A Family of Zero-Current-Transition Transformerless Photovoltaic Grid-Connected Inverter

作者：Xiao, Hua F.^*; Lan, Ke; Zhou, Bin; Zhang, Li; Wu, Zaijun

来源：IEEE Transactions on Power Electronics, 2015, 30(6): 3156-3165.

DOI：10.1109/TPEL.2014.2337513

• Grid-connected inverter
• resonant tank
• transformerless
• zero-current-transition (ZCT)

Low leakage current and high efficiency are two key indexes for transformerless PV grid-connected inverter. The transformerless inverter topologies have superior efficiency thanks to saving transformer, but their semiconductor devices are still on hard-switching state at present. First and foremost, a novel zero-current-transition (ZCT) concept for the single-phase full-bridge transformerless PV grid-connected inverters is presented in this paper. Second, the zero-current turn-off for high-frequency main switches of the inverters and the zero-current turn-on for auxiliary switches added are achieved by introducing two resonant tanks. Furthermore, a family of ZCT transformerless grid-connected inverters with sinusoidal pulse width modulation is deduced. Especially, taking zero-current-transition six-switch full-bridge topology (ZCT-H6-I) as an example, its operation principle, soft-switching conditions, duty cycle constraints, and parameter design procedure of the resonant tank are analyzed in detail. Finally, the validity of the ZCT concept is verified by a ZCT-H6-I prototype rated at 50 kHz, 1 kW.

• 出版日期2015-6
• 单位东南大学