OPEN-LOOP VARIABLE VOLTAGE VARIABLE FREQUENCY CONTROL OF THREE (3) PHASE INDUCTION MOTOR FOR AN ELECTRIC VEHICLE DRIVE

ABSTRACT

This work presented an open loop variable voltage variable frequency (V/F) control of three phase induction motor for an electric vehicle drive. The major advantage of v/f is the ease of implementation. Simulation and practical implementation of the project was carried out using sequential logic circuit for the control of the three phase inverter. Also included in the design is a 120V to 600V boost converter that increases the battery supply voltage to be able to supply the 420V induction motor. The v/f concept was implemented using NE555 to produce a square wave of 1000Hz, which was reduced to 100Hz by the help of the decade counter and was further divided by the flip-flop to obtain a maximum frequency of 50Hz. The results obtained shows that when there is linearity between the voltage and frequency, that maximum constant torque is always produced, thus agreeing with the concept of v/f control of induction motor.