A Rejection of Harmonic Ripples for d-q Transformation

d-q 변환에서의 고조파 맥동 제거

Choi, Nam-Yerl;Lee, Chi-Hwan

  • Received : 2015.09.21
  • Accepted : 2015.10.23
  • Published : 2015.12.31


This paper presents a simple notch filter, which is so suitable for three-phase unbalanced and distorted power line. In the d-q synchronous transformation, three-phase unbalanced and distorted voltages generate lots of ripple voltages on d-q axes. The ripples make disturbances on controllers such as PLL of phase tracking. Unbalanced state makes ripple of double the frequency of power line. Odd harmonics 5th and 7th on the line make even 4th and 6th ripples on d-q axes due to the rotating reference frame, respectively. Cascaded two comb filters, delay lines 1/4T and 1/8T, are adopted for the ripple rejection. The filter rejects harmonics 2nd, 4th, 6th, 10th and so on. They are very effective to remove the ripples of both unbalance and distortion. The filter, implemented by two FIFOs on an experimental system, is adopted on a PLL controller of power line phase tracking. Through the simulation and experimental results, performance of the proposed comb filter has been validated.


DQ Transformation;Unbalanced Grid Voltage;Synchronous Reference Frame;Comb Filter


  1. Se Kyo Chung, "A phase tracking system for three phase utility interface inverters", IEEE Trans. PE, vol. 15, no. 3, pp.431-438, May 2000.
  2. T. Timbus, M. Liserres, R. Teodorescu, and F. Blaabjerg, "Synchronization Methods for Three Phase Distributed Power Generation System, An Overview and Evaluation", Conf. Rec. of IEEE-PESC, pp.2474-2481, 2005.
  3. Pedro Rodriguez, Josep Pou, "Decoupled Double Synchronous Reference Frame PLL for Power Converters Control", IEEE Trans. PE, vol. 22, no. 2, pp.584-592, 2007.
  4. Marcelo A. Perez, "A Robust Phase-Locked Loop Algorithm to Synchronize Static-Power Converters With Polluted AC Systems", IEEE Trans. IE, vol. 55, no. 5, pp.2185-2192, 2008.
  5. Felice Liccardo, Pompeo Marino, and Giuliano Raimondo, "Robust and Fast Three-Phase PLL Tracking System", IEEE Trans. IA., vol. 58, no. 1, pp.221-231, 2011.
  6. Y. F. Wang and Y. W. Li, "Grid synchronization PLL based on cascaded delayed signal cancellation," IEEE Trans. PE., vol. 26, no. 7, pp. 1987-1997, Jul. 2011.
  7. S. Golestan, M. Ramezani, J. Guerrero and M. Monfared, "dq-frame cascaded delayed signal cancellation-based PLL: analysis, design, and comparison with moving average filter-based PLL", IEEE Trans. PE., vol. 30, no. 3, pp. 1678-1632, March 2014.