A New Topology of Three-Phase Four-Wire UPQC with a Simplified Control Algorithm
In this paper, a simplified control algorithm based on unit vector template generation (UVTG) is proposed for a star-delta supported three-phase four-wire (3P-4W) unified power quality conditioner (UPQC) topology for the improvement of different power quality problems. Different topologies reported in literature for 3P-4W UPQC use active compensation for the mitigation of source neutral current along with other power quality (PQ) problems, while the uses of passive elements for the mitigation of source neutral current are advantageous over the active compensation due to ruggedness and less complexity of control. Hence, in this paper a star-delta transformer is connected in shunt near the load for mitigation of source neutral current, while three-leg voltage source inverters (VSIs) based shunt and series active power filters (APFs) of 3P-4W UPQC mitigate the current and voltage based distortions, respectively. A simple control algorithm based on Unit Vector Template Generation (UVTG) is used as a control strategy of UPQC for mitigation of different PQ problems. In this control scheme, the current/voltage control is applied over the fundamental supply currents/load voltages instead of fast changing APFs currents/voltages, thereby reducing the effects of computational delay and the required sensors. The performance of the proposed topology of UPQC is analyzed through simulations results using MATLAB software with its Simulink and Power System Block set toolboxes.
IEEE recommended practices and requirements for harmonic control in electric power system, IEEE Standard 519, 1992.
IEEE Recommended Practice for Monitoring Electric Power Quality, IEEE Standard 1159, 1995.
E. W. Gunther and H. Mehta, “A survey of distribution system power quality”, IEEE Trans. Power Delivery, vol.10, No.1, pp.322-329, Jan.1995.
A. C. Liew, “Excessive neutral current in three-phase fluorescent lighting circuits,” IEEE Trans. Ind. Appl., vol.25, no.4, pp.776-782.Jul. /Aug. 1989.
T. M. Gruzs, “A survey of neutral currents in three-phase computer systems” ,IEEE Trans. Ind. Appl.,vol.26,no.4,pp.719-725,Jul./Aug.1990.
P. Jayaprakash , B. Singh and D. P. Kothari , “DSP based implementation of a three-phase four-wire DSTATCOM for voltage regulation and power quality improvement ,” in Proc. IEEE IECON '09, pp.3660-3665.
T. Zhili , L. Xun , C. Jian , K. Yong and D. Shanxu , “A direct control strategy for UPQC in three-phase four-wire system,” in Proc.2006 IEEE Conf. on Power Electron. and Motion Control ,vol.2,pp.1-5.
V. Khadkikar and A.Chandra , “A Novel Structure for Three-Phase Four-Wire Distribution System Utilizing Unified Power Quality Conditioner (UPQC),”IEEE Trans. Industry Appl.,vol.45,pp.1897-1902,2009.
L. Xun , Z. Guorong , D. Shanxu and C. J. Chen, “Control Scheme for Three-Phase Four-Wire UPQC in a Three-Phase Stationary Frame,” in Proc. 2007 IEEE/IECON, pp.1732-1736, 2007.
A. Ghosh, A. K. Jindal and A. Joshi, “A unified power quality conditioner for voltage regulation of critical load bus,” in Proc. 2004 IEEE Power Eng. Society General Meeting, , vol.1, pp471-476.
B. Singh and Venkateswarlu, “A Simplified Control Algorithm for Three-Phase Four-Wire Unified Power Quality Conditioner,” Journal of Power Electronics, vol.10, No.1, January2010.
G. Chen , Y. Chen and K. M. Smedley, “Three-phase four-leg active power quality conditioner without references calculation,” in Procd.2004 IEEE APEC '04, vol.1, pp.587-593, 2004.
V. Kumar , P. Agarwal and H. O. Gupta , “A Simple Control Strategy for Unified Power Quality Conditioner Using Current Source Inverter,” in Procd 2007 IPEC2007, pp.1219-1223.
M. Levin, “Combined phase-shifting directional zero phase sequence current filter and method for using thereof,” U.S.Patent 5 416 688, May 16, 1995.
K. L. Parker, “Active neutral current compensator,” U.S.Patent 5 574356, Nov.12, 1996.
H. Fugita and H. Akagi, “Voltage regulation performance of a shunt active filter intended for installation on a power distribution system,” IEEE Trans. Power Elect., vol.22, no.1, pp.1046-1053,May2007.
P. Enjenti, W. Shireen, P. Packebush and I. Pitel, “Analysis and design of a new active power filter to cancel neutral current harmonics in three-phase four-wire electric distribution systems,” IEEE Trans. Ind. Appl.,vol.30,no.6,pp.1565-1572,Nov./Dec.1994.
B. N. Singh, P. Rastgoufard , B. Singh , A. Chandra and K. A. Haddad, “Design, simulation and implementation of the three pole/four pole topologies for active filters,” in Proc. Inst. Elect. Engg. Electr. Power Appl., Jul.2004, vol.151, no.4, and pp.467-476.