Vector and direct torque control of two induction motors fed by a single nine switch inverter

Abstract

Over the past few years, there has been increasing interest and activity in the field of power electronics and drives, to satisfy the demand of the industrial area where the need for low cost, compact, integrated and reduced component power converters is critical. Nine-switch inverter (NSI) is a compact dual-output inverter developed to control two AC loads with less switches. Induction motors are very important loads that can be driven independently using nine switch inverters because they are cheap, rugged and require less maintenance, due to these characteristics, they have dominated in the field of electromechanical energy conversion, Nowadays, a large number of induction motors are found in the industry. The nine-switch inverter can serve the role of the dual output inverter that has been used in the past few years for controlling two induction motors, the cost and switching losses can be reduced as the number of switches is reduced from twelve to nine switches only. In this context, two control techniques; indirect rotor field-oriented control and direct torque control, are investigated in this project to study the independency of control of the nine- switch inverter powered motors. Furthermore, the effectiveness of the developed controllers in separating between the flux and torque control will be checked. Simulations of these techniques are then carried out using MATLAB and the obtained results analyzed and discussed to confirm the validity of the proposed techniques.