Analysis, design and implementation of a high step-up multi-port non-isolated converter with coupled inductor and soft switching for photovoltaic applications

Abstract

In this paper, a new structure of a non-isolated multi-input converter is presented that is capable of generating high voltages to increase the efficiency of the converter, which uses a combination of a coupled inductor and a voltage multiplier cell. By combining these two methods, it is possible to use switches with low voltage stress and therefore low conductivity. This type of structure is suitable for photovoltaic (PV) applications. The proposed converter has two distinct phases for each input, which can be used to properly control the energy received from each source using two separate phases. The performance of the proposed converter depends on the charging or discharging mode of the energy storage system (ESS). To design a high step-up non-isolated multi-input converter, first the structure and performance of the proposed converter are thoroughly investigated. The exact design method is presented for the correct operation of the converter and the simulation results for different modes of the converter operation are shown. Finally, in order to confirm the accuracy of the simulation results of the proposed converter, a laboratory sample of the proposed converter to supply a 400 W–400 V load is implemented and a comparison between the theoretical and practical results is performed.