LLC resonant partial power step-up DC-DC converter

An LLC resonant partial power converter (LLC-RPPC) for direct current step-up applications is presented. In the proposed LLC-RPPC, a major part of electrical power flows to the load at approximately 100% efficiency and only a part of electrical power is processed through LLC resonant converter. Accordingly, the proposed LLC-RPPC can be designed to attain an overall efficiency of above 90% under all operating conditions. The converter has several advantages over conventional counterparts such as lower switching losses, less EMI loss, and higher efficiency. The structure, operation, and analysis of the proposed LLC-RPPC is described in this paper. The operation and performance of the proposed LLC-RPPC is evaluated through experimental results. For this purpose, a laboratory prototype of the proposed LLC-RPPC rated at 85W was designed, built, and tested. The results obtained from experimentation are given in the paper. The results reveal excellent ZVS and ZCS switching performance of switches and diodes on the primary and secondary sides respectively over the entire range of operations.