divider effect of the second and third resistors causes the source voltage of the PMOS transistor to be greater than the gate voltage, thus turning on both the drain and source of the PMOS transistor. When the PNP transistor is on, the source and gate voltages of the PMOS transistor are the same, thus turning off both the drain and source of the PMOS transistor.

[0039] The protection module uses a first diode to cut off the reverse power supply and release the charge in the first capacitor to the power output terminal after the load pulse disappears.

[0040] The connection relationship of the electric vehicle motor controller protection circuit of the present invention is described in detail below.

[0041] like Figure 2 As shown, the drain of the PMOS transistor (M1) is connected to the power input terminal (VIN), the source of the PMOS transistor (M1) is connected to the power output terminal (VOUT), and the gate of the PMOS transistor (M1) is connected to the collector of the PNP transistor (Q1). The power input terminal (VIN) is connected to the base of the PNP transistor (Q1) in series through the first capacitor (C1) and the first resistor (R1). The emitter of the PNP transistor (Q1) is connected to the power output terminal (VOUT), and the collector of the PNP transistor (Q1) is connected to the third resistor (R1). 3) Grounding: The collector of the PNP transistor (Q1) is connected to the power output terminal (VOUT) through the second resistor (R2). The collector of the PNP transistor (Q1) is connected to the anode of the Zener diode (D2). The cathode of the Zener diode is connected to the power output terminal (VOUT). The power input terminal (VIN) is connected to the anode of the first diode (D1) through the first capacitor (C1). The cathode of the first diode (D1) is connected to the source of the PMOS transistor (M1). The power output terminal (VOUT) is grounded through the second capacitor (C2).

[0042] The working process of a protection circuit for an electric vehicle motor controller according to the present invention is described in detail below.

[0043] When the power input is positive, the voltage difference across the capacitor does not change abruptly, so the input voltage is quickly conducted to the other end of the capacitor. At this time, the voltages across the first capacitor are equal, and the emitter voltage of the PNP transistor is not greater than the base voltage. Therefore, the emitter and collector of the PNP transistor are not conducting. The PMOS transistor transmits voltage to the power output terminal through its body diode. The voltage at the output terminal, through the voltage divider of the second and third resistors, makes the source voltage of the PMOS transistor greater than the gate voltage. Once the voltage difference between the source and gate exceeds the turn-on voltage of the PMOS transistor, the drain and source conduct. The first diode prevents power from flowing from the power output terminal to the power input terminal through the first capacitor, and the Zener diode protects the source and gate voltages of the PMOS transistor from exceeding the maximum allowable voltage. Figure 3 This is a circuit simulation diagram when the power input is a positive voltage.

[0044] When the power input is negative, since the voltage difference across the capacitor does not change abruptly, the input voltage is quickly conducted to the other end of the capacitor. At this time, the voltage across the first capacitor is equal, the first diode is reverse-biased and cut off, the emitter voltage of the PNP transistor is greater than the base voltage, the emitter and collector of the PNP transistor are conducting, the body diode in the PMOS transistor is reverse-biased and cut off, the source voltage of the PMOS transistor is equal to the gate voltage, and the drain and source of the PMOS transistor are turned off. At this time, the load connected to the power output is disconnected, preventing damage to the load. In this invention, the base current of the PNP transistor can be adjusted by changing the value of the first resistor, thereby increasing the turn-on speed of the PMOS transistor and thus increasing the turn-on speed of the PNP transistor. This invention utilizes the principle that the voltage across the first capacitor cannot change abruptly to quickly turn on the collector and emitter of the PNP transistor, thereby turning off the source and drain of the PMOS transistor, and ensuring that the charge of the second capacitor, which serves as a supporting capacitor, is not discharged by a voltage carrying a negative pulse. Figure 4 This is a circuit simulation diagram when the power input is a negative voltage.

[0045] When a negative pulse appears at the power input, the input voltage is quickly conducted to the other end of the capacitor because the voltage difference across the capacitor does not change abruptly. At this time, the voltages across the first capacitor are equal, the first diode is reverse-biased and cut off, the emitter voltage of the PNP transistor is greater than the base voltage, and the emitter and collector of the PNP transistor are conducting. The body diode of the PMOS transistor is reverse-biased and cut off, the source voltage of the PMOS transistor is equal to the gate voltage, and the drain and source of the PMOS transistor are turned off. At this time, the charge stored in the second capacitor supplies power to the load connected to the power output terminal, but does not discharge to the power input terminal through the PMOS transistor. The load operates normally for a short period of time. After the negative pulse disappears, the charge stored in the first capacitor discharges to the power output terminal through the first diode. The voltage difference across the first diode is small, ensuring that it does not exceed the emitter and collector withstand voltage of the PNP transistor, thus protecting the PNP transistor. After this, the normal forward power supply phase begins. Figure 5 This is a circuit simulation diagram when a negative pulse appears at the power input.

