High efficiency voltage-clamped coupled-inductor boost converter

In this paper, a low voltage stress and high efficiency voltage-clamped coupled-inductor boost converter is proposed. The conventional coupled-inductor boost converter has a serious drawback of high voltage stresses across all power semiconductors due to the high surge voltage caused by the resonance between leakage inductor of coupled-inductor and stray capacitors. Therefore, the conventional converter must be equipped with the dissipative snubber for absorbing this surge voltage, which will degrade the overall power conversion efficiency. To overcome these drawbacks, the proposed converter employs the diode-clamping circuit instead of the dissipative snubber. Proposed clamping circuit can clamp voltages across the power switch and output diode on the link capacitor voltage and output voltage, respectively. In addition, the leakage inductor energy is stored in the link capacitor, and then transferred to the output side together with the input energy. Therefore, the proposed converter can achieve the higher efficiency than the conventional coupled-inductor boost converter. The proposed converter is expected to be well suited to various applications demanding the high efficiency and high-voltage gain. To confirm the validity of the proposed circuit, the theoretical analysis and experimental results of the proposed converter are presented.