A Hybrid Interleaved DC-DC Converter Based on Buck-Boost topologies for Medium Voltage Applications

Abstract

DC-DC power converters with high voltage gain are primary components for renewable energy generation such as offshore wind farms. As the DC-DC converters installed in these farms should have limited size and weight, the non-isolated DC-DC converters are the most suitable choose for the offshore wind farms. Although, several DC-DC converters with high voltage gain have been developed for offshore wind farms. Most of them includes large count of semiconductors or experiences high voltage stresses. In this paper, a reduced components count converter is proposed for the collector system of offshore wind farms. The proposed topology is a modular input parallel output series non-isolated DC-DC converter. It is a hybrid interleaved structure which combines two buck-boost topologies into a single converter. The proposed converter aims to offer high voltage gain with reduced voltage and current stress on the converter's components. Moreover, the interleaved PWM offers limited output voltage ripple and supply current ripple. The operation modes and the steady-state performance of the proposed converter are analysed. In addition, a small signal model based on the state space averaged method is developed for the proposed converter. The accuracy of the developed model is verified using the converter's switching model. Furthermore, the output voltage control scheme utilizing a simple PI controller for the proposed converter is presented.