High-performance Control of UPS Inverters Using a B-Spline Network

The purpose of a voltage controller for UPS inverters is to produce stable and regulated output voltage with low distortion under all loading conditions, especially under nonlinear loads. In this paper, a B-spline network controller that is easy to implement is proposed for UPS inverters. A modified weights-updating law with 'forgetting factor' is introduced to increase the robustness of the scheme against measurement noise, initialization error and/or variation of system dynamics due to parameter drifts. Detailed design formulas for two parameters of B-spline network: the B-spline support width and the learning gain are given based on stability analysis in frequency domain. A parallel PD controller is also adopted as feedback control in order to improve the dynamic performance. Experimental results show that the proposed controller can achieve very low total harmonic distortion and fast error convergence under different loads even with only one sensor. Moreover, the proposed controller also can obtain fast dynamic response

[1]  Karl Johan Åström,et al.  Computer-Controlled Systems: Theory and Design , 1984 .

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

[3]  Ying-Yu Tzou,et al.  DSP-based multiple-loop control strategy for single-phase inverters used in AC power sources , 1997, PESC97. Record 28th Annual IEEE Power Electronics Specialists Conference. Formerly Power Conditioning Specialists Conference 1970-71. Power Processing and Electronic Specialists Conference 1972.

[4]  Dehong Xu,et al.  Analogue implementation of a neural network controller for UPS inverter applications , 2002 .

[5]  Astrom.  Computer Controlled Systems , 1990 .

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

[7]  Michael Unser,et al.  Splines: a perfect fit for signal and image processing , 1999, IEEE Signal Process. Mag..

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

[9]  D. Srinivasan,et al.  High-performance control of a UPS inverter through iterative learning based on zero-phase filtering , 2004, 30th Annual Conference of IEEE Industrial Electronics Society, 2004. IECON 2004.

[10]  Mohamad Adnan Al-Alaoui,et al.  A class of second-order integrators and low-pass differentiators , 1995 .

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

[12]  S. Arimoto,et al.  Robustness of P-type learning control with a forgetting factor for robotic motions , 1990, 29th IEEE Conference on Decision and Control.

[13]  Humberto Pinheiro,et al.  A modified discrete control law for UPS applications , 2003 .