Interleaved High Step-Up Converter Integrating Coupled Inductor and Switched Capacitor for Distributed Generation Systems

A new interleaved high step-up dc-dc converter is proposed for distributed generation systems. By integrating coupled-inductor and switched-capacitor techniques, the proposed converter achieves a very high step-up voltage gain without an extreme duty cycle or a high turns ratio. Also, a very low switch voltage stress can be achieved; thus, low-voltage-rating mosfets with a small on-resistance can be used to lower the conduction loss. Moreover, thanks to the interleaved operation at the input side, the input current is shared and low current ripple is obtained. Furthermore, the zero-current-switching of the switches is realized, and the reverse recovery problem of the diodes is alleviated. In addition, the leakage energy can be recycled and an additional clamp circuit is not required. The operation principles and characteristics of the converter are discussed in detail. A prototype with 20-V input and 400-V output is developed to verify the theoretical analysis.