Improved Single PWM Control of Active-Bridge Converters for High Efficiency and Wide ZVS Operation

Abstract

A novel control methodology for multiactive-bridge (MAB) converters, termed the single PWM (SPWM) technique, aimed at reducing both conduction and switching losses, is proposed in this article. The proposed control algorithm achieves soft switching across all load conditions while optimizing the converter’s overall conduction loss by minimizing the RMS currents of the three ports for the MAB converters, particularly under light-load conditions. By employing only two control variables—primary and secondary phase shifts (φ_d) and zero-voltage turn-on intervals (α or β)—the control complexity is significantly reduced compared to conventional MAB control algorithms, which rely on multiple variables and incur high computational overhead. The SPWM control method thus enables efficient and straightforward converter operation under both step-up and step-down conditions. Simulation and experimental results at a 10 kHz operating frequency and 70 kW power delivery demonstrate that the proposed method consistently achieves soft switching and minimizes the RMS currents of all three ports under various voltage and power conditions, leading to efficiency improvements of up to 0.6% compared to conventional SPWM techniques.