New topology of three phase soft switching inverter using a dual auxiliary circuit

Abstract

In current paper it is described a new topology of a three phase soft switching inverter. The aim is to develop a robust and practical soft switching inverter used in high power and high switching frequency applications. The presented topology is using coupled inductors and gives significant practical advantages when compared with similar topologies. The circuit can provide a mechanism by which the magnetization current passing the coupled inductor is reset. The new topology is also preventing the flow of free-wheeling currents generated in the main inverter into the auxiliary soft switching cell. These two parasitic effects can cause saturation of the magnetic core used for coupling the inductors. This mechanism is described on the steady-state stages and also simulations are provided to confirm the theoretical assumptions. The circuit has been simulated in SABER but also implemented in a prototype, while its performance is evaluated by test.