Aimed at the problem of wide frequency range and large circulating current with the traditional frequency-controlled LLC resonant converter in wide output voltage applications,a fixed-frequency PWM controlled hybrid bridge dual-LLC resonant converter is studied. According to the difference in the primary-side structure,the converter has three forms of topology,i.e.,half-bridge-half-bridge,half-bridge-full-bridge and full-bridge-full-bridge,in which the primary-side structure is in parallel and the two transformers on the secondary-side are in series. Compared with the traditional frequency-controlled LLC converter,the three topologies always work at the resonant frequency,which reduces the switching frequency range. In addition,under the PWM control strategy,the three topologies can achieve 2,3 and 4 times voltage gain,respectively,thereby adapting to wide voltage scenarios. At the same time,the circuit has a low circulating current loss and a good soft switching performance. Simulink simulation and experimental results verified the feasibility of the proposed scheme.
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