[0046] This invention can protect the motor controller when the power supply is reversed, and at the same time can provide power to prevent the motor controller from losing power when a negative pulse occurs.

[0047] This invention enables stable and reliable power supply. By utilizing the off-state of the PNP transistor in conjunction with the voltage divider effect of the second and third resistors, the source voltage of the PMOS transistor is made greater than the gate voltage, ensuring stable conduction of the PMOS transistor's drain and source, and guaranteeing normal voltage output at the power supply terminal. Simultaneously, the Zener diode effectively limits the voltage between the PMOS transistor's source and gate, preventing it from exceeding the maximum allowable voltage, significantly improving the safety and durability of the PMOS transistor's operation and extending its service life.

[0048] This invention provides rapid and effective protection. Utilizing the characteristic that the voltage across the first capacitor cannot change abruptly, the PNP transistor is quickly turned on, which in turn causes the PMOS transistor to turn off quickly, disconnecting the power input and output terminals and preventing negative voltage input to the load terminal from causing damage. Furthermore, by adjusting the value of the first resistor, the base current of the PNP transistor can be adjusted, increasing its turn-on speed and thus accelerating the turn-off speed of the PMOS transistor. This further enhances the circuit's responsiveness and reliability in the face of negative voltage input, effectively reducing the risk of damage to the load and the circuit itself caused by negative voltage.

[0049] This invention balances short-term normal operation of the load with circuit safety protection when a negative pulse occurs at the power input. When a negative pulse is input, the PNP transistor quickly turns on, turning off the PMOS transistor. At this time, the charge stored in the second capacitor can supply power to the load, ensuring normal operation of the load for a short period. After the negative pulse disappears, the charge stored in the first capacitor discharges to the power output terminal through the first diode. Because the voltage difference across the first diode is small, it will not exceed the withstand voltage of the PNP transistor's emitter and collector, thus effectively protecting the PNP transistor and ensuring that the circuit can quickly return to normal forward power supply.

[0050] This invention cleverly utilizes the principle that the voltage across the first capacitor cannot change abruptly, thereby enabling the rapid turn-on of the PNP transistor and the rapid turn-off of the PMOS transistor. This ensures that the charge of the second capacitor, which serves as a supporting capacitor, will not be discharged by a voltage carrying a negative pulse, maintaining the normal function of the second capacitor and enhancing the overall energy retention capability and operational stability of the circuit.

[0051] This invention features a simple structure and efficient collaborative operation of its modules. While achieving multiple protection functions, it also boasts advantages such as fast response speed, convenient adjustment, and high reliability. It significantly improves the safety and stability of electric vehicle motor controllers, reduces the probability of equipment failure due to voltage anomalies, and uses discrete components to build the circuit, making it easy to purchase and cost-effective. Therefore, it has high practical value and promotional significance.

[0052] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A protection circuit for an electric vehicle motor controller, characterized in that: It includes a switch module, a control module, and a protection module. The power input terminal is connected to the power output terminal through the switch module. The power input terminal is connected to the input terminal of the control module. The output terminal of the control module is connected to the input terminal of the switch module. The power input terminal is connected to the power output terminal through the protection module.

2. The electric vehicle motor controller protection circuit as described in claim 1, characterized in that: The switching module uses a PMOS transistor.

3. A protection circuit for an electric vehicle motor controller as described in claim 1 or 2, characterized in that: The drain of the PMOS transistor is connected to the power input terminal, and the source of the PMOS transistor is connected to the power output terminal.

4. The electric vehicle motor controller protection circuit as described in claim 1, characterized in that: The control module includes a PNP transistor, a second resistor, and a third resistor.

5. A protection circuit for an electric vehicle motor controller as described in claim 1 or 4, characterized in that: The power input terminal is connected in series with the base of the PNP transistor via a first capacitor and a first resistor. The emitter of the PNP transistor is connected to the power output terminal. The collector of the PNP transistor is connected to the power output terminal via a second resistor. The collector of the PNP transistor is grounded via a third resistor.

6. The electric vehicle motor controller protection circuit as described in claim 1, characterized in that: The protection module uses a first diode.

7. A protection circuit for an electric vehicle motor controller as described in claim 1 or 6, characterized in that: The power input terminal is connected to the anode of the first diode via a first capacitor, and the cathode of the first diode is connected to the power output terminal.

8. A protection circuit for an electric vehicle motor controller as described in claim 1 or 4, characterized in that: The collector of the PNP transistor is connected to the anode of the Zener diode, and the cathode of the Zener diode is connected to the power output terminal.

9. The electric vehicle motor controller protection circuit as described in claim 1, characterized in that: The power output terminal is grounded through the second capacitor.

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