Three-phase four-wire shunt active filter control strategies

Shunt active power filters are the most viable solution for solving current harmonic, reactive power compensation, and load unbalancing problems widely presented in electrical distribution systems. In this article, development and implementation of a digital signal processor based three-phase four-wire shunt active power filter are analyzed to compensate non-linear and unbalanced loads under non-ideal supply voltages conditions. The proposed algorithm is divided into two parts, the first associated with the calculation of the positive-sequence component of unbalanced supply voltage and second deriving a simple and attractive fundamental extraction filter to extract the fundamental frequency component from distorted positive-sequence voltage. Average power and DC-link energy balance methods are used to calculate peak value of the supply current, which is required to flow from source to load. The behavior and effectiveness of the proposed control algorithm has been verified by simulation using MATLAB/Simulink (The MathWorks, Natick, Massachusetts, USA) environment for different cases of supply voltage. A laboratory prototype has been developed to verify the simulation results. The control scheme is realized using a TMS320F28335 floating-point digital signal processor (Texas Instruments, Dallas, Texas, USA) based system. It is found that simulated and experimental harmonic spectral performances are in compliance with the recommendations about harmonic limits imposed by the IEEE-519 Standard.

Usage of Active power filters is increased in this moderen era as they are capable to reduce harmonics effectively. Shunt Active Filters are proven to diminish harmonics compared to all other devices. Many control strategies has been developed till date to control Shunt Active Power filter. In soft computing techniques generally fuzzy logic has been used with mamdani type of fuzzy logic controller. This paper presents comparison of mamdani and TS type fuzzy logic controller to control the three-phase shunt active power filter. Fuzzy logic method is used to tune PID controller to autotune controller. Instantaneous Reactive Power theory is implemented to generate reference currents. Simulation is done in MATLAB to verify the results.

Active power filters are the emerging devices, which can diminish harmonic pollution effectively. Most of the proposed control strategies for power quality improvements have been reviewed with regard to performance and implementation. It has been seen that there has been a significant increase in interest of active power filters and its control methods. Mathematical model of Shunt Active Power filter is implemented with Instantaneous Reactive Power theory. Performance of Three-phase Four-wire Shunt Active Power Filter is analyzed here with Proportional and Integral controller and Proportional Integral and Derivative Controller. Simulation is done in MATLAB to verify the results.

This paper presents the design and implementation of three-phase four-wire shunt active power filter (SAPF). It consists of insulated gate bipolar transistors, IGBT based current-controlled voltage source inverter (CC-VSI), series coupling inductor and self-supported DC bus. Power electronics based converters and non-linear loads generate waveform-driven power quality issue as harmonics. Three-phase four-wire SAPF mitigates harmonics, compensates for reactive power, neutral current and power factor correction. Conventionally, the positive sequence detection control strategy using phase-locked loop (PLL) is applied as the synchronizing unit vector element to generate reference source currents. Conventional controller tuning process is difficult and fails to perform satisfactorily under supply voltage variation conditions. In this paper, Levenberg-Marquardt back propagation training algorithm based artificial neural network (ANN) controller is proposed to regulate DC link voltage due to its self-adapting and rapid calculation characteristics that allow the controller to handle high nonlinearity and uncertainty in a non-linear system. Weights of a neuron are adapted to minimize total harmonic distortion (THD) of source current under the step, ramp, time series amplitude variation and frequency and amplitude of modulation conditions. The proposed system is modelled in MATLAB/SIMULINK environment and laboratory prototype with dSpace1104 control card is developed. Experimentation results validate the simulated results of the proposed scheme under supply voltage variations for three-phase four-wire distribution system.

This paper presents three-phase four-wire Shunt Active Power Filters with ability to compensate current harmonics, power factor, and current unbalance. The power stage of the Active Power Filters is based on a two-level four-leg inverter. The switching technique is based on an optimized periodic sampling strategy, and the digital controller uses the Theory of Instantaneous Reactive Power (p-q Theory) expanded for three-phase four-wire systems. The presented Active Power Filters were successfully demonstrated in four different facilities. The presented experimental results show the performance of the Active Power Filters in operation with very different load profiles.

In this paper, the inherent influence of DC-link voltage controller on the steady-state compensation performance in three-phase four-wire shunt active power filter (APF) is investigated. In order to take into account both the DC-link voltage control characteristic and the steady-state compensation performance, an variable parameter DC-link voltage controller is proposed, in which the parameter will be varied according to the difference between the actual and reference DC-link voltage. Representative simulation and experimental results on the three-phase four-wire center-split shunt APF are presented to verify the analysis and also the feasibility and effectiveness of the proposed DC-link voltage controller.

