Impedance Control Network Resonant dc-dc Converter for Wide-Range High-Efficiency Operation

Abstract

This paper introduces a new resonant converter architecture that utilizes multiple inverters and a lossless impedance control network (ICN) to maintain zero-voltage switching and near zero-current switching across wide operating ranges. Hence, the ICN converter is able to operate at fixed frequency and maintain high efficiency across wide ranges in input and output voltages and output power. The ICN converter architecture enables increase in switching frequency (hence reducing size and mass), while achieving very high efficiency. Three prototype 200-W 500-kHz ICN resonant converters, one with low-Q, one with medium-Q, and one with high-Q resonant tanks, designed to operate over an input voltage range of 25 to 40 V and an output voltage range of 250 to 400 V are built and tested. The low-Q prototype ICN converter achieves a peak efficiency of 97.1%, maintains greater than 96.4% full power efficiency at 250 V output voltage across the nearly 2:1 input voltage range, and maintains full power efficiency above 95% across its full input and output voltage range. It also maintains efficiency above 94.6% over a 10:1 output power range across its full input and output voltage range owing to the use of burst-mode control.