Improved single-phase line-interactive UPS

An improved single-phase line-interactive uninterruptible power supply (UPS) is proposed for low-power applications with low cost. The proposed UPS is comprised of two push-pull converters based on a low-voltage battery for reduced cost: one in series with the input and the other in parallel with the load. In the presence of input power, the UPS acts as an output voltage regulator and at the same time as an active filter while charging the battery. In case of loss of input power, the UPS supplies a regulated sinusoidal voltage to the load, drawing power from the battery. The series converter compensates only a small percentage of the input voltage carrying the input current and, therefore, a reduced rating is made. The parallel converter always supplies a nominal voltage and makes a seamless transition to backup mode. In the voltage determination of the parallel converter, the nominal voltage is derived using the feedback linearization concept and then a perturbed voltage is determined for the reactive power control or output voltage regulation. Experimental results obtained from a 1-kVA prototype are discussed.

[1]  S. Moran,et al.  A line voltage regulator/conditioner for harmonic-sensitive load isolation , 1989, Conference Record of the IEEE Industry Applications Society Annual Meeting,.

[2]  T. Kawabata,et al.  Three phase parallel processing UPS using multi-functional inverter , 1989, Conference Record of the IEEE Industry Applications Society Annual Meeting,.

[3]  H.-L. Jou,et al.  New single-phase active power filter , 1994 .

[4]  S. J. Chiang,et al.  A three-phase multi-functional battery energy storage system , 1994, Proceedings of IECON'94 - 20th Annual Conference of IEEE Industrial Electronics.

[5]  T. G. Habetler,et al.  A novel on-line UPS with universal filtering capabilities , 1995 .

[6]  Johan Enslin,et al.  A new unified approach to power quality management , 1995 .

[7]  Hurng-Liahng Jou,et al.  A new UPS scheme provides harmonic suppression and input power factor correction , 1995, IEEE Trans. Ind. Electron..

[8]  S. J. Chiang,et al.  Three-phase multifunctional battery energy storage system , 1995 .

[9]  T. G. Habetler,et al.  Combined deadbeat control of a series-parallel converter combination used as a universal power filter , 1995 .

[10]  Prasad N. Enjeti,et al.  DSP control of high-power UPS systems feeding nonlinear loads , 1996, IEEE Trans. Ind. Electron..

[11]  C. Y. Hsu,et al.  A new single-phase active power filter with reduced energy-storage capacity , 1996 .

[12]  S. Rathmann,et al.  New generation UPS technology, the delta conversion principle , 1996, IAS '96. Conference Record of the 1996 IEEE Industry Applications Conference Thirty-First IAS Annual Meeting.