A Novel Virtual-Ground Coupled-Inductor High-Gain Single-Phase Single-Stage Buck–Boost Inverter With Low-Voltage Stress

Abstract

To solve the problems of nonisolated inverters applied to photovoltaic systems, fuel cells, and battery energy storage, such as low dc input voltage with wide fluctuations, and leakage current, this article presents a novel virtual-ground coupled-inductor high-gain single-phase single-stage buck–boost inverter (SSBBI) with low-voltage stress. The operation principle and modulation strategy are analyzed based on the proposed inverter, and the proposed inverter can achieve high-efficiency power conversion with high-voltage gain, low-leakage current, and low-voltage stress. In addition, the filter inductor is designed to be much smaller by magnetic coupling, improving the power density of the inverters. The gain characteristics considering parasitic parameters, detailed circuit parameter design, and loss calculation analysis are also presented. The leakage current elimination mechanism is analyzed based on the inverter circuit model and operating status. Finally, the theoretical analysis and performance of the proposed topology are experimentally validated using a 500 W inverter prototype.