Improved current control technique for VSI PWM inverters with constant modulation frequency and extended voltage range

Abstract

A hysteresis control method for three-phase, current-controlled, PWM voltage-source-inverters (VSIs) is presented. The inverters are characterized by constant switching frequency. The method is based on a phase-interference minimization technique presented by the authors previously (1987) but avoids the need to know the load parameters. It minimizes the commutation losses and current ripple, while allowing maximum output AC voltage to be obtained from the inverter. The method exhibits all the favorable characteristics of hysteresis controls: fast response, good accuracy, and robustness.