Improvement of an input waveform of a Neutral Point Type Step-down Converter

This paper presents one of the methods to improve a input current waveform of a neutral point type step-down converter circuit which we developed before. A neutral point type step-down converter circuit shares switching devices with half bridge inverter, and it is the circuit which can constitute an electronic ballast of a one converter method. A neutral point type step-down converter circuit has the problem that an input current does not flow through in the vicinity of zero cross point because It has some characteristic as step-down chopper circuit. This time, we solved this problem by adding an inductor to a circuit.