Current-fed two-inductor bi-directional DC/DC converter with wide output voltage range

Abstract

The current-fed two-inductor boost converter (CF-TIBC) has previously been demonstrated to have advantages in operating low voltage and high current input applications. Such characteristics are suited for photovoltaic (PV) or battery application, likes energy storage system (ESS) or electric vehicle (EV). In this paper, the current-fed two-inductor bi-directional DC/DC converter (CF-TIBDC) is proposed. The proposed converter overcomes drawbacks of the conventional CF-TIBC, which are only one way power flow and voltage spike when the switches are turned off. By using the resonant components, the voltage spike problem is solved, and all switches in the CF-TIBDC meet the zero voltage switching (ZVS) condition. Likewise, the zero current switching (ZCS) condition is achieved through the switches on the low voltage stage. A wide range of output voltages with soft-switching is achieved by frequency-duty control. As a result, the proposed converter can maintain high efficiency across the entire range. The principles of the operation characteristics are presented with theoretical analysis, and the proposed converter is verified through PSIM simulation and experiment with a 300W laboratory prototype.