A novel series resonant ZCS full bridge three-level DC-AC inverter

A novel series resonant zero-current-switching (ZCS) full bridge three-level dc-ac inverter topology is presented in this paper by adopting low on-state resistance low D-S voltage switches. The operation mode in 1 and 2 quadrants are given in detail. Mathematical analysis is given based on circuit model in order to select resonant mode. The inverter can be operated by simple control logic. All the analysis and experimental result show that this new topology has the feature of reducing the voltage stress across the main switches to half of the input voltage and can achieve ZCS for all the switches. What the most important is that it can realize ZCS in the entire load range, even under no load. By using redundant resonant state, a novel control strategy is given, which can effectively control the neutral point voltage keeping half the DC bus voltage. The inverter can effectively control the power flow and has the character of low output voltage ripple