Development of a High Efficiency Inverter without Audible Noise

Abstract

The proposed inverter combines two methods which can largely decrease the on-state and switching losses. The first method, by using a current transformer and a single transistor, makes possible to reduce the on-state loss to less than 1/3 of the usual Darlington transistor. The second method, by using the auxiliary commutation IGBT in parallel with the transistor, makes possible the zero voltage switching resulting in no switching loss. To realize the higher inverter efficiency, snubber and its loss recovery circuit are employed. Three three-phase inverters were made experimentally to confirm the idea. Its volume and weight can be decreased to 1/3 than that of conventional three-phase inverter, and obtained the efficiency of 98.0% from 5kW to 20kW at switching frequency of 16kHz.