Top PDF Fuzzy Hysteresis Controller Based Unified Power Quality Conditioner for Voltage Fluctuations and Harmonic Isolation

Fuzzy Hysteresis Controller Based Unified Power Quality Conditioner for Voltage Fluctuations and Harmonic Isolation

Fuzzy Hysteresis Controller Based Unified Power Quality Conditioner for Voltage Fluctuations and Harmonic Isolation

Keywords: power quality, voltage fluctuations, harmonics, hysteresis controller, fuzzy controller. I INTRODUCTION Day by day demand of electrical power increasing and power generating stations are far away from the load centers. Therefore very long transmission lines are required. And also different types of loads are used at load centers i.e. balanced and unbalanced loads. Because of the applications of hardware and software for control systems, power quality problems became a challenge for power electronic engineers. Because of advancement in all engineering categories, characteristics of loads have changed completely. Thereby loads are becoming very sensitive to the supplied voltages to them. As we know that power an electronic device draw non-sinusoidal currents from the source and also creates other problems by the rapid switching of power electronic devices. Due to this voltages and currents are disturbed. FACTS devices are making the consumers to satisfy by avoiding these power quality problems. One of the most popular and accurate device which is used for distribution system is Unified Power Quality Conditioner (UPQC). Different operation in compensation can be performed by UPQC according to its controller structure and back-to-back voltage source inverters. This is the operation of UPQC[1].
Show more

7 Read more

A Review on Unified Power Quality Conditioner for 3P4W System

A Review on Unified Power Quality Conditioner for 3P4W System

series active power filter that compensated for source voltage unbalance and current harmonics. In this method, a digital all pass filters and conventional space vector methods are used to generate the reference voltage and current compensation. Shafiee & Machmoum [14] advanced a simplified analogical control of a UPQC. This method deals with a UPQC consisting of a series and parallel active power filtering. An analogical method of perturbation detection for current and voltage parts is presented. To make them totally analogous, the regulators used for different parts of the system were also designed with analogue PID controllers. Carlos et al [15] explored the optimization of a series active filter under unbalanced condition acting in the neutral current. This method considered the limitations of the series active power filter operating in unbalanced 3P4W systems and recommended the insertion of series active impedance to neutral wire. The control of this active impedance uses a modified synchronous reference frame controller in order to mitigate the flow of zero sequence harmonic components. Inoue et al [16] postulated control methods and compensation characteristics of a series active filter for a neutral conductor. The distinct functions of the proposed active filter are the mitigation of the third harmonic voltage and the neutral current in a 3P4W distribution system in a building. The required power of the active filter is less than 10% of that of the harmonic-producing loads. A control method of the DC capacitor voltage on the active filter circuit was also described. Khadkikar & Chandra [17] discussed a method based on the p-q theory. This method presents a direct control strategy of UPQC used in the nonlinear and unbalance 3P4W system. An algorithm of calculating the series compensation current and shunt compensation voltage is introduced. An analysis
Show more

5 Read more

AN EFFICIENT DESIGN OF PI, FUZZY LOGIC BASED IMPROVEMENT OF POWER QUALITY USING UNIFIED POWER QUALITY CONDITIONER

AN EFFICIENT DESIGN OF PI, FUZZY LOGIC BASED IMPROVEMENT OF POWER QUALITY USING UNIFIED POWER QUALITY CONDITIONER

The unified power quality conditioner (UPQC) is a custom power device, which mitigates voltage and current related power quality issues in the power distribution systems. This paper presents a modified UPQC topology with the ANFIS controller on series device (DVR) and PSO tuned PI controller on shunt device (DSTATCOM). The proposed topology also helps to match the DC link voltage requirement of shunt and series device of UPQC. This topology uses a capacitor in series with interfacing inductor of the shunt active filter. The series capacitor enables the reduction in dc-link voltage requirement of shunt device and simultaneously compensating the reactive power required by the load, so as to maintain unity power factor, without compromising its performance. This allows us to match the dc-link voltage requirement of series and shunt device with a common dc-link capacitor. Further in this topology, the system neutral is connected to the negative terminal of the DC-link voltage to avoid the requirement of fourth leg in the voltage source inverter of shunt active filter. The average switching frequency of the switches in the VSI also reduces, consequently the switching losses in the inverter reduces. A simulation study of the proposed topology has been carried out using MATLAB. Detailed comparative studies are made for the modified topology with various controllers.
Show more

