Performance Improvement of Active Power Filters based on P-Q and D-Q Control Methods under Non-Ideal Supply Voltage Conditions


In this paper, we investigate the effect of unbalanced and distorted supply voltages on the performance of active power filters that are based on the well-known p-q and d-q control methods. Our analysis shows that the harmonic suppression performance of the p-q and d-q control methods deteriorates when non-ideal sources are used. We propose the use of a self tuning filter (STF) with the p-q theory or d-q method as a way of alleviating the detrimental effects of non-ideal supply voltages. Simulation results show that the proposed method can improve the performance of active power filters under non-ideal voltage conditions.




 Fig.1.Block diagram of simulated APF



 Fig.2 Three phase balanced and undistorted (ideal) source voltage

Fig.3. Supply currents with p-q method under case 1. (THDi=2.1%)

Fig.4. Supply currents with d-q method under case 1. (THDi=2.07)

Fig.5. Distorted and unbalanced source voltages for case 2.


Fig.6. Supply currents with p-q method under case 2.

Fig.7. Supply currents with d-q method under case 2.

Fig.8. Supply currents with STF based p-q method under case 3.

Fig.9. Supply currents with STF based d-q method under case 3.


In this paper, we consider the effect of an unbalanced and distorted supply on the performance of the well-known p-q theory and d-q methods for active power filters. The ability of these methods to combat current harmonics deteriorates significantly when a non-ideal supply voltage is used. A modification to the p-q and d-q methods is then proposed for alleviating the effects of an imperfect supply. This involves the use of a self-tuning filter (STF) with p-q theory and the d-q method. We show that the total harmonic distortion of source current (THDi) can be reduced by up to around 2.30 % with the use of a STF under non-ideal voltage conditions. In addition, our comparative results show that an STFbased d-q method performs better than an STF-based p-q theory.


[1] W. Mack Grady, S. Santoso, “Understanding power system harmonics“, IEEE Power Eng. Rev. 21 (November (11)) (2001) 8-11.

[2] S. Biricik, O. C. Ozerdem “Investigation of Switched Capacitors Effect on Harmonic Distortion Levels and Performance Analysis with Active Power Filter“, Przeglad Elektrotechniczny, ISSN 0033-2097, R. 86 NR 11a/2010, pp 13-17.

[3] S. Buso, L. Malesani, P. Mattavelli, “Comparison of current control techniques for active filter applications,” Industrial Electronics, IEEE Transactions on , vol.45, no.5, pp.722-729, Oct 1998.

[4] H. Akagi, Y. Kanazawa, A. Nabae, “Generalized Theory of the Instantaneous Reactive Power in Three-Phase Circuits“, IPEC’83- Int. Power Electronics Conf., Tokyo, Japan, 1983, pp. 1375-1386.

[5] M. Asadi, A. Jalilian, H. F. Farahani, “Compensation of Unbalanced Non Linear Load and neutral currents using stationary Reference Frame in Shunt Active Filters,” Harmonics and Quality of Power (ICHQP), 2010 14th International Conference on, vol., no., pp.1-5, 26-29 Sept. 2010.

Leave a Reply

Your email address will not be published.