Shunt Hybrid Active Filter Research Articles

Adaptive Predictive Deadbeat Current Control of Single-Phase Multi-Tuned Shunt Hybrid Active Power Filters

This paper suggests an adaptive predictive deadbeat current control method for single-phase multi-tuned shunt hybrid active power filters (HAPFs) to improve the power quality of single-phase and three-phase four-wire utility grids. The HAPF structure eliminates the resonance between the passive power filter and the grid impedance. Furthermore, it can be integrated into passive filters to enhance their filtering performance. In this paper, a digital algorithm is proposed for managing the performance of each converter leg accurately. To do so, an exact model of the high-order system is developed, and the transfer function of the plant is calculated in continuous and discrete time domains. Then, a predictive deadbeat technique for HAPF current control is presented, which benefits from high accuracy, fast dynamics, and low sensitivity to system parameter mismatches. Extensive simulation and experimental tests are conducted and the results match well to confirm the success and appropriate performance of the overall system. Also, performance comparison with conventional solutions demonstrates the superiority of the suggested filtering technique.

Parameter design of active damping-based shunt hybrid active power filters

Parameter design of active damping-based shunt hybrid active power filters

Industrial power quality enhancement using fuzzy logic based photovoltaic integrated with three phase shunt hybrid active filter and adaptive controller

Across the globe, solar photovoltaic (PV) sources are treated as the most favorable renewable sources which can fulfill a larger percentage of the total electricity demand with its clean form of energy. But due to its intermittent characteristics, the PV injects lots of uncertainty into the power system. Because of variation in input solar intensity due to climatic conditions, it will impact on the power quality (PQ) issues in power industries. Therefore, in this proposal, a solar PV integrated with shunt hybrid active filter (SHAF) is taken to fulfill the objective of (a) reducing the current harmonics and (b) supplying the active power generated from the PV system. The challenging task in the proposal is to control the PV variables and current control in voltage source inverter (VSI) of the SHAF. Therefore, three-key contributions are made as follows: (a) a control strategy designed which is based on adaptive notch filters (ANF) for reducing the harmonics by generating accurate reference currents; (b) a hysteresis controller is implemented for gating signal pulses; and (c) for maximum power tracking, a fuzzy based maximum power point tracking (MPPT) is developed for the solar tracker. We showed embedded applications of a SHAF for regulating the grid interfaced PV system. Besides a SHAF operated with the ANF and based on the direct current control (DCC) method is used for computing the compensated current. A comparative analysis has been done between ANF (least mean square (LMS) and recursive least square (RLS) method) and the existing non-adaptive notch filters (NNF). Rigorous computer simulations are performed to determine the effectiveness of the proposed system. The real-time digital simulator using OP 5142 designed with low cost and advanced monitoring capability is employed for validating results.

Neural Networks Based Shunt Hybrid Active Power Filter for Harmonic Elimination

The growing use of nonlinear devices is introducing harmonics in power system networks that result in distortion of current and voltage signals causing damage to power distribution systems. Therefore, in power systems, the elimination of harmonics is of great significance. This paper presents an efficient techno-economical approach to suppress harmonics and improve the power factor in power distribution networks using Shunt Hybrid Active Power Filters (SHAPF) based on neural network algorithms like Artificial Neural Network (ANN), Adaptive Neuro-Fuzzy Inference System (ANFIS), and Recurrent Neural Network (RNN). The objective of the proposed algorithms for SHAPF is to enhance system performance by reducing Total Harmonic Distortion (THD). In our filter design approach, we tested and compared conventional pq0 theory and neural networks to detect the harmonics present in the power system. Moreover, for the regulation of DC supply to the inverter of the SHAPF, the conventional PI controller and neural networks-based controllers are used and compared. The applicability of the proposed filter is tested for three different nonlinear load cases. The simulation results show that the neural networks-based filter control techniques satisfy all international standards with minimum current THD, neutral wire current elimination, and small DC voltage fluctuations for voltage regulation current. Furthermore, the three neural network architectures are tested and compared based on accuracy and computational complexity, with RNN outperforming the rest.

