Boost inverter topology with high-frequency link transformer for PV grid-tied applications

Abstract

This paper proposes a new topology for single-phase photovoltaic PV grid-tied applications. The whole system consists of a two-stage, high-frequency boost inverter cascaded by rectifier–inverter system. A single-phase high-frequency transformer is used to link both stages and provide galvanic isolation between the AC and DC sides. A single-stage high-frequency boost inverter (HFBI), in the first stage, boosts and converts the DC output voltage of the PV array to a high-frequency single-phase square waveform and achieves maximum power point tracking (MPPT). In the second stage, the rectifier-inverter system (RIS) interfaces HFBI to the grid. The proposed topology has many advantages such as increasing the inverter output voltage level, MPPT, high reliability, small size, and light weight. In addition, a proportional integral current control (PI) is used to inject a sinusoidal current into the grid at unity power factor. The proposed topology has been verified analytically using PSIM software and experimentally by using a laboratory prototype.