High gain high power non-isolated DC-DC converter for renewable energy applications

In this paper, a non-isolated high step-up high power DC-DC converter based on coupled inductor and voltage multiplier cell (VMC) is proposed for renewable energy applications. To obtain high voltage gain and high output power, three interleaved coupled inductors and three VMCs are used. Each VMC consists of secondary winding of the coupled inductor, two diodes and two capacitors which charge and discharge alternately through the diodes. The three stages present in interleaved boost converter reduce the current stress on the switch and input current ripple. Voltage stress on the power switches is reduced by using coupled inductors with proper turns ratio. The proposed converter produces a voltage gain of 23 and delivers 3kW power output. The converter has a modular structure which facilitates smooth increment in voltage gain and output power requirement. The operating principle, characteristic waveforms, design details and simulation results of the proposed converter prove the desirable features.