Advanced wavelet transform based shunt hybrid active filter in PV integrated power distribution system for power quality enhancement

Power quality (PQ) issues are significant in inverter-fed distributed generation system with non-linear loads which degrades the performance of the consumer equipments and the power system itself. Therefore, this work presents an improved photovoltaic (PV) coupled hybrid filter for the improvement in PQ in an active distribution system. A shunt hybrid active filter (SHAF) integrated with PV is designed with the help of an advanced signal processing approach called dual tree-complex wavelet transform (DT-CWT) for extracting the frequency information in the voltage and current due to the PQ disturbances. For calculating the reference current and switching signals, zero attracting least mean square (ZA-LMS) is considered in the hybrid filter and adaptive perturb and observe-fuzzy algorithm is proposed for maximum power point tracking in PV system to improve the performance under different operating conditions. The system model using the proposed technique is developed in MATLAB/Simulink and real-time experimental set up using two different controllers, i.e. the conventional proportional-integral (PI) and fuzzy-PI controllers. The results on comparison illustrates better performance of the proposed ZA-LMS and DT-CWT with fuzzy-PI based SHAF technique for PQ improvements with respect to that of LMS/normalised LMS with PI/fuzzy-PI based SHAF under different operating scenarios.

Power Quality Improvement in Grid from Wind Turbine by using Shunt Hybrid Active Filter

This paper provides Frame D-Q Synchronous Reference Frame (SRF) current manipulate technique for generating a reference present day that's required for 3-phase four-twine electric hybrid shunt hybrid active power filter (SHAPF) to resolve the hassle of harmonics in the power device community. Here, the passive factors SHAPF has beenused for reactive strength reimbursement and to eliminate the decrease order harmonics and lively parts have been used for the higher harmonics. A modified phase lock loop (PLL) has been used to address multiple frequency elements of non-perfect voltage. All simulations to attain the purpose that has been achieved in the MATLAB / SIMULINK for best conditions and unbalanced electrical voltage. From the simulation results have shown that the implementation of the proposed D-Q SRF SHAPF based THD result in a reduction in community electricity systems in both the balanced and unbalanced situations.

Performance evaluation of multilevel inverter based hybrid active filter using soft computing techniques

In this paper, a multilevel inverter based shunt hybrid active filter is used, which is composed of passive filter and shunt active filter, used for enhancing the quality of power, by reducing the total harmonic distortions below 5% as per IEEE-519 standard and managing the reactive power as well as correcting the power factor. The objective of this paper is to advance the power quality by reducing the harmonic distortions in the distribution line, which are affected because of utilising non-linear loads across the load end. For reference current generation and for controlling the switching signal, conventionally PI controller was used with different reference signal detection techniques. But with the evolution of different intelligence approaches, made more advantageous than the PI controller. In this paper, two artificial intelligence methods, i.e, artificial neural network and adaptive neuro-fuzzy interference system (ANFIS) are applied. Comparison of the results of the proposed methods is analysed using MATLAB/ SIMULINK tool. For reference current generation, synchronous reference frame theory is used and hysteresis current control technique is employed for generating the gating signal.

Design of shunt hybrid active power filter (SHAPF) to reduce harmonics in AC side due to Non-linear loads

<p>The quality of power is a major concern because of harmonics in the lines due to various sources. Passive filters have been used to eliminate the specific harmonics. In this paper shunt hybrid active power filter which consists of shunt active filter and shunt passive filter is designed to reduce harmonics in source side for non linear loads. The shunt passive filter includes a tuned RLC circuit that behaves like a band-pass filter for a particular harmonic content. The shunt active filter is a VSI that produces reverse harmonic current based on Clarke’s transformation. This paper presents the control strategy by implementing instantaneous reactive power theory to design Shunt Hybrid Active Filter (SHAPF) for a non linear load. The proposed control technique is simulated using MATLAB SIMULINK, Results prove there is considerable reduction in THD of source current from 30.35% to 3.25% with the proposed controller on shunt hybrid active power filter. The performance of SHAPF is better than Passive and Shunt Active Power Filters.</p><p> </p>

Real Time Implementation of 3-Phase 4-Wire Shunt Hybrid Active Power Filter Based on PI Controller

Abstract This paper presents an active and reactive (D-Q) current control method to generate the required reference current for three phase four wire shunt hybrid active filter (SHAPF) to solve power system network problems. Here, the passive elements of SHAPF have been used for compensation of reactive power and lower order harmonics and the active part mitigates the higher order harmonics. A modified phase lock loop has been used to handle the double frequency element of non-ideal voltages. A PI controller is used in the DC voltage loop for minimization of unwanted power loss inside the inverter. The simulation has been conducted in MATLAB/SIMULINK environment for ideal and unbalanced mains voltage condition. A laboratory prototype has been built on dSPACE1104 platform to verify the feasibility of the suggested SHAPF controller. From the simulation and experimental results the robustness of the proposed SHAPF controller has been proved.

