A.Y.K. Wong

Bio: A.Y.K. Wong is an academic researcher. The author has contributed to research in topics: AC power & Band-stop filter. The author has an hindex of 1, co-authored 1 publications receiving 16 citations.

Harmonic compensation for nonlinear loads by active power

Abstract: This paper studies a single phase shunt active power filter (APF) using a bi-directional full-bridge converter with capacitive energy storage to compensate for the harmonics generated by nonlinear loads. The usage of a capacitor as a reactive power source for the APF simplifies the circuitry. The harmonic current reference is obtained by feeding the load current signal into a 50 Hz notch filter. The simple and fast hysteresis control strategy involving only a few analog and logic components makes it attractive for the low power domestic application. The usefulness of the proposed control algorithm is confirmed by simulation as well as by experimental results.

Reciprocal effects of the distorted wind turbine source and the shunt active power filter: full compensation of unbalance and harmonics under ‘capacitive non-linear load’ condition

Abstract: Available compensating algorithms for shunt active power filters (SAPFs) and unified power quality conditioner perform somehow improperly in practice under certain circumstances. Typical examples could be any distorted `non-linear loads' showing low impedances at certain frequencies; also, there are technological limitations for the SAPF in modulating switching frequencies, including microcontroller processing speed, the employed control and modulation techniques, delays and so on. This study proposes an advanced universal power quality conditioning system (AUPQS) to fine tune the available solutions for generating purely sinusoidal wind turbine-end currents under both distorted-unbalanced load-terminal voltages and non-linear load conditions (capacitive loads leave much worse consequences than those of the inductive). It is shown that both series and SAPF are capable of full compensation of microgrid by the SAPF using the advanced generalised theory of instantaneous power. Meanwhile, the resultant source currents could be somehow non-sinusoidal. However, the proposed AUPQS will be able to fully eliminate the consequence of voltage asymmetry and unbalanced waveforms on the SAPF, generated because of the wind turbine operation by performing certain corrections on these solutions. Moreover, an independent single-phase rectifier is proposed at the load-end to regulate DC-link voltage. Effectiveness of the proposed AUPQS is confirmed by Simulink simulations.

Zero-sequence harmonics current minimization using zero-blocking transformer and shunt LC passive filters

Abstract: This paper presents a method for zero-sequence harmonics current minimization using zero-sequence blocking transformer and passive filters. The zero-sequence blocking transformer placed in series with the source provides high zero-sequence impedance while the shunt- passive filters placed parallel with the load provides low zero-sequence impedance. Thus, the zero-sequence harmonics currents tend to flow through the filter instead of the source. The effectiveness of this method depends on the ratio of zero-sequence blocking transformer impedance to filter impedance. This method offers relatively low-cost solution, while the passive components used make this. method relatively more reliable. The analysis is confirmed by simulation. The simulation result is verified through experiment work.

Implementation of shunt active power filter using sliding mode controller

Abstract: In this paper control of shunt active power filter with sliding mode controller is considered. The compensation by shunt active power filter involves harmonics mitigation due to three phase non linear loads. The sliding mode controller is used to regulate voltage of the capacitor used in inverter. The sliding mode controller improves the dynamic response of the system and provides faster convergence. The performance of the sliding mode controller is compared with the conventional PI controller. The realization of the system is implemented for balanced and unbalanced load conditions using MATLAB/Simulink. From the analysis it can be observed that the shunt active power filter with sliding mode controller gives a better response than the conventional PI controller. The simulation results prove the effectiveness of the proposed system.

Analysis and implementation of shunt active power filter based on synchronizing enhanced PLL

Abstract: This paper addresses the analysis and software implementation of synchronizing circuit enhancement phase locked loop (EPLL) designing for use in controller of shunt active power filter (SAPF) for harmonics mitigation Advantages of EPLL structure over conventional PLL's including its capability to made and maintain zero phase difference between input signal and voltage controlled oscillator (VCO) output signal Proposed PLL architecture is extract individual harmonic component and track amplitude as well as phase angle of its input signal The extracted currents are used for reference current generation in SAPF The shunt active power filter is implemented using EPLL and investigated for three phase non-linear loads using MATLAB/Simulink platform Simulation results show effectiveness and performance robustness synchronization using EPLL for improve power quality

A novel control strategy for capacitor voltage regulation of Unified Power Quality Conditioner using Integral plus Sliding Mode Controller

Abstract: Increased use of non-linear loads in industries causing voltage and current distortions. Unified Power Quality Conditioner (UPQC) is used at Distribution level to compensate voltage as well as current distortion problems at a time. In order to ensure the better operation of UPQC, the DC-Link capacitor voltage must be maintained constant. Traditional Pi-controller shows overshoot in response. Also, the Sliding Mode Controller (SMC) designed using traditional approach exhibits steady-state error. This offset can be removed by adding a constant in SMC law. But this approach can't work for UPQC system, when load is change. In this paper, a novel capacitor voltage regulator is proposed using Integral plus Sliding Mode Control technique. The proposed controller has the inherent advantages like has very low Settling Time with no overshoot. This controller completely eliminates steady-state error. The simulation results are given considering various control strategies, shows validation of proposed technique.