A 97% Peak Efficiency 12V to 1V 500A Multi-Phase Direct Power Converter for High Current Applications

This paper presents a 12-1V fixed gain Multi-Phase Direct Power Converter, a one-stage converter for high current applications. Based on the Direct Power Converter and it's operation principles, it enables duty cycles up to 85 to 90% for all the power switches, reducing drastically the rms current in the power devices, zero voltage switching (ZVS) in both primary and secondary side and zero current switching (ZCS) in secondary side. Due to the expected high output current, Segmented Winding Transformer (SWT) was also implemented to reduce secondary side losses. A prototype with four phases parallel connected is designed and build to split the high output current into multiple parallel current paths, allowing to reduce the output voltage ripple and the overall capacitance as the phases can be shifted. The prototype was tested up to 550A, achieving a peak efficiency of 97% at 200A and 95% efficiency at full load (500A) with a switching frequency of 150kHz, which allows to parallelize power switches without increasing driving losses dramatically.