A fixed-frequency LCC-type resonant converter with inductive output filter using a modified gating scheme

A fixed frequency, series-parallel or LCC-type resonant converter with an inductive output filter, controlled using a modified gating scheme is proposed. The converter is analyzed for steady-state using approximate complex ac circuit analysis method. Based on the analysis, a simple design procedure is given and illustrated with a design example of a 300 to 420 V DC input; 1 kW, 48 V output converter. This converter using a modified gating scheme has increased number of switches operating with zero-voltage switching. Detailed PSIM simulation results are presented to demonstrate the performance of the designed converter for wide variations in the input voltage and load conditions. The designed converter requires a narrow variation in the pulse-width of the gating signals for wide variation in the load while the peak current through the switches decrease with the load current.