Reactive Power Elimination for High Conversion-Ratio Bidirectional Resonant Converter

This article presents a reactive power elimination method for high conversion-ratio bidirectional resonant converter with ripple-free current at the low voltage side. When transferring power in the backward mode operation, the converter with heavy loads suffers from significant reverse current that generates reactive power. By adjusting the right amount of phase of the pulsewidth modulation signals, we can eliminate the reverse current and the corresponding reactive power. We derive the voltage gain, calculate the right amount of phase, and identify the load threshold, above which the reverse current appears. We use a 600 W converter prototype to demonstrate the performance of the proposed converter.