An improvement in the performance of unified power quality conditioner using dc-link voltage control

The dc link voltage of the unified power quality conditioner (UPQC) is maintained at certain preset value during the steady state. However the dc link voltage can significantly deviate from its reference during a transient event, caused by load connection/disconnection or/and supply side voltage sag/swell. During such transients, due to significant deviation in the dc link voltage, the series injected voltage magnitude varies, causing fluctuations in the load voltage magnitude. A suitable hysteresis controller is proposed for the series compensator in order to adjust the series injected voltage for a constant deviation in the dc link voltage. Besides, an adaptive dc link voltage controller is proposed which limits the dc link voltage deviation during the transient conditions. The effectiveness of the proposed control schemes have been demonstrated through simulations.

[1]  A. Kazemi,et al.  Introducing a new method for UPQC control to solve the power quality problems , 2008, 2008 3rd IEEE Conference on Industrial Electronics and Applications.

[2]  M. J. Samotyj,et al.  Voltage sags in industrial systems , 1991, Conference Record. Industrial and Commercial Power Systems Technical Conference 1991.

[3]  Hirofumi Akagi.  Trends in active power line conditioners , 1994 .

[4]  A. Chandra,et al.  Application of UPQC to protect a sensitive load on a polluted distribution network , 2006, 2006 IEEE Power Engineering Society General Meeting.

[5]  Kamal Al-Haddad,et al.  An improved control algorithm of shunt active filter for voltage regulation, harmonic elimination, power-factor correction, and balancing of nonlinear loads , 2000 .

[6]  Malabika Basu,et al.  Comparative evaluation of two models of UPQC for suitable interface to enhance power quality , 2007 .

[7]  Bhim Singh,et al.  A comparison of single-phase p-q theory and UVT based control algorithms for single-phase UPQC , 2010, 2010 Annual IEEE India Conference (INDICON).

[8]  Jul-Ki Seok,et al.  Control of series active power filters compensating for source voltage unbalance and current harmonics , 2004, IEEE Transactions on Industrial Electronics.

[9]  Ward Jewell,et al.  Effects of harmonics on equipment , 1993 .

[10]  Malabika Basu,et al.  A 12-kVA DSP-Controlled Laboratory Prototype UPQC Capable of Mitigating Unbalance in Source Voltage and Load Current , 2010, IEEE Transactions on Power Electronics.

[11]  Malabika Basu,et al.  dc link voltage control of UPQC for better dynamic performance , 2011 .