A Dual LC Interleaved Four-Port Converter for Bipolar DC Microgrids

In order to maintain the voltage balanced of the long bipolar low-voltage dc supply and utilization system, multiple distributed voltage balancers (VBs) are demanded. A four-port converter with dual LC balancing branches is proposed in this article to reduce the hardware cost of a distributed VB. The converter consists of two dual active bridges (DABs) and two LC balancing branches. The LC branches and DAB full-bridge circuits on the grid side form two interleaved LC VBs. The proposed converter integrates voltage balancing and device grid connection functions through a switch-sharing technology, which can effectively replace distributed VB. Most importantly, both functions of the converter can be operated simultaneously. In addition, interleaved LC VB can achieve smaller grid-connected voltage ripple. All the switches of the converter turn <sc>on</sc> with zero-voltage switching. The validity of the proposed converter is verified through ± 375 V Simulink simulation and ± 24 V down-scaled power experimental prototype.