Explain the drive motor system of pure electric vehicles
The drive motor system is one of the three core systems of electric vehicles. It is the main drive system for vehicles. Its characteristics determine the main performance indicators of the vehicle, directly affecting the vehicle's power, economy and user driving experience.
First, the introduction of the drive motor system
The drive motor system consists of a drive motor and a drive motor controller (MCU). It is connected to other systems of the vehicle through high and low voltage harnesses and cooling lines.
The vehicle controller (VCU) sends commands to the motor controller MCU through the CAN network according to the accelerator pedal, brake pedal, gear and other signals, and adjusts the torque output of the drive motor in real time to achieve idle speed, acceleration, energy recovery, etc. Features.
The motor controller can monitor its own temperature, motor operating temperature and rotor position in real time, and transmit relevant information to the vehicle controller VCU to adjust the pump and cooling fan to keep the motor working at the ideal temperature.
Drive motor specification parameters,
1, the drive motor
The permanent magnet synchronous motor is a typical driving motor (Fig. 2). It has the advantages of high efficiency, small size and high reliability. It is the actuator of the power system and converts electrical energy into mechanical energy carrier. It relies on a built-in resolver and temperature sensor to provide information on the operating status of the motor and send the motor operating status information to the MCU in real time.
The resolver detects the position of the rotor of the motor. After decoding by the resolver in the motor controller, the motor controller can know the current rotor position of the motor, thereby controlling the corresponding IGBT power tube to conduct, energizing the three coils in sequence, and driving the motor. Rotate.
2, drive motor controller
The internal three-phase two-level voltage source inverter is the control core of the drive motor system, called intelligent power module. It is based on IGBT (insulated gate bipolar transistor), supplemented by driver integrated circuit and main control. integrated circuit.
The MCU processes all input signals and sends the drive motor control system operating status information to the vehicle controller VCU via the CAN2.0 network. The drive motor controller contains a fault diagnosis circuit. When the motor is abnormal, after a certain condition is reached, it will activate an error code and send it to the VCU vehicle controller, and also store the fault code and related data.
The drive motor controller mainly relies on the current sensor (Fig. 6), voltage sensor and temperature sensor to monitor the running state of the motor, and adjust the voltage and current according to the corresponding parameters and other control functions. The current sensor is used to detect the actual current of the motor, including bus current and three-phase AC current. The voltage sensor is used to detect the actual voltage supplied to the motor controller, including the power battery voltage and the 12V battery voltage. The temperature sensor is used to detect the operating temperature of the motor control system, including the temperature of the IGBT module.
