New auxiliary circuit for boost converter to achieve soft-switching operation and zero input current ripple

In this study, a simple auxiliary circuit is proposed and investigated to provide soft-switching operation in the boost converter. The proposed auxiliary circuit includes only a small auxiliary inductor and two auxiliary capacitors. In this structure, by implementing the auxiliary inductor, a negative current flows through the power switch before its turn-on moment. Therefore, the power switch turns on under zero voltage switching condition. In addition, by properly designing the parallel capacitor of the power switch, a soft-switching condition can be achieved for its turn-off. Furthermore, implementing this simple auxiliary circuit can be helpful to decrease the reverse recovery losses of the diode since the diode turns off under zero current switching condition. Another advantage of the proposed structure is its zero input current ripple. In this study, the performance of the proposed auxiliary circuit with conventional boost converter has been analysed, and designing the methodology of the auxiliary components is presented. Voltage stress and power loss of components, converter voltage gain, and closed-loop model of the converter have been investigated. Moreover, the performance of the proposed auxiliary circuit is compared with previous works and its operation is investigated in a 200 W laboratory prototype.