Instantaneous current and voltage control strategy in low-pass filter based sine-wave voltage DC/AC converter topology for adjustable speed PWM drive system

Abstract

The paper describes work on the development of a topology and control of a three-phase DC/AC PWM converter for an adjustable speed cage induction motor drive system. It is shown that the proposed instantaneous feedback control method of the PWM converter with the low-pass LC filter effectively reduces high frequency harmonics which can damage the motor bearings and insulation. The proposed control technique of the converter with instantaneous LC filter current and voltage feedback loops, is very effective in reducing the switching frequency component and provides high quality sine-wave variable frequency and amplitude voltage to the motor. Experimental verification of the proposed topology and control strategy is provided with 2.2 kW laboratory drive system with conventional cage induction motor. The high quality sinusoidal output voltage from proposed converter at different motor speeds is presented.