6 Read more

A Control Scheme for Dual Unified Power Quality Conditioner to Improve Power Quality

A Control Scheme for Dual Unified Power Quality Conditioner to Improve Power Quality

Fuzzy logic control methodology has been demonstrated to allow solving uncertain and vague problems. In this paper fuzzy logic controller is used for generation of switching pulses for PWM controllers. The advantages of using fuzzy system are simplicity, ease of application, flexibility, speed and ability to deal with imprecision and uncertainties. Due to absorbing and supplying of active and reactive power in active filter, the capacitance voltage is not maintained constant. In literature many controllers are used for capacitance balancing, such as PI, PID, and fuzzy logic controller. In this paper, fuzzy control algorithm is used to balance the dc voltage of capacitance in order to improve the performance of controller. The proposed method is evaluated and tested under non sinusoidal source voltage conditions using Mat lab/Simulink software. The performance of UPQC depends on the characteristic of the active filters. The fuzzy logic controller is used in almost all sectors of industry and power systems and science and one among them is harmonic current and reactive power compensation.
Show more

8 Read more

Neuro Fuzzy Based Unified Power Quality Conditioner for Power Quality Improvement Fed Induction Motor Drive

Neuro Fuzzy Based Unified Power Quality Conditioner for Power Quality Improvement Fed Induction Motor Drive

The unified power quality conditioner (UPQC) plays an important role in the constrained delivery of electrical power from source to an isolated pool of load or from a source to the grid. In this paper presents neuro fuzzy based unified power quality conditioner. The series converter is used to compensate voltage sag/swell compensation. The shunt converter is used to compensate reactive power compensation present in the linear and nonlinear load. The performance of neuro fuzzy and with artificial neural network controller is compared. This approach eliminates the total harmonic distortions efficiently. The performance of proposed system is analysed using Mat lab/Simulink.
Show more

7 Read more

Implementation of Dual Unified Power Quality Conditioner for Power Quality Improvement by Fuzzy Logic Controller
Kolli Tirupati Rao & Anilkumar Alamanda

Implementation of Dual Unified Power Quality Conditioner for Power Quality Improvement by Fuzzy Logic Controller Kolli Tirupati Rao & Anilkumar Alamanda

This concept is called “dualtopology of unified power quality conditioner” (iUPQC),and the control schemes use the p−q theory, for a real time of positive sequence. The aim of this paper is to propose anovel controlled tech- nique for Dual unified Power QualityConditioner for pow- er quality improvement to eliminate the harmonics from source to load. In ABC reference frame, theproposed con- trol scheme is developed for the classicalcontrol theory is without the need for coordinatetransformers and digi- tal control implementation. Thereferences to both SAF and PAF with fuzzy logic controlleris a pure sinusoidal, dispensing the harmonic extraction fromthe grid current and load voltage.A new methodology for the evaluation and control of losses taking place in a UPQC has been proposed.A new control strategy aimed to compensate reactive power, negative sequence current, current har- monics and also to regulate any voltage imbalance has been proposed. A neural network controlled UPQC with- out injection transformer has been designed and reported. Another control structure using linear quadratic regulator (LQR) along with hysteresis control is successfully tested for various operating conditions. UPQC implemented uses a control circuit withoutreference calculation. Com- plicated control structuresof UPQChave been replaced by a simple control technique. Voltage interruption can also beeliminated by the use of a unified power qualitycondi- tioner with distributed generation. Recent research shows that AI based controllers are very promising in the field power system and power electronics. The conventional PI controller is replaced by a fuzzy logic controller [FLC] for the determination of the reference current in a shunt active power filter. The successful application of FLC to generate the switching signals required in an active fil- ter realized using current controlled PWM inverter. T-S fuzzy model is used to predict future harmonic compen- sating current in an APF system.
Show more

