A Control Strategy Based on UTT and ISCT for 3P4W UPQC

This paper presents a novel control strategy of a threephase four-wire Unified Power Quality (UPQC) for an improvement in power quality. The UPQC is realized by integration of series and shunt active power filters (APFs) sharing a common dc bus capacitor. The shunt APF is realized using a thee-phase, four leg voltage source inverter (VSI) and the series APF is realized using a three-phase, three leg VSI. A control technique based on unit vector template technique (UTT) is used to get the reference signals for series APF, while instantaneous sequence component theory (ISCT) is used for the control of Shunt APF. The performance of the implemented control algorithm is evaluated in terms of power-factor correction, load balancing, neutral source current mitigation and mitigation of voltage and current harmonics, voltage sag and swell in a three-phase four-wire distribution system for different combination of linear and non-linear loads. In this proposed control scheme of UPQC, the current/voltage control is applied over the fundamental supply currents/voltages instead of fast changing APFs currents/voltages, there by reducing the computational delay and the required sensors. MATLAB/Simulink based simulations are obtained, which support the functionality of the UPQC. MATLAB/Simulink based simulations are obtained, which support the functionality of the UPQC.

Authors:

• Yash Pal
• A.Swarup
• Bhim Singh

Keywords:

• Power Quality
• UPQC
• Harmonics
• Load Balancing
• Power Factor Correction
• voltage harmonic mitigation
• currentharmonic mitigation
• voltage sag
• swell

References:

[1] E.W.Gunther and H.Mehta, A survey of distribution system power
quality, IEEE Trans. on Power Delivery, vol.10, No.1, pp.322-329,
Jan.1995.
[2] B. Singh, AL.K. Haddad and A. Chandra, A review of active filters for
power quality improvement, IEEE Trans. on Ind. Electron, vol.46, pp.
960-971, 1999.
[3] H Akagi, New trends in active Filters for power conditioning, IEEE
Trans. on Ind. Appl., 1996, 32, pp. 1312-1322.
[4] B.Singh,V. Verma,A. Chandra and K. Al-Haddad, Hybrid filters for
power quality improvement, Proc. IEE on Generation, Transmission and
Distribution, vol.152,pp.365-378,May2005.
[5] Arindam Ghosh, Gerard Ledwich, Power Quality Enhancement Using
Custom Power Devices,Kulwer International Series in Engineering and
Computer Science, 2002.
[6] N. G. Hingorani, Introducing custom power,Proc. IEEE Spectrum,
vol.32, pp.41-48, June1995.
[7] M. Aredes, K. Heumann, and E. H. Walandble, An universal active
power line conditioner, IEEE Trans. Power Del., vol. 13, no. 2, pp. 545-
551, Apr. 1998.
[8] H. Fujita and H. Akagi, The unified power quality conditioner: the
integration of series- and shunt-active filters, IEEE Trans. Power
Electron., vol. 13, no. 2, pp. 315-322, Mar. 1998.
[9] B. Han, B. Bae, H. Kim, and S. Baek, Combined operation of unified
power-quality conditioner with distributed generation, IEEE Trans.
Power Del., vol. 21, no. 1, pp. 330-338, Jan. 2006.
[10] Tan Zhili, Li Xun, Chen Jian, Kang Yong and Duan Shanxu, A direct
control strategy for UPQC in three-phase four-wire system, Proc. IEEE
Conf. on Power Electron. and Motion Control 2006,vol.2,pp.1-5.
[11] V.Khadkikar and A. Chandra, A Novel Structure for Three-Phase Four-
Wire Distribution System Utilizing Unified Power Quality Conditioner
(UPQC),IEEE Trans. Industry Applications,vol.45,pp.1897-1902,2009.
[12] Li.Xun,Zhu. Guorong ,Duan. Shanxu and Chen Jian Chen, Control
Scheme for Three-Phase Four-Wire UPQC in a Three-Phase Stationary
Frame, Procd.IEEE/IECON 2007, pp.1732-1736, 2007.
[13] A.Ghosh, A.K. Jindal and A. Joshi, A unified power quality conditioner
for voltage regulation of critical load bus, Proc. IEEE Power Eng.
Society General Meeting, June 2004, vol.1, pp471-476.
[14] B.Singh and Venkateswarlu, A Simplified Control Algorithm for Three-
Phase Four-Wire Unified Powe Quality Conditioner, Journal of Power
Electronics,vol.10, No.1,January2010.
[15] G.Chen, Y. Chen and K.M. Smedley, Three-phase four-leg active power
quality conditioner without references calculation, Procd. IEEE APEC
'04, vol.1, pp.587-593, 2004.