Frequency Characteristics of the Synchronous-Frame Based D-Q Methods for Active Power Filters

  • Wang, Xiaoyu (School of Electrical Engineering, Xi'an Jiaotong University) ;
  • Liu, Jinjun (School of Electrical Engineering, Xi'an Jiaotong University) ;
  • Hu, Jinku (School of Electrical Engineering, Xi'an Jiaotong University) ;
  • Meng, Yuji (School of Electrical Engineering, Xi'an Jiaotong University) ;
  • Yuan, Chang (School of Electrical Engineering, Xi'an Jiaotong University)
  • Published : 2008.02.20

Abstract

The d-q harmonic detecting algorithms are dominant methods to generate current references for active power filters (APF). They are often implemented in the synchronous frame and time domain. This paper researches the frequency characteristics of d-q synchronous transformations, which are closely related to the analysis and design issues of control system. Intuitively, the synchronous transformation is explained with amplitude modulation (AM) in this paper. Then, the synchronous filter is proven to be a time-invariant and linear system, and its transfer function matrix is derived in the stationary frames. These frequency-domain models imply that the synchronous transformation has an equivalent effect of frequency transformation. It is because of this feature, the d-q method achieves band-pass characteristics with the low pass filters in the synchronous frame at run time. To simplify these analytical models, an instantaneous positive-negative sequence frame is proposed as expansion of traditional symmetrical components theory. Furthermore, the synchronous filter is compared with the traditional bind-pass filters based on these frequency-domain analytical models. The d-q harmonic detection methods are also improved to eliminate the inherent coupling effect of synchronous transformation. Typical examples are given to verify previous analysis and comparison. Simulation and experimental results are also provided for verification.

References

  1. B. Singh, K. Al-Haddad, and A. Chandra, 'A review of active filters for power quality improvement,' Industrial Electronics, IEEE Transactions on, vol. 46, no. 5, pp. 960-971, 1999 https://doi.org/10.1109/41.793345
  2. Ortega, J.M.M. Esteve, M.P. Payan, M.B. Exposito, A.G. Franquelo, L.G. , 'Reference current computation methods for active power filters: accuracy assessment in the frequency domain,' Power Electronics, IEEE Transactions on, vol. 20, no. 2, pp. 446-456, 2005 https://doi.org/10.1109/TPEL.2004.842970
  3. C. Donghua and X. Shaojun, 'Review of the control strategies applied to active power filters,' in Electric Utility Deregulation, Restructuring and Power Technologies, 2004.(DRPT 2004).Proceedings of the 2004 IEEE International Conference on, 2 ed 2004, pp. 666-670
  4. H. Akagi, et. al, 'Instantaneous Reactive Power Compensators Comprising Switching Devices without Engergy Storage Components,' IEEE Trans on IA, vol. 20, no.3, pp. 625-630, 1984
  5. H. Akagi, et al, 'Control Strategy of Active Power Filters Using multiple Voltage-Source PWM converters,' IEEE Trans. on IA, vol.22, no.3, pp.460-465, 1986
  6. V. Soares, P. Verdelho, and G. Marques, 'A control method for active power filters under unbalanced nonsinusoidal conditions,' in Power Electronics and Variable Speed Drives, 1996.Sixth International Conference on (Conf.Publ.No.429) 1996, pp. 120-124
  7. V. Soares, P. Verdelho, and G.D. Marques, 'An instantaneous active and reactive current component method for active filters,' Power Electronics, IEEE Transactions on, vol. 15, no. 4, pp. 660-669, 2000 https://doi.org/10.1109/63.849036
  8. J.S. Tepper, J.W. Dixon, G. Venegas, and L. Moran, 'A simple frequency-independent method for calculating the reactive and harmonic current in a nonlinear load,' Industrial Electronics, IEEE Transactions on, vol. 43, no. 6, pp. 647-654, 1996 https://doi.org/10.1109/41.544552
  9. F.Z. Peng, H. Akagi, and A. Nabae, 'Compensation characteristics of the combined system of shunt passive and series active filters,' Industry Applications, IEEE Transactions on, vol. 29, no. 1, pp. 144-152, 1993 https://doi.org/10.1109/28.195900
  10. Zmood, D.N. Holmes, D.G. Bode, G.H., 'Frequency-domain analysis of three-phase linear current regulators,' Industry Applications, IEEE Transactions on, vol. 37, no. 2, pp. 601-610, 2001 https://doi.org/10.1109/28.913727
  11. Newman, M.J. Zmood, D.N. Holmes, D.G. , 'Stationary frame harmonic reference generation for active filter systems,' Industry Applications, IEEE Transactions on, vol. 38, no. 6, pp. 1591-1599, 2002 https://doi.org/10.1109/TIA.2002.804739
  12. R. Pedro, P. Josep, B. Joan, J. I. Candela, P. B. Rolando, and B. Dushan, 'Decoupled Double Synchronous Reference Frame PLL for Power Converters Control,' Power Electronics, IEEE Transactions on, vol. 22, no. 2, pp. 584-592, 2007