11 Read more

Grid Voltage and Current Harmonic Compensation using Fuzzy Logic Based Coordinated Controller

Grid Voltage and Current Harmonic Compensation using Fuzzy Logic Based Coordinated Controller

In this project the compensation of neighborhood load harmonic current utilizing a single DG interfacing converter may make the intensification of supply voltage harmonics delicate burdens, especially when the fundamental grid voltage is very mutilated. Dissimilar to the op generation tion of unified power quality conditioners (UPQC) with arrangement converter, another harmonic current supply voltage and grid current harmonic pay methodology is proposed utilizing facilitated control of two shunt interfacing converters. In particular, the primary converter is in charge of neighborhood load supply voltage harmonicsuppression. The second converter is utilized to alleviate the harmonic current created by the communication between the primary interfacing converter and the nearby nonlinear load. To understand a basic control of parallel converters, an altered mixture voltage and current controller is additionally created in the paper. By utilizing this proposed controller, the grid voltage stage bolted circle and the identification of the heap current and the supply voltage harmonics are pointless for both interfacing converters. In this way, the computational heap of interfacing converters can be fundamentally lessened.
Show more

12 Read more

Enhancing Performance of Fuzzy controlled based New Hybrid Unified Power Quality Conditioner (HUPQC)

Enhancing Performance of Fuzzy controlled based New Hybrid Unified Power Quality Conditioner (HUPQC)

In the proposed controller of DVR, three phase bus bar voltages (vsa, vsb, vsc) are measured and then the “per unit” transform is applied. The magnitude information “A(t)” is determined with the improved SRF based controller for each phase independently by using the per unit values of bus bar voltages and phase angles ș(t) obtained with EPLL. The improved SRF technique can be applied to realize the reference voltage when the unbalanced voltage sag/swell occurs unlike the conventional SRF. In the conventional SRF technique, the three phase voltage signals are used and an average magnitude value is produced as a result of calculated average values of d- and q- components for three phase. For this reason, the conventional SRF technique is not preferred in unbalanced voltage sag/swell conditions. On the other hand, the improved SRF technique produce the magnitude values separately for each phase as follows;
Show more

7 Read more

Power quality enhancement by Unified power Quality Conditioner Using ANN with Hysteresis Control

Power quality enhancement by Unified power Quality Conditioner Using ANN with Hysteresis Control

The power electronic devices due to their inherent non-linearity draw harmonic and reactive power from the supply. In three phase systems, they could also cause unbalance and draw excessive neutral currents. The injected harmonics, reactive power burden, unbalance, and excessive neutral currents cause low system efficiency and poor power factor. In addition to this, the power system is subjected to various transients like voltage sags, swells, flickers etc.[1]-[2] These transients would affect the voltage at distribution levels. Excessive reactive power of loads would increase the generating capacity of generating stations and increase the transmission losses in lines. Hence supply of reactive power at the load ends becomes essential.[3-5].Power Quality (PQ) mainly deals with issues like maintaining a fixed voltage at the Point of Common Coupling (PCC) for various distribution voltage levels irrespective of voltage fluctuations, maintaining near unity power factor power drawn from the supply, blocking of voltage and current unbalance from passing upwards from various distribution levels, reduction of voltage and current harmonics in the system.[6-7].
Show more

7 Read more

Grid Voltage Regulation By Using Pv Based Dual Topology Of The Unified Power Quality Conditioner(Iupqc)

Grid Voltage Regulation By Using Pv Based Dual Topology Of The Unified Power Quality Conditioner(Iupqc)

