Electric wheelchair propulsion by induction motors

Abstract

This paper presents the design and implementation of a practical variable frequency induction motor propulsion system for electric wheelchairs. The power source is a 24 volt battery which is converted to three phase variable frequency voltage by means of a microcomputer controlled inverter. The frequency can be varied between 10 and 80 Hz, adequate for the speeds required in this type of system. The system was first tested in an open loop configuration. Then, a closed loop system was implemented in which the output and reference speed were compared for different load situations, and the error in speed was minimized by adjusting the frequency.