When a conventional high frequency IGBT-switched PWM inverter is used to drive motors with a long lead, one big concern is the voltage stress due to the surge voltage which may occur at the motor terminals. This paper proposes that such a surge voltage could be reduced by using a simple-controlled soft-switched PWM inverter to replace the conventional one as drives. By performing simulation and experiments, the authors have investigated the characteristics of the surge voltages involved in both conventional and soft-switched inverters. The results confirm that the surge voltages can be indeed reduced significantly when the soft-switched inverter is used.
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