In an iUPQC the series APF acts as a controlled sinusoidal current supply and the shunt APF acts as a controlled sinusoidal voltage source as shown in Fig.2.The shunt energetic filter offers negligible impedance to the harmonic current, even as the series energetic filter offers an infinite worth. Thus the harmonic present injected through the nonlinear load flows by way of the shunt active filter [6]. The boundaries of traditional UPQC can be overcome by the iUPQC, i.e. In conventional UPQC, whenever the controller has to calculate the compensating voltage and current, for this reason the requirement of processing as well as synthesizing more than one frequency indicators will make the controller design more intricate and has larger switching losses in the converters. The fundamental change between the UPQC and iUPQC is the changes in the shunt and series supply type
Show more

7 Read more

Grid Voltage Regulation by Using PV Based Dual Topology of the Unified Power Quality Conditioner (Iupqc)

Grid Voltage Regulation by Using PV Based Dual Topology of the Unified Power Quality Conditioner (Iupqc)

In an iUPQC the series APF acts as a controlled sinusoidal current supply and the shunt APF acts as a controlled sinusoidal voltage source as shown in Fig.2.The shunt energetic filter offers negligible impedance to the harmonic current, even as the series energetic filter offers an infinite worth. Thus the harmonic present injected through the nonlinear load flows by way of the shunt active filter [6]. The boundaries of traditional UPQC can be overcome by the iUPQC, i.e. In conventional UPQC, whenever the controller has to calculate the compensating voltage and current, for this reason the requirement of processing as well as synthesizing more than one frequency indicators will make the controller design more intricate and has larger switching losses in the converters. The fundamental change between the UPQC and iUPQC is the changes in the shunt and series supply type
Show more

6 Read more

Simulation of Unified Power Quality Conditioner for Power Quality Improvement Using Fuzzy Logic and Neural Networks

Simulation of Unified Power Quality Conditioner for Power Quality Improvement Using Fuzzy Logic and Neural Networks

Keywords: power quality, upqc, voltage sag, fuzzy logic controller, neural networks 1. Introduction Power quality is the set of limits of electrical properties that allows electrical system to function in proper manner without significant loss of performance Like flexible ac transmission system, the term custom power use for distribution system. Just as facts improve the reliability and quality of power transmission system, the custom power enhances the quality and reliability of power that is delivered to customers. The main causes of a poor power quality are harmonic currents, poor power factor, supply voltage variations, etc. In recent years the demand for the quality of electric power has been increased rapidly. Power quality problems have received a great attention nowadays because of their impacts on both utilities and customers. Voltage sag, swell, momentary interruption, under voltages, over voltages, noise and harmonics are the most common power quality disturbances. There are many custom power devices. The devices either connected in shunt or in series or a combination of both. The devices include D-STATCOM, DVR and UPQC etc.One of the most common power quality problems today is voltage dips. A voltage dip is a short time event during which a reduction in R.M.S voltage magnitude occurs. Despite a short duration, a small deviation from the nominal voltage can result in serious disturbances. A voltage dip is caused by a fault in the utility system, a fault within the customer’s facility or a large increase of the load current, like starting a motor or transformer energizing. Unified power quality conditioner (UPQC) is one of the best custom power device used to compensate both source and load side problems. It consists of shunt and series converters connected back to back to a common dc link. It can perform the functions of both DSTATCOM and DVR. In this paper a fuzzy logic controller is used to compensate voltage sag and it is compared with neural network based controller.
Show more

12 Read more

Unit Vector Theory based Unified Power Quality Conditioner for Power Quality Improvement

Unit Vector Theory based Unified Power Quality Conditioner for Power Quality Improvement

