A high step-up DC-DC converter with intermediate capacitor and coupled inductors

In this paper a high step-up interleaved boost converter is proposed for renewable energy applications. The proposed converter uses multi-phase/interleaving technique with two coupled inductors in one phase and an intermediate capacitor between the two phases. The idea is such that the coupled inductors are used to develop a high voltage across the intermediate capacitor and then this high voltage is transferred to the output to achieve a high step-up voltage gain with appropriate duty cycle. The operating principle and steady state analysis of the converter are discussed in detail which shows several advantages over a traditional interleaved boost converter. These advantages include a very high voltage conversion ratio and reduction in the voltage stress of the transistor switches. A simulation has been carried out for proposed converter as well as conventional interleaved boost converter (IBC) to verify the performance of the proposed converter. Finally a 32-W, 20-V input, 160-V output laboratory prototype is built and tested to verify simulation results and effectiveness of the proposed converter.