The Software Design Of Controller For Extended Range Electric Vehicle

With the development of the society, the energy crisis and environmental pollution havebeen becoming more and more seriously. It’s necessary to develop a new type of transport forsaving energy and reducing pollution. For these reasons, extended range electric vehicle cameinto being. The vehicle control system is the key technology of extended range electricvehicle, which is related to the stable and efficient of the car. It plays a very important role inmotor running，range extender controlling，the charging and discharging process of thebattery，the network communication inside the vehicle, status monitoring, fault diagnosis andtreatment etc.In this paper, the overall design of the software has been presented for the controller ofextended range electric vehicle. Its software system takes a structured programming methodof functional decomposition from top to bottom, which decomposes the system into severalfunctional modules in order to reduce the workload and improve the reliability. First of all, thewhole system is divided into three modules, including control module, signal acquisition andcommunication module, security and fault diagnosis module. In addition, according to thetypes of work the control module is divided into three modes, including drive mode,extended-range mode and charging mode. The extended range model adopts the thermostatcontrol strategy to control the engine work in the best fuel economy zone, so that the engineoutput stable power. What’s more, signal acquisition and communication module consists ofthe communication module, signal acquisition and filtering processing module. This moduleuses a distributed communication system of extended range electric vehicle based on CANnode, and takes different filtering methods for different signal. Lastly, security and faultdiagnosis module is divided into the security module, fault diagnosis and processing module.This module has taken a brake-first strategy to ensure the security of the vehicle. In software,the Watchdog technology is used to make the system more reliable.On the work condition of NEDC, the simulation is carried out for the electric-only modeand extended range mode of extended range electric vehicle. The results of test show that thedesign of the control system structure is reasonable. The control system meets therequirements of control, communication and signal acquisition. To summarize, the controllerof vehicle not only worked securely, stably and reliably, but also improved the fuel efficiencyand reduced air pollution.