Research And Development Of Control System For Range Extender Of An Electric Vehicle

In recent years, a lot of vehicles have been made, which brings great energy andenvironmental burdens. Electric vehicle is paid to a lot of attention because of usingelectricity as power source and achieving ‘zero emissions’. However, the electricvehicle in a short time cannot be widely used due to the low energy density of thebattery. The auxiliary power unit added in the extended-range electric vehicle greatlyreduces the requirement for the battery capacity, and also reduces the dependence onfossil fuels for traditional vehicle.A range extender has been designed in this thesis based on a civil alternator whichcontains a small gasoline engine and a generator. The electrical part of the originalalternator is removes and the engine and generator are kept. Then, the control unit isdesigned including hardware design and control strategy design.Range extender control system hardware design includes MC9S12DP256Bminimum system circuit,5V and9V power supply circuit, the input signal processingcircuit, the actuator drive circuit, communication circuit, PCB board overall design. Thesoftware design contains bottom-driven design and top-level control algorithms design.The main bottom-driven design includes AD acquisition, actuator drive, speed signalacquisition and communication module design. Top-level algorithm mainly includesstartup/shutdown time, startup operation condition and steady-state operation condition.Finally, the control system is tested on the bench. The results show that the throttlehas a good dynamic response and can meet the requirements; during startup operationcondition, the choke and the throttle can work together very well; the stability of enginespeed has been greatly improved by optimization and can meet the design requirements.