Deadbeat control system with novel neutral-point balancing scheme for Active Power Filters

In this paper a deadbeat control system with a novel 3-dimension (3-D) space vector modulation scheme for 3-phase 4-wire tri-level three-leg Active Power Filter (APF) is proposed. To improve the compensation effect a repetitive harmonic predictor is utilized to predict the harmonic current and a state observer is used to estimate the output currents of the APF at the sampling instants in the deadbeat control system. For a 3-phase 4-wire tri-level three-leg APF the direct current (DC) bus neutral-point unbalancing is an inherent problem. To date there has not been an effective method to solve this problem. In this paper, a detailed discussion of neutral-point unbalancing problem is presented and a conception named Neutral-Point Control Grade (NPCG) is proposed for the first time, to describe the affected extent of the neutral-point voltage by the space vectors. Then a neutral-point controllable 3-D space vector modulation scheme, which is based on the NPCGs, is proposed in alpha-beta-0 coordinates. The simulation result verifies the correctness and effectiveness of the proposed control strategy. A comparison focusing on the neutral-point voltage between the proposed NPCGs based 3-D modulation scheme and another advanced 3-D modulation scheme is also presented in this paper.

[1]  Man-Chung Wong,et al.  Cylindrical coordinate control of three-dimensional PWM technique in three-phase four-wired trilevel inverter , 2003 .

[2]  J. I. Leon,et al.  A SVM-3D generalized algorithm for multilevel converters , 2003, IECON'03. 29th Annual Conference of the IEEE Industrial Electronics Society (IEEE Cat. No.03CH37468).

[3]  Zhan Changjiang.  Control of tri-level shunt power quality conditioners , 2000 .

[4]  Chi-Seng Lam,et al.  A 3-D generalized direct PWM for 3-phase 4-wire APFs , 2005, Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference, 2005..

[5]  Nicholas Jenkins,et al.  Four-wire dynamic voltage restorer based on a three-dimensional voltage space vector PWM algorithm , 2003 .

[6]  M.G. Villalva,et al.  Current controller with artificial neural network for 3-phase 4-wire active filter , 2004, 2004 IEEE 35th Annual Power Electronics Specialists Conference (IEEE Cat. No.04CH37551).

[7]  Subhashish Bhattacharya,et al.  Active filter solutions for utility interface of industrial loads , 1996, Proceedings of International Conference on Power Electronics, Drives and Energy Systems for Industrial Growth.

[8]  Man-Chung Wong,et al.  Application of a three-level NPC inverter as a three-phase four-wire power quality compensator by generalized 3DSVM , 2006 .

[9]  G. Chang,et al.  A new approach for optimal shunt active power filter control considering alternative performance indices , 2006, IEEE Transactions on Power Delivery.