A fully protected push-pull current-fed dc-dc converter

This paper presents an isolated dc-dc converter designed to operate as a primary stage of an on-board dc-ac power supply for diesel-electric engines. The dc-ac power supply must provide a sinusoidal waveform of 127V rms from 72V dc bus of the engine. The dc-dc push-pull current-fed converter has been used to obtain an isolated 200V de output voltage from the available 72V de bus engine. This converter operates as a boost converter with constant frequency and duty cycle greater than 50%. Two control loops operating in cascade mode were used. A fast inner current loop regulates the boost inductor current, Whereas an external control loop keeps a constant output voltage. The experimental results have been obtained for a 300W laboratory prototype operating at 50kHz. The converter efficiency was 93% at full load, and the output voltage regulation was less than 1% for 10% to 100% load changes.