A Novel Filter Built-in Isolated Bi-directional DC-DC Converter with Split Windings

A novel filter built-in converter with split windings is presented. Because of its extreme simplicity, flexibility, and efficiency, it has the potential to replace some of the conventional electric power conversion methods used today. The background, design, and operation of the proposed filter built-in converter are discussed in this paper. The proposed converter is derived from a dual active half bridge (DAHB) converter, and it can achieve zero-ripple-current operation and LC low-pass filter function by the split windings and tank capacitors. Due to the zero-ripple-current operation and the LC low-pass filter function, the proposed converter can eliminate or decrease the input and output filters, and with a phase-shift control strategy, all the switches are operated under zero-voltage switching (ZVS) condition. In order to design a power flow control function and a filter function simultaneously, theoretical equations for these functions are derived. Finally, the DAHB and the proposed converter prototypes are constructed for comparison. The results show that the noise in the input port of the proposed prototype is smaller than that of the DAHB prototype by 16 dB (peak), and the proposed approach can achieve a significant improvement in efficiency.