A Modular Cascaded Multilevel Inverter Based Shunt Hybrid Active Power Filter for Selective Harmonic and Reactive Power Compensation Under Distorted/Unbalanced Grid Voltage Conditions

In recent years, shunt hybrid active power filters are being increasingly considered as a viable alternative to both passive filters and active power filters for compensating harmonics. In literature, their applications are restricted to balanced systems and low voltage applications and therefore not for industrial applications. This paper investigates the performance of a modular cascaded multilevel inverter based Shunt Hybrid Active Power Filter (SHAPF) for reactive power compensation and selective harmonics elimination under distorted/unbalanced grid voltage conditions in medium voltage levels. In the proposed control method, reactive power compensation is achieved successfully with a perceptible amount and the performance results of harmonic compensation are satisfactory. Theoretical analysis and simulation results are obtained from an actual industrial network model in PSCAD. The simulation results are presented for a proposed system in order to demonstrate that the harmonic compensation performance meets the IEEE-519 standard.

Current harmonics compensation with three‐phase four‐wire shunt hybrid active power filter based on modified D – Q theory

This study presents a D–Q current control method with modified phase lock loop to generate the required reference current for shunt hybrid active filter (SHAPF) to improve the power quality. The performance of the proposed controller has been evaluated in terms of harmonic current mitigation and reactive power compensation under different grid conditions. Here, the passive elements of SHAPF have been used for compensation of lower order harmonics and the active part mitigates the higher order harmonics. Proportional–integral controller is considered here for DC-link voltage regulation of the inverter. For verification, the proposed controller of SHAPF is compared with the conventional SHAPF controllers. Extensive simulations of the proposed technique are carried out through MATLAB–SIMULINK environment. A laboratory prototype has been built on dSPACE1104 platform to verify the feasibility of the suggested SHAPF controller. From the simulation and experimental results, the robustness of the proposed SHAPF controller is proved.

T Source Inverter Based Shunt Active Filter with LCL Passive Filter for the 415V 50 Hz Distribution systems

The inverter topology is being used as an active filter to reduce the harmonics in the power system. The traditional voltage source or current source inverters are having the disadvantages of limited output voltage range hence it may not be able to supply enough compensating currents during heavy switching surges, Vulnerable to EMI noise and the devices gets damaged in either open or short circuit conditions and the main switching device of VSI and CSI are not interchangeable. The active filters are the type of DC-AC system with wide range of voltage regulation and integration of energy storages is often required. This cannot be achieved with conventional inverters and hence the impedance source inverters have been suggested. The T source inverters are basically impedance source inverters which can be used as an active filter in the power system. The MATLAB simulation is done and the results are discussed in this paper for both the types. The proposed dampening system is fully characterized by LCL based passive filters and T source inverter based shunt active filter. The disturbances in the supply voltage and load current due to the non linear loads are observed in the simulation. The same is studied after connecting the designed hybrid shunt active filter in the distribution system. The simulation results obtained from the proposed method proves that it gives comparatively better THD value.

PERFORMANCE ANALYSIS OF THREE PHASE SHUNT HYBRID ACTIVE POWER FILTER

Active filtering of electric power has now become a mature technology for harmonic and reactive power Compensation in AC networks. The past several years have seen a rapid increase of power electronics-based loads connected to low and medium voltage power distribution systems. These loads draw non-sinusoidal current from the mains, degrading the power quality by causing harmonic distortion. This paper proposes a three phase Shunt Hybrid Active Filter (SHAF) topology for harmonic reduction and power factor improvement in low voltage power distribution systems. The compensation current reference for the proposed SHAF topology is obtained by using synchronous reference frame theorem. This theorem simplifies the equations for the current reference estimation in d-q co-ordinates thus leading to a more efficient and fast computation. To generate the compensation current that follows the current reference, the hysteresis current control method is adopted for 2-level VSI in low voltage system, the system is verified by developing simulation model using MATLAB/Simulink simulation package and the results are presented. The performance of shunt active filter and the proposed shunt hybrid active filter topology in reducing total harmonic distortion (THD) is compared for low voltage distribution system.

A Lyapunov-Based Control for a Single-Phase Shunt Hybrid Active Filter

In this paper, we analyze the control effect of the Lyapunov control strategy on the single-phase shunt hybrid active power filter based on the averaged state space model. The control law is derived by constructing an appropriate Lyapunov control function, and the switching signals is obtained through the pulse width modulation (PWM). The simulation results show that the Lyapunov-based control for a single-phase shunt hybrid active filter is of stability feature, and has good harmonic compensation performance. It presents better harmonic elimination compared to the the traditional PI and LQR controller.

