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ABSTRACT: The unbalanced and nonlinear loads could result in a significant neutral current in the three-phase four-wire distribution power system. This paper proposes a novel neutral line active power filter (APF) system based on the special connection of the transformers and single-phase inverter. The theory analysis and computer simulations show that: (a) control system would be easy to implement due to only one single-phase inverter exists, (b) harmonic compensation efficiency is higher than 90% and the fundamental current in the neutral line would not be affected, (c) the VA rating and cost of the inverter are significantly reduced compared to the conventional three-phase four-wire APF system.
Power Electronics and Drive Systems, 2009. PEDS 2009. International Conference on; 12/2009
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ABSTRACT: This paper analyzes the characteristic of singlephase converter system and establishes the active power and reactive power model in d-q axis, which is the same with the three-phase system in d-q axis and could employ decoupling feedback control for reactive compensation and active power control. For realizing d-q transformation in single-phase system, a new orthogonal decomposition method with sliding window filter (SWF) is presented. While, for the sake of SWF, the coupling between active power and reactive power could not be eliminated completely, which leads to poor dynamic process in control system and significant distortion in compensation current. For overcoming these shortages, this paper presents a distortion correction based control strategy, which not only could improve the control system dynamic characteristics, but also eliminate compensation current's distortion. At last, si mulations with different control strategies demonstrate the validity and superiority of proposed control strategy.
Power Electronics and Drive Systems, 2009. PEDS 2009. International Conference on; 12/2009
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ABSTRACT: The repetitive control has been widely used in grid connected voltage source converters, such as uninterruptible power supplies (UPS), photovoltaic inverter (PV) and active power filter (APF). This paper introduces a new repetitive control strategy in the APF system; the proposed control strategy has a forgetting factor (FF), which could improve control system robustness. Control system stability and convergence analysis points out that control system characteristics depend on characteristic expression, which is essential for controller design. Appropriate design of this characteristic expression could make control system have good stability and fast convergence rate. Combination of industrial application, this paper presents a controller analysis and design methods, at last, simulations and experiment results demonstrate the validity of proposed repetitive control strategy.
Power Electronics and Drive Systems, 2009. PEDS 2009. International Conference on; 12/2009
