Voltage to Frequency Speed Control of Induction Motor using Cascaded Multilevel inverter

In this paper a voltage to frequency speed control of an induction motor is presented. A cascaded multilevel inverter MLI with unequal dc sources used to drive the motor with minimum total harmonic distortion. The induction motor operates with approximately constant maximum torque by keeping V/f constant. The machine drive circuit is a cascaded multilevel inverter and the control strategy is simple and the motor current has low total harmonic distortion. The selection of both optimal values of dc sources and switching angles of cascaded multilevel inverter lead extra harmonics elimination depending on the number of levels. Simulation and theoretical analysis are presented for five levels inverter to drive induction motor with wide speed range. Practical results were validated the simulation results.