Class DE Inverter with Asymmetric Shunt Capacitors

This paper presents a class DE inverter with asymmetric shunt capacitors. Generally the shunt capacitors of class DE inverter are equally given to the two switching devices. The input current from the dc power source flows into the upper shunt capacitor during the dead time. Therefore, the minimization of the upper shunt capacitor leads to the reduction of ac components of the input current, which reduces the reverse power flow and the power loss occurring in the internal resistance of the dc power source and line impedance. In this paper, a circuit model of class DE inverter with considering each equivalent series resistance (ESR) is given. Based on the circuit model, the circuit equations are built, and the state equations are drawn in each state. The power loss caused by the input current is numerically calculated from the state equations. The waveforms and power conversion efficiencies are confirmed in circuit experiments. The asymmetric shunt capacitors, especially minimizing the upper shunt capacitor, offer the highest power conversion efficiency