Non-isolated high step-up DC-DC converter based on coupled inductor with reduced voltage stress

In this study, a novel topology for high step-up DC-DC converters is proposed based on coupled inductors. The proposed converter has many features, such as high conversion ratio, recycling the leakage energy of the coupled inductor, minimisation of voltage stress of components, simplicity of control and high efficiency. An optimisation process is employed to optimise coupled inductor turn ratios which minimise voltage stresses of the diodes and the switch. Minimisation of the switch voltage stress results in the use of switch with smaller on-resistance and improvement in the overall efficiency. The operation principles and steady-state analysis of continuous, discontinuous and boundary conduction modes are discussed in detail. The performance of the proposed converter is compared with the similar converters and it is concluded that new topology has considerable advantages over them. The simulation results verify the performance of the proposed circuit. A 250 W prototype with 400 V output voltage is implemented and the experimental results are in a good agreement with the simulation results.