Comparative study between three-leg and four-leg current-source inverter for solar PV application

Generation of electricity from the non-conventional energy sources requires efficient equipment to transfer energy to the grid. Highly efficient and good operating life of photovoltaic inverters and transformers are required. Normally voltage source inverters are used for solar PV application. But current source inverters are more reliable than the voltage source inverters. This paper discusses the implementation of a three-leg current source based inverter using three-phase space vector pulse width modulation. This will inject high earth leakage current to the grid and also results in high common mode voltage. To minimize the leakage current an isolation transformer can be used. Due to the addition of this equipment, size and cost increases, and the total efficiency decreases. To overcome this limitation Four-leg current source inverter is proposed. In this proposed method, we can suppress the common mode voltage and the earth leakage current. In this paper provides comparative results of 3-leg and 4-leg current source inverters.