A transformerless photovoltaic grid-connected system of three-phase single-stage boost inverter with coupled inductor

This paper presents a modified coupled-inductor single-stage boost inverter based grid-connected PV system with proper modulation technique to reduce leakage current. Only a diode is added in the front of the topology compare to the original structure, to block the leakage current loop when in the active states and traditional zero states. On the other hand, the modified near-state PWM (NSPWM) technique is applied with shoot-through zero state in order to reduce the leakage current through the conduction path when shoot-through zero state transform to active state and vice verse. Simulation results for the transformerless photovoltaic system are presented in two cases: CL-SSBI with maximum constant boost (MCB) control and CL-SSBI-D with NSPWM control. Experimental results of transformerless photovoltaic system are also obtained to verify the accuracy of theoretical and simulation models. ©, 2015, Diangong Jishu Xuebao/Transactions of China Electrotechnical Society. All right reserved.