A microprocessor based control system for an electric vehicle

The control system described in this thesis is a low cost system designed to control the speed of an electric vehicle by adjusting the speed of a compound wound DC motor. The speed control method developed in this system is a combination of battery tapping, for control of the armature voltage, and pulse width modulation for field control; both generated by a microprocessor. Using a microprocessor, the control system is readily adaptable to a variety of motor voltages and motor control techniques by modifying the internal firmware of the processor. Overcurrent protection is included to prolong battery and motor life. Regenerative braking is automatic upon release of the accelerator and has two levels for maximum energy recovery. A display of the remaining charge in the vehicle\u27s batteries has a continually powered memory to retain the information when the vehicle is parked. This display is also temperature compensated to reflect the characteristics of lead acid batteries over varying temperatures. The control system was installed in a test vehicle where it was debugged and evaluated