A New Coupled-Inductor-Free Bidirectional DC-DC Converter with Low Current Ripple in Both Sides

The proposed bidirectional converter exhibits a superior voltage gain compared to conventional designs and maintains low current ripple on both sides, making it highly suitable for photovoltaic and fuel cell applications. Notable features include the use of compact output filter capacitors, adequate voltage gain in both operational modes, and the elimination of coupled inductors. In step-up operation, switches S ₁ and S ₂ are activated simultaneously, while in step-down operation, switches S ₃ , S ₄ , and S ₅ are triggered at the same time. This switching scheme enables the converter to operate in each mode with a single PWM control signal, thereby simplifying the control circuitry. A thorough analysis has been carried out for both operating modes, and experimental verification using a 400 W prototype has confirmed a peak efficiency of 96.3%, validating the theoretical predictions.