Research on Topology Optimization of a Dual Bridge Wide Voltage Range LCLC Resonant Converter

In the traditional DC/DC structure, LLC resonant converter has been widely used in electric vehicles, new energy power generation, and other energy fields as a superior electric energy DC conversion topology due to its good soft switching characteristics, high energy transmission efficiency, and other advantages, but it is difficult for traditional DC/DC converters to take into account both high efficiency and wide voltage output range. Add a bidirectional switch in the pre-inverter circuit, can make the inverter circuit switch back and forth directly in the half-bridge and the full-bridge, broaden the voltage input range of the pre-stage, simultaneously connect an LC branch in parallel on the primary side of the transformer in the resonator, can make the equivalent excitation inductance of the converter change with frequency rate, and then expand the gain range and reduce the resonant current simultaneously, further weaken the influence of the excitation inductance, finally, replace a diode with an active switch in the rectifier network, can change the rectifier structure by controlling the conduction of this switch tube, which in turn expands the output voltage to twice that of the half-bridge mode. The topology is controlled by frequency conversion and phase shift to achieve the purpose of broadening the output voltage and improving the efficiency, and the principle is analyzed, and the simulation is carried out in the MATLAB/Simulink environment, and the superiority and feasibility of the optimized topology are verified by the simulation of the experimental waveform.