LQR CONTROL APPROACH APPLIED TO UNINTERRUPTIBLE POWER SUPPLY (UPS)
Résumé
This paper presents a control strategy applied to high power uninterruptible power supplies with a low switching frequency. In
the controller design, the gains are determined by minimizing a cost function, which reduces the tracking error and smoothes
the control signal. A recursive least square estimator identifies the parameters model at different load conditions. Then the
linear quadratic controller gains are adapted periodically. The output voltage is the only state variable measured.The other state
variables are obtained by estimation process. Simulation results show that the proposed control strategy offers good
performances for either linear and non-linear loads with low total harmonic distortions (THD) even at low frequencies making
it very useful for high power applications.
Références
IEEE
Recommended
Practice
for
Emergency
and
Standby
Power
Systems
for
Industrial
and
Commercial Applications, IEEE-446- 1995, 1995.
[2]
A. Kawamura and T. Yokoyama, "Comparison of Five
Control Methods for Digitally Feedback Controlled
PWM Inverters," in Proceedings of the 1991 EPE
Conference, pp. 035-040.
[3]
T.
Haneyoshi
and
A.
Kawamura,
"Waveform
Compensation
of
PWM
Inverter
with
Cyclic
Fluctuating
Loads,"
IEEE
Trans.
Industrial
Application, vol. 24, no. 4, July. 1988, pp. 582-589.
[4]
V .F Montagner and E.G Carati, "An Adaptive Linear
Quadratic
Regulator
with
Repetitive
Controller
Applied
to
Uninterruptible
Power
Supplies,"
in
Proceedings of the 2000 IEEE Industry Applications
Conference, pp. 2231-2236.
[5]
S. Karam and J. K. Mahdi, "Application of Adaptive
LQR with Repetitive Control for UPS systems," in
Proceedings of the 2003 IEEE Industry Applications
Conference, pp. 1124-1129.
[6]
J. Cho, S. Lee, H. Mok, and G. Choe, "Modified
Deadbleat Controller For UPS With 3-phase PWM
Inverter, " in Conf. Rec. IEEE-IAS Annu. Meeting,
1999, pp. 2208-2215.
[7]
S. Buso, S. Fasolo, and P. Mattavelli, "Uninterruptible
Power Supply Multiloop Control Employing Digital
Predictive
Voltage
and
Current
Regulators,
"in
Proceding. IEEE APEC, 2001, pp. 907-913.
[8]
Y. Y. Tzou, R. S. Ou, S. L. Jung, and M. Y. Chang,
"High Performance Programmable AC Power Source
With Low Harmonic Distortion Using DSP-based
Repetitive Control Technique, " IEEE Trans Power
Electron, July 1997, vol. 12, pp. 715-725.
[9]
U. B. Jensen, P. N. Enjeti, and F. Blaabjerg, "A new
space vector based control method for UPS systems
powering an onlinear performance programmable AC
power source with low harmonic distortion using
DSP-based repetitive control technique, " IEEE Trans.
Power Electron, July 1997, vol. 12, pp. 715-725.
[10] M.J. Ryan, W.E. Brunsicle, and R.D. Lorenz, "Control
Topology Option For a Single-Phase UPS Inverters,"
IEEE Trans. Industrial Application, Mars. 1997, vol.
33, no. 4, pp. 493-501.
[11] A.V. Jouanne, P.N. Enjeti, and D.J. Lucas, "DSP
Control
Of
High
Power
UPS
Systems
Feeding
Nonlinear loads," IEEE Trans. Industrial Electronics,
Feb. 1996, vol. 43, pp. 121-125.
[12] P.Mattavelli, "Synchronous –Frame Harmonic Control
For High Performance A Power Supplies," IEEE
Trans. Industrial Application, May. 2001, vol. 37, pp.
864-872.
[13] K.Ogata,
Discrete-Time
Control
Systems,
Prentice-
Hall: 1987.
[14] K.J. Astrom and V.E. Wittenmark, Adaptive Control,
Second edition Prentice Hall Inc: 1995.
[15] G. Welch and G. Bishop, An introduction to the
Kalman filter, University of North Carolina at Chapel
Hill, NC 27599-3175: 2003.
