title: Suppression of zero-crossing distortion for single-phase grid-connected photovoltaic inverters with unipolar modulation.
abstract: For single-phase grid-connected photovoltaic inverters, current-control with unipolar modulation can reduce the losses of power tubes and improve the efficiency compared with using the bipolar modulation. However, it suffers inherent zero-crossing distortion which is related to the grid current and voltage. In this paper, the reason for zero-crossing distortion is analyzed and simulated, also a novel current-control approach with commutating in advance is proposed to resolve this problem. This approach obtains a leading angle of the grid current by using the feedback of proportional-integral controller of the unipolar inverter, and then set the working mode of power tubes according to this angle through commutation.
authors.affiliation: School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zeng
authors.forename: Hong-bing
authors.initials: HB
authors.lastname: Xu
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.forename: Jian-guo
authors.initials: JG
authors.lastname: Chen