Abstract：The input-parallel output-parallel (IPOP) DC-DC converters are very suitable for low voltage and high current applications.For the IPOP converter,the way to ensure input-current sharing (ICS) and output-current sharing (OCS) among the constituent modules is difficult.All the existing methods are closed-loop control schemes.In this paper,the IPOP LLC resonant converter modules are developed based on current balancing cells.Through the magnetic-coupling effect of the current balancing cell,the LLC resonant converter modules can achieve ICS and OCS that guarantee that the IPOP system work stably.The LLC resonant converter can be used as a high-frequency isolation DC transformer under the quasi-resonant mode,which can achieve zero voltage switching (ZVS) for the inverter side and zero current switching (ZCS) for the rectifier side so as to ensure high power density and high efficiency.By employing the current balancing cell instead of the traditional control schemes to solve the unequal current-sharing problem of IPOP system,the sampling and control circuit can be saved,which ensures high reliability and low cost.From analyzing the electromagnetic mode of the current balancing cell,its electrical circuit model can be built.And the simulations of the current balancing cell’s steady-state and dynamic-state current-sharing performances demonstrate the working principle.Finally,an IPOP LLC resonant converter module hardware prototype based on the current balancing cell is designed and built up to verify the validity and performance of the proposed solution.
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2016, Vol. 31 
