Harmonic Burst Control Strategy for Full-Bridge Series-Resonant Converter-Based EV Charging

An effective output voltage regulation method using harmonic burst control is presented. This method can greatly improve operating performance of the full-bridge series-resonant dc-dc converter (SRC) applied to electric vehicle (EV) battery charging. The proposed harmonic burst control not only provides load regulation, but it also achieves soft switching at both turn-ons and turn-offs under all load conditions. As a result, it improves the system efficiency over 10% for light-load conditions without any extra hardware, compared to that of the traditional frequency modulation method. Moreover, it has much smaller pulsed power over a wide range load compared to the traditional bang-bang burst control. Theoretical analysis of the series-resonant circuit and power loss analysis are discussed in detail in this paper. Experimental results based on a 1-kW prototype with 20-cm air gap between the primary and secondary sides of the series-resonant converter are presented to demonstrate the effectiveness of the proposed control strategy.