Design of the Feed Forward Controller in Digital Method to Improve Transient Characteristics for Dynamic Voltage Restorers

동적전압보상기의 과도특성을 개선하기 위한 디지털방식의 전향제어기 설계

  • 김효성 (천안공업대학 제어계측과) ;
  • 이상준 (㈜로템 중앙연구소) ;
  • 설승기 (서울대학교 전기컴퓨터공학부)
  • Published : 2004.06.01

Abstract

This paper discusses how to control the compensation voltages in dynamic voltage restorers (DVR). On analyzing the power circuit of a DVR system, control limitations and control targets are presented for the voltage compensation in DVRs. Based on the preceded power stage analysis, a novel controller for the compensation voltages of DVRs is proposed by a feed forward control scheme. This paper discusses also the time delay problems in the control system of DVRs. Digitally controlled DVR systems normally have control delay at amount of one sampling time of the control system and a half of the switching period of the DVR inverter. The control delay in digital controllers increases the dimension of the system transfer function one degree higher, which makes the control system more complicate and more unstable. This paper proposes a guide line to design the control gain, appropriate output filter parameters and inverter switching frequency for DVRs with digital controllers. Proposed theory is verified by an experimental DVR system with a full digital controller.

본 논문은 동적전압보상기(DVR)의 제어를 위한 우수한 성능의 디지털제어기를 제시하고 제어이득(Control Gain)의 설정에 관하여 논한다. DVR계통의 전력회로를 분석하여 DVR의 운전한계를 찾고 그에 따른 제어목표 및 제어기 구조를 제시한다. 디지털 제어기는 인버터의 PWM 스위칭과 함께 제어시스템의 시간지연을 야기한다. 이러한 시간 지연은 제어시스템의 전달함수를 1차수 높게 하여 제어시스템을 더한층 복잡하고 불안정하게 한다. 본 논문은 제어기의 시간지연을 고려하여 제안된 제어기의 이득을 설정하는 방법을 제시하고 인버터의 스위칭 주파수와 관련하여 출력측 필터요소의 설계지침을 제시한다. 제안된 설계방법에 의하여 전디지털화(Full Digital Control) 된 DVR 시스템을 제작하여 이론을 검증한다.

Keywords

References

  1. Proc. of the IEEE International Symposium on Industrial Electronics(ISIE) Three-Phase Static Series Voltage Regulator Control Algorithms for Dynamic Sag Compensation G.Joos
  2. Conf. Rec. IEEE-APEC Annu. Meeting Control Strategies for Dynamic Voltage Restorer Compensating Voltage Sags with Phase Jump J.Nielson;F.Blaabjerg;N.Mohan
  3. IEEE Trans. Power Electronics v.19 no.3 The Novel Control Algorithm for Static Series Compensators by use of PQR Power Theory S.J.Lee;S.K.Sul;H.Kim;F.Blaabjerg
  4. 전력전자학회 논문지 v.8 no.5 PQR 순시전력이론에 의한 동적전압보상기의 보상전압 결정 김효성;이상준;설승기
  5. EEE Trans. Industrial Electronics v.45 no.5 Comparison of Current Control Techniques for Active Filter Applications S.Buso;L.Malesani;P.Mattavelli
  6. IEEE Trans. Power Electronics v.6 no.1 Digital Control of Three-Phase PWM Inverter with LC Filter T.Kawabata;T.Miyashita;Y.Yamamoto
  7. IEEE Trans. Power Electronics v.11 no.1 Deadbeat Control of a Three-Phase Inverter with an Output LC Filter O.Kueker
  8. Conf. Rec. IEEE-APEC Ann. Meeting A Synchronous-Frame Controller for a Single Phase Sine Wave Inverter M.Ryan;D.Lorenz
  9. Conf. Rec. IEEE-PESC A New Control Strategy for Instantaneous Voltage Compensator Using 3-Phase PWM Inverter S.Lee;Y.Chae;J.Cho;G.Choe;H.Mok;D.Jang
  10. IEEE Trans. Power Electronics v.17 no.5 Performance Improvement of the Dynamic Voltage Restorer with Closed-Loop Load Voltage and Current-Mode Control M.Vilathgamuwa;A.Perera;S.Choi
  11. Conf. Rec. IEEE-PCC2002 An Adaptive Current Control Technique for Active Filters S.Fukuda;Y.Fukuwara;H.Kamiya