Introduction to the internal structure and principles
of new energy vehicles
New energy vehicles mainly comprise power battery systems, electric drive systems, vehicle controllers, charging systems, chassis systems, auxiliary systems, bodies, etc. Among them, the battery, motor, and electronic control systems are the core components of the big three electrics, responsible for the power source and driving control of new energy vehicles. The vehicle controller is the brain of the car and the system control center. It processes all input information and sends the operating status information of the motor control system to the vehicle controller. The vehicle controller cooperates with the power system BMS to generate power feedback, so that the power battery system can be reversely charged, etc. The chassis system is responsible for the vehicle's driving, steering, and braking functions and for ensuring the normal driving and safety of the vehicle.
The drive motor system is one of the three core systems of electric vehicles and is the main driving system for vehicle driving. Its characteristics determine the main performance indicators of the vehicle and directly affect the vehicle's power, economy, and user driving experience.
The electric drive system is mainly composed of a motor, a motor controller MCU, and a mechanical transmission device. Its structural form directly affects the layout of the electric vehicle drive system. The motor controller controls the speed, torque and rotation direction of the drive motor according to the instructions of the vehicle controller VCU, the speed of the drive motor and the current feedback signal. The motor is required to assume the dual functions of electric and power generation in pure electric vehicles, that is, to play its main electric function during normal driving and convert electrical energy into mechanical rotational energy; and to generate electricity during deceleration and downhill gliding, to assume the function of a generator and convert the inertial kinetic energy of the wheel into electrical energy.
The vehicle control system usually adopts a hierarchical control architecture: the vehicle controller is the first layer, responsible for overall control, coordinating the work and information processing of each control unit; other control units are the second layer, including motor controller, battery management system, on-board charger, DC/DC converter, instrument control unit, air conditioning control unit, steering control unit, brake control unit, etc. The input signals of the vehicle controller and each control unit are collected by the corresponding sensors.
The automobile braking system is to meet the braking safety requirements of the automobile during use, with good braking performance, easy operation and good braking smoothness. At present, pure electric vehicles are equipped with an electronic power steering system EPS as standard, which refers to a steering system that is controlled by electronic control with the help of electric motor power. The electric power steering system does not have the hydraulic pump, hydraulic pipeline, steering column valve body and other structures of the hydraulic power steering system. It is based on the original automobile steering system and has been modified and added with the following parts: EPS electronic control unit, torque and angle sensor, EPS motor, etc. The transmission mechanism of the steering system is driven by an electric motor, replacing the traditional mechanical hydraulic mechanism. It can provide real-time steering assistance to the driver in various environments.
Overview The internal components of new energy are quite complex and precise. The following are the main structures and their names.
1. Electric drive system
Motor: Converts electrical energy into mechanical energy to drive the vehicle forward. The motor is usually composed of components such as stator, rotor, bearing and sensor.
Inverter: Converts the direct current (DC) output by the battery into the alternating current (AC) required by the motor. The inverter contains electronic components such as IGBT, which realizes the conversion of electrical energy by adjusting the control signal.
Controller (VCU): As the "brain" of the electric vehicle, it is responsible for receiving the driver's instructions and controlling the operation of the electric drive system, including the speed, torque, and other parameters of the motor.
2. Power system
Battery pack: It is composed of multiple battery cells and is responsible for storing and providing electrical energy. The battery pack also contains a battery management system (BMS) to monitor the voltage, current, temperature, and other conditions of the battery to ensure the safe and efficient operation of the battery.
Charging system: It includes a charging interface, charger, and related control unit, which is used to convert the AC power of the external power supply into DC power to charge the battery pack.
3. Auxiliary system
Power steering system: It provides steering assistance to reduce the driving burden of the driver.
Air conditioning system: It includes an electric compressor, condenser, evaporator, and other components to adjust the temperature and humidity in the car.
Lighting and defrosting device: It includes headlights, taillights, fog lights, windshield defrosters, etc. to ensure driving safety and passenger comfort.
Wipers and radio: It provides clear vision and entertainment functions for driving on rainy days.
4. High-voltage wiring harness
Cables connecting high-voltage components such as battery packs, motors, inverters, etc. are used to transmit high voltage and high current. The design of a high-voltage wiring harness needs to consider factors such as electrical isolation, electromagnetic shielding, and safety.
5. Thermal management system
Includes cooling system and heating system, used to maintain the appropriate operating temperature of components such as battery pack and electric motor. The cooling system usually adopts liquid cooling or air cooling to dissipate heat by circulating coolant or air.
