Time delay compensation for a current-source active power filter using state-feedback controller

The inevitable time delay in a digital signal processing (DSP) based controller can significantly degrade the performance of an active power filter. With a current-source active power filter (CS-APF) the problem can be more severe as this time delay can excite the filter resonance and cause oscillations in the compensation current. The paper derives the state space model for the CS-APF where the time delay is modeled properly into the state equations of the system. This makes the system dynamic model more accurate and the time delay can be compensated when a controller is designed for the system. State space control strategy is selected for the CS-APF controller. Experimental results from our prototype CS-APF system are presented to show the effect of the time delay on the CS-APF response and the validity of the proposed approach.

[1]  Mehrdad Kazerani,et al.  Modeling, control and implementation of three-phase PWM converters , 2003 .

[2]  J. D. van Wyk,et al.  Effectivity reduction of PWM-converter based dynamic filter by signal processing delay , 1999, PESC 1999.

[3]  Katsuhiko Ogata,et al.  Discrete-time control systems , 1987 .

[4]  D. G. Holmes,et al.  A generalised approach to the modulation of current source inverters , 1998, PESC 98 Record. 29th Annual IEEE Power Electronics Specialists Conference (Cat. No.98CH36196).

[5]  Mika Salo,et al.  A novel open-loop control method for a current-source active power filter , 2003, IEEE Trans. Ind. Electron..

[6]  G. Joos,et al.  Selective harmonic elimination and current/voltage control in current/voltage source topologies: a unified approach , 1999, IECON'99. Conference Proceedings. 25th Annual Conference of the IEEE Industrial Electronics Society (Cat. No.99CH37029).

[7]  O. Ojo,et al.  Carrier-based discontinuous PWM modulation for current source converters , 2004, Conference Record of the 2004 IEEE Industry Applications Conference, 2004. 39th IAS Annual Meeting..

[8]  William S. Levine,et al.  The Control Handbook , 2005 .

[9]  M. Kazerani,et al.  Comparative evaluation of three-phase PWM voltage- and current-source converter topologies in FACTS applications , 2002, IEEE Power Engineering Society Summer Meeting,.