A NEW MODULATION TECHNIQUE FOR A FOUR-SWITCH INVERTER FEEDING AC MOTOR

摘要

A new method to generate PWM signals to control Four-Switch 3-Phase Inverter (FSTPI) is presented. The method is based on direct flux and torque control, which is usually used with the classical inverter topology (B6) but never applied with the topology FSTPI. A new switching table has been derived, which selects the optimum inverter switching states to fulfil the torque and flux requirements. The modulation strategy provides quick response and accurate control of both stator flux and motor torque. Experimental results have verified the validity and effectiveness of the proposed method to obtain a high performance AC drive with reduced initial cost.