An improved deadbeat control for UPS using disturbance observers

A digital control technique for the inverter stage of uninterruptible power supplies is proposed, which is based on a predictive regulator on both output voltage and inductor current. Its aim is to achieve a deadbeat dynamic response for the controlled variables (output voltage and inverter current). Besides the linear state feedback which allocates system poles at the origin so as to achieve deadbeat response for all state variables, the use of a disturbance observer for the estimation of the load current and of any other source of errors (such as dead-times, parameter, and model mismatches) is investigated. The proposed solution is able to guarantee a fast dynamic response and also a precise compensation of any source of unpredictable disturbance. Moreover, with a proper design of observer parameters, it is possible to reduce control sensitivity to model uncertainties, parameter mismatches, and noise on sensed variables, which usually characterizes existing deadbeat control techniques. Finally, the control algorithm is quite simple and requires only the measurements of the output voltage and inductor current. Experimental results on a single-phase 2 kVA prototype show the effectiveness of the proposed approach.

[1]  Atsuo Kawamura,et al.  Disturbance observer based fully digital controlled PWM inverter for CVCF operation , 1994 .

[2]  Ying-Yu Tzou,et al.  High-performance programmable AC power source with low harmonic distortion using DSP-based repetitive control technique , 1997 .

[3]  Takao Kawabata,et al.  Dead beat control of three phase PWM inverter , 1987 .

[4]  Y. Ito,et al.  Microprocessor based robust digital control for UPS with three-phase PWM inverter , 1995 .

[5]  Hyung-Soo Mok,et al.  Modified deadbeat digital controller for UPS with 3-phase PWM inverter , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).

[6]  Frede Blaabjerg,et al.  A new space vector based control method for UPS systems powering nonlinear and unbalanced loads , 2000, APEC 2000. Fifteenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.00CH37058).

[7]  Y. Dote,et al.  Intelligent control, power electronic systems , 1999, IEEE Power Engineering Review.

[8]  Hasan Komurcugil,et al.  Deadbeat control method for single-phase UPS inverters with compensation of computation delay , 1999 .

[9]  Atsuo Kawamura,et al.  Deadbeat controlled PWM inverter with parameter estimation using only voltage sensor , 1988, 1986 17th Annual IEEE Power Electronics Specialists Conference.

[10]  Robert D. Lorenz,et al.  Control topology options for single-phase UPS inverters , 1996, Proceedings of International Conference on Power Electronics, Drives and Energy Systems for Industrial Growth.

[11]  Osman Kukrer,et al.  Deadbeat control of a three-phase inverter with an output LC filter , 1996 .

[12]  Atsuo Kawamura,et al.  Waveform compensation of PWM inverter with cyclic fluctuating loads , 1988 .

[13]  F. Blaabjerg,et al.  A new control method for 400 Hz ground power units for airplanes , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).