Presentation on theme: "ACTIVE POWER FILTER FOR POWER COMPENSATION"— Presentation transcript:
1ACTIVE POWER FILTER FOR POWER COMPENSATION Presented By:ARUN KUMAR N.K1OX11EPE01
2ABSTRACTIn this Presentation, a new Active Power Filter (APF) control scheme has proposed to improve the performance of the APF. This presentation presents a new technique with instantaneous power theory (P-Q theory) in order to control of APF under non- ideal mains voltage conditions. Performance of the proposed scheme has been found feasible and excellent to that of the instantaneous reactive power algorithms under various non-ideal mains test scenarios. MATLAB/SIMULINK power system toolbox is used to simulate the proposed system. The proposed method’s performance is compared with conventional instantaneous power (P-Q) theory. The simulation results are presented and discussed showing the effectiveness of the control algorithm.
3CONTENTS INTRODUCTION POWER QUALTITY IN POWER DISTRIBUTION SYSTEMS SOLUTIONS TO POWER QUALITY PROBLEMSBASIC PRINCIPLE OF ACTIVE POWER FILTERSTYPES OF THE ACTIVE POWER FILTERSINSTANTANEOUS POWER THEORYTHE PROPOSED METHODSHUNT ACITVE POWER FILTER3-PHASE 4-WIRE SHUNT ACIVE POWER FILTER WITH RENEWABLE ENERGY INTERFACE SIMULATION RESULTSCONCLUSIONREFERENCE
4INTRODUCTIONIn a modern power system, increasing of loads and non-linear equipment's have been demanding the compensation of the disturbances caused for them.These nonlinear loads may cause poor power factor and high degree of harmonics.Active Power Filter (APF) can solve problems of harmonic and reactive power simultaneously.APF have the ability to adjust the amplitude of the synthesized ac voltage of the inverters by means of pulse width modulation or by control of the dc-link voltage, thus drawing either leading or lagging reactive power from the supply.Shunt APF’s allow the compensation of current harmonics and unbalance, together with power factor correction
5POWER QUALITY IN POWER DISTRIBUTION SYSTEM Power Quality can be defined as the physical physical characteristics of the electrical supply provided under normal operating conditions that do not disturb the customers process.Power Quality problem exists due to change in voltage, current or frequency deviation results in a failure or in a bad operation of the equipment.Power Quality problems are due toNatural PhenomenaSwitching PhenomenaConnection of high power non linear loadsVoltage Sags
6SOLUTIONS TO THE POWER QUALTIY There are two approaches to the mitigation of power quality problems.Load ConditioningLine ConditioningA flexible and versatile solution to voltage quality problems is offered by Active Power Filters.Shunt active power filters operate as a controllable current sourceseries active power filters operates as a controllable voltage sourceActive Filter ConnectionLoad on AC SupplyAC Supply On LoadShuntCurrent Harmonic Filtering.Reactive current compensation.Current unbalance.Voltage FlickerSeriesVoltage UnbalanceVoltage Sag/Swell.Voltage Unbalance.Voltage Distortion.Voltage Interruption.Voltage Flicker and notching.
7PRINCIPLE OF ACTIVE POWER FILTER Fig. Block Diagram of APF3phase uncontrolled diode bridge rectifier with resistive loadingUsing the switching mode power converter to perform the harmonic current elimination.The power converter is controlled to generate a compensation current, which is equal but opposite the harmonic and reactive currents generated from the nonlinear load.A voltage source inverter having IGBT switches and an energy storage capacitor on DC bus is implemented as a shunt APF.
8TYPES OF ACITVE POWER FILTERS Shunt Active Power Filters:It compensate current harmonics by injecting equal- but-opposite harmonic compensating current.It operates as a current source injecting the harmonic components generated by the load but phase shifted by 180deg.Fig. Compensation characteristics of a shuntactive power filter
92. Series Active Power Filters: Fig. Series active power filter topologyIt compensate current system distortion caused by non-linear loads.The high impedance imposed by the series APF is created by generating a voltage of the same frequency that the current harmonic component that needs to be eliminated.Voltage unbalance is corrected by compensating the fundamental frequency negative and zero sequence voltage components of the system.
10Hybrid Active Power Filters: Fig. Hybrid Active power filterBy controlling the amplitude of the voltage fundamental component across the coupling transformer, the PF of the power distribution system can be adjusted.The control of the load power factor imposed a higher voltage across the filter capacitor.This type of configuration is very convenient for compensation of high power medium voltage non linear loads
11INSTANTANEOUS POWER THEORY In three-phase circuits, instantaneous currents and voltages are converted to instantaneous space vectors.Three-phase currents and voltages are calculated as following equationsIn three-phase conventional instantaneous power is calculated as follows:P=eα.iα +eβ.iβIn fact, active power (p) is equal to following equation:P=ea.ia +eb.ib +ec.icα and β are orthogonal coordinates.
12Continued…Instantaneous real and imaginer powers are calculated as equationThe above equation can be written asFrom above instantaneous compensating current as α and β Co ordinates are given below
13PROPOSED METHODIt must be used when the voltages are distorted or unbalanced and sinusoidal currents are desired.In proposed method, instantaneous voltages are firs tconverted to α-β coordinates and then to stationary d-q coordinates.The produced d-q components of voltages are filtered and reverse converted α-β coordinates.These filtered α-β components of voltages are used in conventional instantaneous power theory.
18CONCLUSIONA new APF control scheme has been proposed to improve the performance of APF under non-ideal mains voltage scenarios. Experimental results in a scaled-down laboratory prototype will be done and reported in future paper. APF, based on the proposed theory, give satisfactory operation even when the system phase voltages are unsymmetrical and distorted, because no distortion appears in the line currents. The APF is found effective to meet IEEE 519 standard recommendations on harmonics levels in all of the non-ideal voltage conditions. The switching frequency and also switching losses are reduced %23 in proposed method
19REFERENCEEngin Özdemir, Member, IEEE, Murat Kale, Şule Özdemir., “Active Power Filter for Power Compensation Under Non-Ideal Mains Voltages”Luis A. Morán, Juan W. Dixon.,- “Using active power filters to improve power quality”Akagi,H., Kanazawa,Y., and Nabae,A., “Instantaneous reactive power compensators comprising switching devices without energy storage components. IEEE Transactions on Industrial Applications, Vol.20, pp , 1984.Singh, B., Haddad K., Chandra, A., “A New Control Approach to Three- Phase Active Filter for Harmonics and Reactive Power Compensation, IEEE Trans. on Power Systems, Vol.13, No.1, pp , 1998.