A Fast and Robust Grid Synchronization Algorithm of a Three-phase Converters under Unbalanced and Distorted Utility Voltages

다국어 초록 (Multilingual 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.

참고문헌 (Reference)

1 A. Timbus, "Synchronization methods for three phase distributed power generation systems. an overview and evaluation" 2474-2481, 2005

2 X. Yuan, "Stationary-frame generalized integrators for current control of active power filters with zero steadystate error for current harmonics of concern under unbalanced and distorted operating conditions" 38 (38): 523-532, 2002

3 L. Arruda, "PLL structures for utility connected systems" 4 : 2655-2660, 2001

4 F. Blaabjerg, "Overview of Control and Grid Synchronization for Distributed Power Generation Systems" 53 (53): 1398-1409, 2006

5 V. Kaura, "Operation of a phase locked loop system under distorted utility conditions" 2 : 703-708, 1996

6 P. Rodriguez, "New positive sequence voltage detector for grid synchronization of power converters under faulty grid conditions" 1492-1498, 2006

7 P. Rodriguez, "Double synchronous reference frame PLL for power converters control" 1415-1421, 2005

8 Rodriguez, P., "Decoupled Double Synchronous Reference Frame PLL for Power Converters Control" 22 (22): 584-592, 2007

9 R. M. Santos Filho, "Comparison of Three Single-Phase PLL Algorithms for UPS Applications" 55 (55): 2923-2932, 2008

10 L. Zhang, "Characteristic of voltage dips(sags)in power systems" 15 (15): 827-832, 2000

11 S. -K. Chung, "A phase tracking system for three phase utility interface inverters" 15 (15): 431-438, 2000

12 S. Lee, "A new phase detection method for power conversion systems considering distorted conditions in power system" 4 : 2167-2172, 1999

13 M. Karimi-Ghartemani, "A method for synchronization of power electronic converters in polluted and variable-frequency environments" 19 (19): 1263-1270, 2004