标题：Dual Half-Cycle-Bridges Single-Phase Photovoltaic Inverter
作者：Zhou, Liwei ;Gao, Feng ;Xu, Tao ;Duan, Wen
作者机构：[Zhou, Liwei ;Gao, Feng ;Xu, Tao ;Duan, Wen ] School of Electrical Engineering, Shandong University, Jinan, China
会议名称：7th Annual IEEE Energy Conversion Congress and Exposition, ECCE 2015
会议日期：20 September 2015 through 24 September 2015
来源：2015 IEEE Energy Conversion Congress and Exposition, ECCE 2015
关键词：common mode voltage; grid connected inverter; unipolar switching strategy
摘要：In a transformer-less photovoltaic (PV) grid-connected system, there exists a galvanic connection between the grid and the PV array. Without any transformer in the inverter, common-mode leakage currents can flow through the stray capacitance between the PV array and the ground. This paper first analyzes the equivalent common-mode circuit of single-phase inverter, and compares several single-phase inverters with constant common-mode voltage. This paper then proposes a novel dual half-cycle-bridges (DHCB) single-phase PV inverter with low conduction losses. A novel hybrid SPWM modulation method is introduced to achieve the minimum switching losses under any power factor operation. Next, adding a neutral point clamped circuit to the DHCB inverter, the common-mode voltage can be clamped to half of DC voltage firmly. Finally, simulation and experimental results have validated the theoretical findings. © 2015 IEEE.