An Optimal Modulation for a Semi Dual-Bridge Resonant Converter with a SCC-based Tunable Tank

To enhance the efficiency of a semi dual-bridge resonant converter(SDBRC), a control strategy to minimize the root mean square(RMS) current and eliminate the backflow power is proposed. An optimal operating point is precisely selected to reduce the conduction loss due to backflow power and high rms current. The converter is enabled to work with the optimal operating point in the whole load range by adjusting the switch-controlled capacitor (SCC) based tunable resonant tank continuously. Soft-switching of all switches can be maintained along the control route as well. A lab prototype converter designed at 300 W is tested to validate the SCC-based topology and proposed modulation scheme. The experimental result has demonstrated that the proposed topology and modulation scheme can improve the converter efficiency over the whole load range, especially in the light load condition.