Wenjin Dai

Bio: Wenjin Dai is an academic researcher from Nanchang University. The author has contributed to research in topics: AC power & Active filter. The author has an hindex of 2, co-authored 4 publications receiving 13 citations.

A new method for harmonic and reactive power compensation

Abstract: This paper presents a method for the harmonic and reactive power compensation with an adaptive hysteresis band current controller and a control algorithm for active power filter (APF) to eliminate the harmonics and compensate the reactive power in three-phase thyristor bridge rectifier. The adaptive hysteresis band current controller is adapted to the active power filter (APF). And it can change the hysteresis bandwidth according to modulation frequency, supply voltage, dc capacitor voltage and slope of the iC* reference compensator current wave. Until now, all of the studies have been carried out through detail digital dynamic simulation with the MATLAB Simulink Power System Toolbox. The results of simulation study of the new APF control technique and algorithm presented in this paper is found quite satisfactory in eliminating harmonics and reactive power components in utility current.

A new study for harmonic suppression and reactive power compensation

Abstract: This paper presents a new method for harmonic and reactive power compensation with an artificial neural network(ANN) controller and a new control algorithm for active power filter (APF) to eliminate harmonics and compensate the reactive power of three-phase thyristor bridge rectifier. The artificial neural network (ANN) current controller is adapted to active power filter (APF) and the current controller based on modified hysteresis current controller is used to generate the firing pulses. All of the studies have been carried out through detail digital dynamic simulation using the MATLAB Simulink power system toolbox. The results of simulation study of new APF control technique and algorithm presented in this paper are found quite satisfactory to eliminate harmonics and reactive power components from utility current.

Design of single phase BOOST-PFC converter with fast voltage regulator

Abstract: In this paper, a simple and robust voltage controller with single phase BOOST-PFC converter is proposed, which can improve voltage dynamics. The conventional control of the PFC converter requires filtering voltage ripples (referring to AC component in output DC voltage) in order to reduce the total harmonic distortion (THD) in the input current. But this filtering action significantly reduces the effective of voltage regulation bandwidth, resulting in slow voltage dynamics. The proposed project can cancel the voltage ripples on the DC voltage feedback path without any filtering action, and so allows design of large bandwidth voltage control loop. It can eliminate large overshoots and undershoots of output voltage during the transients. It was proved by the simulation and experiment.

Current control based on three-phase shunt hybrid active power filter case study

Abstract: In this paper, three-phase four-leg shunt hybrid active power filter is proposed to suppress harmonic, neutral line current, which is different from the common instantaneous reactive power theory (IRP). A predictive current control method based on the calculation of transfer function is used in this paper. All simulations are performed by using Matlab-Simulink Power System Blockset, and the simulation results show the validity of this method.

Control Techniques for Active Power Filters

Abstract: With the widespread use of harmonic-generating devices, the control of harmonic currents to maintain a high level of power quality is becoming increasingly important. An effective way for harmonic suppression is the harmonic compensation by using active power filter. This paper presents a comprehensive survey of active power filter (APF) control strategies put forward recently. It is aimed at providing a broad perspective on the status of APF control methods to researchers and application engineers dealing with harmonic suppression issues. Many control techniques have been designed, developed, and realized for active filters in recent years. We classify all control methods into two main groups. The first group is reference parameter detection method. This can be done in either the time or frequency domain. The second group is derivation methods of the switching functions for active filters. In this paper, we mainly discuss the second group and its application. The paper also investigates some possibilities of new approach to control active power filters.

A novel hysteresis bandwidth (NHB) calculation to fix the switching frequency employed in active power filter

Abstract: Variable switching process is the main issue in practical implementation of fixed band hysteresis current controller in active power filters (APF) that increases the switching frequency and switching losses in power systems. Preventing this case, the Adaptive Hysteresis Current Control (AHCC) has been introduced and developed by many researchers. By this way, The Hysteresis Band (HB) will change adaptively by system parameters in order to control the switching speed and fix the switching frequency. In this paper a revisory method for the hysteresis bandwidth calculation procedure is proposed that makes switching frequency invariable significantly. The APF Simulations using proposed method (NHB) in Matlab/Simulink environment has been done. Results including switching frequency and current source TDH have been given to prove the efficiency of this method.

Geometrical approach for a predictive current controller applied to a three-phase two-level four-leg inverter

Abstract: Current model predictive control for a grid-connected four-leg voltage source converter application is presented in this paper The solution of the optimum criterion defined by predictive control is considered as the reference current This current will be applied based on projections of the different current control vectors corresponding to the switches states Geometrical properties of the predicted current projections are used to achieve a current control strategy operating at fixed switching frequency A laboratory model of the four-leg converter and its load has been constructed and its performance has been tested through experiments

Current Control of the Isolated Self-Excited Induction Generator using Shunt Active Filter

Abstract: The Self Excited Induction Generator (SEIG) is an isolated power source whose terminal voltage and frequency are controlled by the excitation of the capacitance or the load impedance. This paper presents a method for calculating the minimum excitation capacitance using the equivalent circuit approach for analyzing the steady state operation of SEIG. A new strategy based on an active power filter (APF) for controlling the current and power quality of the self excited induction generator (SEIG) is also presented in this paper. The shunt active power filter was implemented using a three phase PWM current controlled voltage source inverter (VSI) and connected to the wind generator and loads in order to compensate the current harmonics and reactive power. The PWM-VSI gate control signals are derived from hysteresis band current controller. The proposed active filter proved to play an important role and give good dynamic response and robust behavior upon changes in load parameters. This investigation demonstrated that power average control strategy can facilitate the improvement of the power quality. The proposed control method extracts fundamental (reference) components of the source current for the shunt active power line conditioners for nonlinear and unbalanced loads. The Power average approach additionally maintains the voltage of the capacitor (of the PWM inverter) nearly constant without any external control circuit. The shunt APF in conjunction with the proposed controller performs perfectly under different steady state and transient conditions. The simulation results with nonlinear loads and unbalanced loads have showed the effectiveness of the proposed scheme for harmonic reduction in Wind based Power Generation.