This paper presents a topology based on the interconnection of single-phase H-bridge converters and a three-phase converter acting as a shunt active power filter for three-phase four-wire (3P4W) systems under balanced and unbalanced conditions. Model, PWM approach and control strategies are presented to the studied converter. As compared to the conventional solutions by using just H-bridges converters, the proposed one reduces the number of semiconductor and storage devices. A comprehensive THD analysis will be considered followed by simulated and experimental outcomes.

Active power filters have been used in practice to suppress the harmonic interference in power systems. To compensate for harmonic currents of loads active power filters are usually connected to power systems in parallel with the loads. These filters which are called shunt active filters here are very effective to loads that can be considered as current sources, such a thyristor rectifiers with large DC reactances. Many papers have covered the shunt active filters applied to these currentsource loads. No paper, however, has discussed characteristics of the shunt active filters when they are applied to voltage-source loads.On the other hand, since more and more diode rectifiers with capacitive DC filters are used recently, harmonics generated by which become an issue.The diode rectifier with capacitive DC filters behaves like a voltage source rather than a current source. When a shunt active filter is applied to such a diode rectifier, the current injected from the shunt active filter may flow into the diode rectifier. As a result, harmonics of the source current cannot be reduced effectively, and harmonic current flowing into the diode rectifier increases largely.This paper reveals the above-mentioned problem of shunt active filters analytically and experimentally. Then a series active filter is proposed to suppress harmonic current of the diode rectifiers. The features, operating conditions, and considerations of shunt active filters and series active filters are described analytically and demonstrated experimentally. Taking a diode rectifier with capacitive DC filter as a typical voltage-source load, compensation characteristics of shunt active filters and series active filters are discussed by experiment and simulation. The validity of the series active filters is illustrated experimentally.

A three-phase four-wire shunt active filter (SAF) with photovoltaic (PV) array operated dc–dc converter is proposed in this paper. When the PV system generates excessive or equal power required to the load demand, then the coordinating logic disconnects the service grid from the load and reduces panel tariff. The PV array is connected to the dc side of SAF through the dc–dc converter with fuzzy-based perturb and observe (P&O) maximum power-point tracking (MPPT) algorithm to eliminate the drawback in the conventional PV system. The reference currents extracted by the fuzzy logic controller-based p-q control strategy. This proposed PV-SAF, if connected at the terminals of a small industry or a home, or a small, lighted institution, can avoid the use of an interruptible power supply and individual stabilizer. A MATLAB simulink is presented to validate the advantage of the proposed system.

This paper presents a three-phase four-wire active power filter controlled under an energy approach. For active power filter implementation, a nonconventional converter topology is presented and analyzed. With this topology, and considering harmonics and imbalances in utility voltage and load current, power requirements on the active power filter are studied. From this study, a controller based on the energy state of the system is designed. In this paper, an analytical study and verification by simulation are conducted.

current harmonics, which are injected in the utility by nonlinear loads, cause major problems that tend to deteriorate the power quality at the mains. To reduce such harmonics, active power filters (APF) are commonly employed. In this paper, a new constant-frequency control scheme for a shunt three-phase four-wire APF is proposed. The APF is used to compensate the current distortion and the reactive power created by a typical industrial load. The elaboration of the control law is based on a small-signal averaged model of the converter, computed in the (d,q,0) synchronous frame. The control scheme consists of multiple-loops PI controllers that ensure voltage regulation at the DC side of the filter, and current wave shaping at the AC side. The control system is implemented numerically using Matlab/Simulink tool. The performance of the proposed control approach is finally discussed through the obtained simulation results.

Adaptive non-linear control of three-phase four-wire Shunt active power filters for unbalanced and nonlinear loads.

This paper proposes the application of a combined adaptive controller for the current control loop of a Shunt Active Power Filter (Shunt APF). The proposed approach uses a Variable Structure Controller (VS) together with a Robust Model Reference Adaptive Controller (RMRAC), leading to a VS-RMRAC algorithm. The control law u = ¿ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sup> ¿ is comprised by two set of parameters. One set is related with the RMRAC while the other part is related with the VS controller. The VS parameters are used to improve the transient response, and its effect increases when the estimation error increases. The VS-RMRAC is experimentally tested and compared with a Dead Beat current controller in a three-phase four-wire Shunt APF.

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

FLC based shunt active filter (p–q and Id–Iq) control strategies for mitigation of harmonics with different fuzzy MFs using MATLAB and real-time digital simulator