In this paper UPQC topology has been proposed with unit vector controlled shunt converterwhich has theability to compensate voltage sagsand current harmonics at the load side. Thus large harmonic problems with non linear loads anddistorted voltage magnitudes are also avoided. In this work a unit vector theory based control algorithm is used for shunt converter and DQ control strategy is used for series converter. The system is tested for three conditions case 1: only sag swells are considered and series compensation is tested and results are presented, case 2: only harmonics are considered and shunt compensation is tested and results are presented, case 3: voltage sag and harmonics are considered and results are presented . Simulation results are clearly show that power quality problems are well mitigated with vector controller based UPQC.
Show more

11 Read more

Fuzzy Based Interline Unified Power Quality Conditioner Using Ten-Switch Topology

Fuzzy Based Interline Unified Power Quality Conditioner Using Ten-Switch Topology

A UPQC generally consists of two voltage source inverters (VSI), connected in shunt and series configuration with the grid, at the point of common coupling (PCC) and share a common dc link capacitor [4]. The series VSI protects the downstream loads from sags/swells in the PCC voltage whereas the shunt VSI reduces the upstream line losses by compensating the harmonic distortion and reactive component of the load current. When the voltage at PCC is distorted, the series VSI can be additionally controlled to mitigate and prevent the voltage harmonics from reaching the load [10]. There
Show more

9 Read more

Comparision Of PI Controller & Fuzzy Logic Controller Using Unified Power Quality Conditioner

Comparision Of PI Controller & Fuzzy Logic Controller Using Unified Power Quality Conditioner

ABSTRACT:Application of power electronic based loads in industry has increased the importance and application of power quality studies. Power electronic equipment’s with nonlinear loads are broadly used in domestic, commercial and industrial applications causing for distortion in current and voltage waveforms. The electronic devices are very sensitive to disturbances and thus the industrial loads become less tolerant to power quality problems like voltage dips, voltage sags, voltage flickers, harmonics and load unbalance, real and reactive power problems etc. In addition to these, the other power quality problems have appeared in the system that reduces the overall efficiency of the system. In this paper, Unified Power Quality Conditioner (UPQC) has been modeled for both active and reactive power compensation using PI and fuzzy control strategy. The behavior of UPQC has been analyzed and the system has been modeled using MATLAB and the results have been compared.
Show more

9 Read more

Fuzzy Based Interline Unified Power Quality Conditioner for Power Quality Enhancement

Fuzzy Based Interline Unified Power Quality Conditioner for Power Quality Enhancement

ABSTRACT: In this paper Fuzzy based Interline Unified Power Quality Conditioner (iUPQC) for power quality enhancement. A Fuzzy Logic Controller (FLC) is based on fuzzy sets and fuzzy rules with their membership functions of inputs and outputs. A control technique of two active filters is to control the sinusoidal reference. In iUPQC; Series Active Filter (SAF) works as a current source and Parallel Active Filter (PAF) works as a voltage source and due to these there is a high and low impedances occurs which is indirectly compensates the harmonics and disturbances of the grid voltage and load current and also impedance path is low harmonic at load current. To deal with sinusoidal reference for well-known frequency spectrum, a technique of pulse width modulation (PWM) is used. A simulation design control, power flow analysis is proposed in interline unified power quality controller (iUPQC) and to eliminate harmonics using a Fuzzy Logic Controller (FLC). In this paper is discussed about structure, control and capability of the iUPQC with Fuzzy Controller technique and efficiency is verified through MATLAB Simulation.
Show more

11 Read more

Unified Power Quality Conditioner for voltage and current compensation

Unified Power Quality Conditioner for voltage and current compensation

system. It consists of combined series and shunt converters for simultaneous compensation of voltage and current imperfections in a point of common connection (PCC) in the distribution side [2]. The series and shunt converters connected back-to-back via a common DC link capacitor. Unlike the UPFC, here the series converter is connected to a supply side and shunt converter is connected load side. This configuration has proved performance with both supply voltage distortions such as sag, swell, harmonics and unbalanced line to line voltages as well as load disturbances such as harmonic current, unbalanced load and reactive power requirement by the load [4],[6]. This configuration also provides optimum rating for a specific amount of sag / swell and reactive power compensation is shown in Fig. 1. The UPQC controller was designed using the instantaneous power method based on αβ0 transform and fundamental positive sequence detection[3].
Show more

