Electric vehicle control systems include vehicle control unit, battery management systems, and drive motor controllers.
Vehicle Control Unit
As the central control unit of electric vehicles, the vehicle control unit is the core of the entire control system and the control center of each subsystem. The main function of the VCU is to coordinate and manage the operating status of the entire vehicle, including collecting motor and battery status, collecting accelerator pedal signals, brake pedal signals, actuator and sensor signals, and making corresponding judgments based on comprehensive analysis of the driver's intentions, and then monitoring the controlling action of the lower layer components.
Drive motor controller
The main function of the motor controller is to receive torque message instructions from the vehicle controller, and then control the speed and direction of rotation of the drive motor. In addition, during the energy recovery process, the motor controller is also responsible for converting the AC power generated by the secondary torque of the drive motor, turning AC into DC and recharging to the power battery.
Battery Management System
Compared with the first two controllers, the battery management system is relatively simple. Its main functions include real-time monitoring of battery physical parameters, online diagnosis and alarm, charge, discharge and precharge control, equalization management and thermal management.
In terms of the modification design plan for the electric vehicle control system, our vehicle divides the entire vehicle electronic control system into two parts, a high-voltage control system and a low-voltage control system.
High-voltage Control System
In electric vehicles, high-voltage components include power batteries, drive motors, power distribution boxes (PDU), electric compressors, DC/DC, OBC, PTC, high-voltage wiring harnesses, etc. These components constitute the vehicle's high-voltage system, of which the battery pack and power battery management system, drive motor and motor control system, and high-voltage regulation system are the three core components of pure electric vehicles.
Battery pack and battery management system
The power source of electric vehicles is power batteries. The voltage of power batteries is mostly between 100 and 400V, and the output current can reach 300A. The capacity of the power battery affects the cruising range of the vehicle and also affects the charging time. The battery management system is responsible for the intelligent management of various parameters of the entire battery.
Drive motor and its controller
The motor controller converts high-voltage direct current into alternating current and interacts with other modules in the vehicle to achieve effective regulation of the drive motor. The drive motor works more efficiently, reaching more than 85%. Compared with traditional cars, its energy utilization rate is higher and it can reduce resource waste.
High-voltage power regulating system
The function of the high-voltage power regulation system is mainly realized through the high-voltage power distribution box. The high-voltage power distribution box is composed of many high-voltage relays and high-voltage fuses. There are also related chips built inside to realize signal communication with related modules to ensure the safety of high-voltage power consumption of the entire vehicle.
low-voltage power control system
The low-voltage electrical system of electric vehicles mainly consists of DC/DC power converters, auxiliary batteries and several low-voltage electrical equipment. The low-voltage electrical equipment of electric vehicles mainly includes lighting systems, instrument systems and entertainment systems. At present, low-voltage electrical systems usually use 12V/24V DC power supply as the vehicle's low-voltage power supply. On the one hand, it supplies conventional low-voltage electrical appliances such as lights and wipers, and on the other hand, it supplies power to vehicle controllers, motor control systems, battery management systems, and high-voltage equipment. Controller and cooling electric water pump and other auxiliary parts are powered by low voltage control system.