Simulation of Fuzzy Logic Based Shunt Hybrid Active Filter for Power Quality Improvement

This paper deals with the implementation of fuzzy logic based Shunt Hybrid Active Filter (SHAF) with non-linear load to minimize the source current harmonics and provide reactive power compensation. Comparison with Proportional Integral (PI) based SHAF is also analyzed. Shunt Hybrid Active Filter is constituted by Active Filter connected in shunt and shunt connected three phase single tuned LC filter for 5 th harmonic frequency with rectifier load. The Active Filtering System is based on Synchronous Reference Frame. The proposed fuzzy logic based control strategy improves active filter operation and reduces the selective harmonic contents. The control strategies are demonstrated through MATLAB Simulated Environment.

Parallel-Connected Shunt Hybrid Active Power Filters Operating at Different Switching Frequencies for Improved Performance

This paper proposes a combination of low- and high-frequency hybrid active power filter (APF) to operate in parallel for better performance. The individual hybrid APF is a series combination of L-C filter with the corresponding voltage source inverter. The dc links of both the inverters are connected in parallel, and the voltage of the dc link is maintained by the low-frequency inverter (LFI). The low- and high-frequency inverters eliminate lower order and higher order harmonics, respectively. In addition, it is possible to design the LFI such that it can also compensate the reactive power of the load. The individual L-C filter of the hybrid topology is designed to take care of specific order of harmonics that are predominant in the load. A combination of feedforward and feedback controller is designed for the proposed conditioner. The performances of the proposed topology and the controller are first examined by MATLAB/SIMULINK-based simulation. An experimental prototype is also designed to confirm the usefulness of the proposed system.

A Lyapunov-Function-Based Control for a Three-Phase Shunt Hybrid Active Filter

In this paper, an energy-based Lyapunov function control technique is developed for a three-phase shunt hybrid active filter (SH-AF) to compensate harmonics generated by nonlinear loads and is applied for balanced operation. The method provides compensation for harmonic load current components. The strategy determines the control law that makes the derivative of the Lyapunov function always negative for all values of the states. The dc bus voltage of the SH-AF is maintained to 50 V, which is significantly lower than that of the conventional hybrid active filter. The rating of the active filter in the SH-AF system is much smaller than the one used in the conventional shunt active power filter because the passive filter takes care of the major burden of compensation. The SH-AF performances, during both nominal and severe operating conditions, are then evaluated using a dSPACE DS1104 controller board, supported by a Matlab/Simulink Real-Time Workshop environment. A significantly high correlation between the experimental results and the theoretical model, implemented with Simulink/Matlab, is obtained.

Harmonic suppression in HVDC system using a modified control method for hybrid active DC filter

SUMMARYA shunt hybrid active DC filter (HADF) is applied to eliminate DC transmission line current harmonics in HVDC transmission system. Since the harmonics increase transmission line losses and disturb control and monitoring equipments so HADF are used to suppress harmonics on DC transmission lines. In this paper a modified method is presented to control the shunt HADF which is not dependent on HVDC circuit parameters. HADF by injecting the compensating current to DC transmission line with the modified method suppresses the DC transmission line current harmonics significantly. Six major problems in design of modified control method have been discussed thoroughly. The principle of operation is described and the theoretical analyses are indicated to verify the control strategy. HVDC system is simulated by PSCAD/EMTDC software. Simulation results and comparisons prove and validate the accuracy of these claims. Copyright © 2011 John Wiley & Sons, Ltd.

Hybrid Power Filter to Enhance Power Quality in a Medium-Voltage Distribution Network

This paper deals with the problem of reactive power and harmonics in a standard medium-voltage (MV) distribution network. It proposes a simple and inexpensive solution to enhance power quality when a particular connection to the high-voltage transmission network is required. It presents the design of a hybrid active filter topology connected to the MV level of a power distribution system. Its main task is to regulate a 132-kV voltage level. Reconfiguration of the power delivery network imposes new constraints in a distribution substation so that the reactive compensation should be increased. The topology of a shunt hybrid active filter is analyzed. It is built with the series connection of a passive filter and a low-rated active filter. The proposed filter is directly connected to a 13.8-kV level with no need of a step-down transformer. The possibility of different levels of reactive power compensation is implemented. The proposal shows very good performance for different load demands.

Hybrid Active Filter for Reactive and Harmonics Compensation in a Distribution Network

The problem of reactive power and harmonics in the medium voltage level of a power distribution system is considered in this paper. Reconfiguration of the power delivery network imposes new constraints in a distribution substation so that the reactive compensation should be increased. The alternative of a shunt hybrid active filter connected to the 13.8-kV level to enhance the power quality is analyzed in this paper. This proposal uses the existing capacitor bank to build a hybrid filter in which the complementary compensation is performed by the active filter. The performance of the hybrid filter is evaluated with extensive simulations considering reactive power, harmonics, and unbalance compensation. It shows very good behavior in steady-state and transient conditions.