6 Read more

Design and Simulation of Dual Unified Power Quality Conditioner with Fuzzy Logic Controller for Power Quality Improvement

Design and Simulation of Dual Unified Power Quality Conditioner with Fuzzy Logic Controller for Power Quality Improvement

As of late, numerous specialists offer regard for tackling power quality issues. These issues are showed up because of use of reactive loads and non-linear loads. This load make reactive power burden and harmonic issue. This harmonic pollution degrades the quality of power at transmission side and distribution side . Typically the term power quality alludes to keeping up a sinusoidal waveform of bus voltages at evaluated voltage and frequency. Electric power quality (EPQ) issues basically incorporate unbalance voltage and current, flicker, harmonics, voltage sag, dip, swell, and power interruption [1], [2]. These power quality issues may bring about unusual operations of offices or even trip protection devices. Consequently, the maintenance and improvement of electric power quality has turned into an imperative situation today. Despite the fact that the power generation is genuinely solid, the quality of power is not generally so reliable. Fuzzy control depends on fuzzy logic; it is much closer in spirit to human deduction and regular dialect than conventional coherent frameworks application to numerous businesses and private utilizations. Henceforth supply of reactive power at the load ends gets to be fundamental [3-5]. Power Quality (PQ) predominantly manages issues like keeping up an fixed voltage at the Point of Common Coupling (PCC) for different distribution voltage levels regardless of voltage fluctuations, keeping up close unity power factor power drawn from the supply, obstructing of voltage and current unbalance from passing upwards from different conveyance levels, lessening of voltage and current sounds in the system [6- 7].
Show more

14 Read more

Enhancing Power Quality of Distributed Power Network with Unified Power Quality Conditioner & FLC

Enhancing Power Quality of Distributed Power Network with Unified Power Quality Conditioner & FLC

ABSTRACT: The growth of electricity demand and the increased number of non-linear loads in power grids, providing a high quality electrical power should be considered. A new component within the flexible AC-transmission system (FACTS) family, called unified power quality conditioner (UPQC) is presented in this paper. The UPQC is derived from the unified power flow controller (UPFC). The unified power quality conditioner (UPQC) is being used as a universal active power conditioning device to mitigate both current and voltage harmonics at a distribution side of power system network. The active power exchange between the shunt and series converters, which is through the common dc link in the UPFC, is now through the transmission lines at the third-harmonic frequency. In this paper, the capability of UPQC with fuzzy logic controllers (FLC) is observed for the power system network. The proposed fuzzy logic controller (FLC) in UPQC is capable of providing good static and dynamic performances. On comparing with and without UPQC, the performance is observed. Application of UPQC with fuzzy logic controller in power quality enhancement is simulated in Matlab/Simulink environment which show the effectiveness of the proposed structure.
Show more

8 Read more

Two Feeder Converter Based Interline Unified Power Quality Conditioner

Two Feeder Converter Based Interline Unified Power Quality Conditioner

lines. Feeder-1 consists of load L-1 which is non-linear and unbalanced. Feeder-2 consists of load L-2which is sensitive. The main purpose of this design is to protect the sensitive load from disturbances occurring upstream and to regulate the voltage at the terminals of Feeder-1. It has been demonstrated that in case of a voltage sag, the VSC connected plays an important role, as it gives the measure of real power required by the load. The IUPQC can mitigate the voltage sag of about 0.33p.u. (i.e. 9kV) in Feeder-2 and 0.6p.u.(i.e. 9kV to 5.5kV) in Feeder-1 for a long duration. The designed IUPQC is capable of handling the system in which the loads are distorted and unbalanced. In an interconnected distribution system, the IUPQC can be used as a versatile device to improve the power quality.
Show more

8 Read more

Show all 10000 documents...