High Efficiency Resonant DC/DC Converter Utilizing a Resistance Compression Network

This paper presents a new topology for a high-efficiency dc/dc resonant power converter that utilizes a resistance compression network (RCN) to provide simultaneous zero-voltage switching and near-zero-current switching across a wide range of input voltage, output voltage, and power levels. The RCN maintains desired current waveforms over a wide range of voltage operating conditions. The use of ON/OFF control in conjunction with narrowband frequency control enables high efficiency to be maintained across a wide range of power levels. The converter implementation provides galvanic isolation and enables large (greater than 1:10) voltage conversion ratios, making the system suitable for large step-up conversion in applications such as distributed photovoltaic converters. Experimental results from a 200-W prototype operating at 500 kHz show that over 95% efficiency is maintained across an input voltage range of 25-40 V with an output voltage of 400 V. It is also shown that the converter operates very efficiently over a wide output voltage range of 250-400 V, and a wide output power range of 20-200 W. These experimental results demonstrate the effectiveness of the proposed design.