The vehicle controller is the central control unit for the normal operation of an electric vehicle. It is the core component of the vehicle control system and the main control component for functions such as normal operation, regenerative braking energy recovery, fault diagnosis and handling, and vehicle status monitoring of pure electric vehicles. So what are the functions of the vehicle control system for new energy vehicles? Let's find out below.
1. Functions for controlling vehicle movement
The electric motor in a new energy vehicle must output driving or braking torque according to the driver's intention. When the driver presses the accelerator or brake pedal, the electric motor must output a certain amount of driving power or regenerative braking power. The greater the pedal opening, the greater the output power of the electric motor. Therefore, the vehicle controller must interpret the driver's operation appropriately; receive feedback information from various subsystems of the vehicle to provide decision feedback to the driver; and send control commands to various subsystems of the vehicle to achieve normal vehicle operation.
2. Networked management of the entire vehicle
Modern automobiles contain numerous electronic control units and measuring instruments that exchange data. Ensuring fast, efficient, and trouble-free data transmission is a challenge. To address this, the German company Bosch developed the Controller Area Network (CAN) in the 1980s. In electric vehicles, the electronic control units are more numerous and complex than in traditional gasoline-powered vehicles, making the application of the CAN bus essential. The vehicle controller is one of many controllers in an electric vehicle and a node on the CAN bus. In vehicle network management, the vehicle controller is the central hub for information control, responsible for information organization and transmission, network status monitoring, network node management, and network fault diagnosis and handling.
3. Braking energy regenerative control
New energy vehicles use electric motors as the output mechanism for driving torque. These electric motors have regenerative braking capabilities, acting as generators to produce electricity using the braking energy of the electric vehicle. This energy is simultaneously stored in an energy storage device, and when charging conditions are met, it is fed back to the battery pack. During this process, the vehicle controller determines whether regenerative braking is possible at a given moment based on the opening of the accelerator and brake pedals and the state of charge (SOC) value of the battery. If possible, the vehicle controller sends a braking command to the motor controller to recover a portion of the energy.
4. Vehicle energy management and optimization
In pure electric vehicles, the battery powers not only the motor but also the electric accessories. Therefore, to achieve maximum driving range, the vehicle controller is responsible for the vehicle's energy management to improve energy utilization. When the battery's State of Charge (SOC) is low, the vehicle controller will issue commands to certain electric accessories to limit their output power, thereby increasing the driving range.
5. Vehicle status monitoring and display
The vehicle controller should monitor the vehicle's status in real time and send information from each subsystem to the onboard information display system. This process involves using sensors and the CAN bus to detect the vehicle's status and the status information of each subsystem, driving the display instruments to show the status information and fault diagnosis information. The displayed content includes: motor speed, vehicle speed, battery level, fault information, etc.
6. Fault Diagnosis and Handling
Continuously monitor the vehicle's electronic control system and perform fault diagnosis. The fault indicator light displays the fault type and some fault codes. Based on the fault details, promptly implement appropriate safety protection measures. For less serious faults, drive at low speed to the nearest repair shop for inspection.
7. External charging management
It enables charging connectivity, monitors the charging process, reports charging status, and signals when charging is complete.
8. Online diagnostics and offline testing of diagnostic equipment
It is responsible for connecting and communicating with external diagnostic equipment to implement UDS diagnostic services, including data stream reading, fault code reading and clearing, and control port debugging.
