Three-phase power converter; Grid synchronization; Phase locked loop(PLL); Enhanced second order generalized integrator(ESOGI)
Issue Date
2017-05
Publisher
KOREAN INST ELECTR ENG
Citation
JOURNAL OF ELECTRICAL ENGINEERING & TECHNOLOGY, v. 12, no. 3, page. 1101-1107
Abstract
In this paper, a robust and fast grid synchronization method of a three-phase power converter is proposed. The amplitude and phase information of grid voltages are essential for power converters to be properly connected into the utility. The phase-lock-loop in synchronous reference frame has been widely adopted for the three-phase converter system since it shows a satisfactory performance under balanced grid voltages. However, power converters often operate under abnormal grid conditions, i.e. unbalanced by grid faults and frequency variations, and thus a proper active and reactive power control cannot be guaranteed. The proposed method adopts a second order generalized integrator in synchronous reference frame to detect positive sequence components under unbalanced grid voltages. The proposed method has a fast and robust performance due to its higher gain and frequency adaptive capability. Simulation and experimental results show the verification of the proposed synchronization algorithm and the effectiveness to detect positive sequence voltage.