International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –INTERNATIONAL JOURNAL OF ELECTRICAL ENG...
International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) V...
International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) V...
International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) V...
International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) V...
International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) V...
International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) V...
International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) V...
International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) V...
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Fuzzy controller based current harmonics suppression using shunt active filter

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Fuzzy controller based current harmonics suppression using shunt active filter

  1. 1. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEME & TECHNOLOGY (IJEET)ISSN 0976 – 6545(Print)ISSN 0976 – 6553(Online) IJEETVolume 4, Issue 1, January- February (2013), pp. 162-170© IAEME: www.iaeme.com/ijeet.asp ©IAEMEJournal Impact Factor (2012): 3.2031 (Calculated by GISI)www.jifactor.com FUZZY CONTROLLER BASED CURRENT HARMONICS SUPPRESSION USING SHUNT ACTIVE FILTER WITH PWM TECHNIQUE Dr. Leena G1, Bharti Thakur2, Vinod Kumar3, Aasha Chauhan4 1 (H.O.D, EEE Department, MRIU University, India) 2 (Electrical Department, MRIU University, India) 3 (EEE Department, Al-Falah School of Engineering & Technology, India) 4 (Electrical Department, YMCA University, India) ABSTRACT Harmonics present in the supply as well as at the load sides creates various problems in the smooth operation of devices like variable frequency drives (VFDs), electronic ballasts, battery chargers, and static Var compensators. Active Power Filter (APF) gained much more attention due to good harmonic compensation. The performance of the active power filter depends upon different control strategies. This paper presents detailed analysis about mitigation of harmonics using APF in shunt active mode. The well known control method, instantaneous real active and reactive power method (p-q) method has been utilized in this paper. Extensive Simulations are carried out with fuzzy controller for p-q method for different voltage conditions and adequate results were presented. Simulation results validate the harmonics suppression capability of shunt active power filter under active and reactive power control strategy (p-q) with fuzzy controller. Keywords: Fuzzy Controller, Harmonic Compensation, p-q Control Strategy, Shunt Active Power Filter. 162
  2. 2. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEMEI. INTRODUCTION In recent years, power quality problems and compensation techniques have gained abulk amount of attention. Highly nonlinear electric equipments, in particular, cause severeeconomic loss every year. These days single-phase electronic equipments like computers,communication equipments, electronic lighting ballasts etc have been widely used indomestic, educational and commercial appliances. These devices having different types ofrectifiers to convert AC electricity to DC supply. Hence these instruments utilize non-sinusoidal currents which are a mixture of different harmonics. These current harmonicspollute utility line and also results in many unwanted disturbances in the utility power supplynetwork [1]. Few of these problems can be named as: low power factor, low energyefficiency, electromagnetic interference (EMI), distortion of line voltage etc. Owing to allthese problems, an appropriate harmonics compensator is necessary to avoid theconsequences due to harmonics [2]. One such compensator can be achieved by implementingthe active power filters for power conditioning. it provides functions such as reactive powercompensations, harmonic compensations, harmonic isolation, harmonic damping, harmonictermination. Though for developing these compensators different control strategies have beenproposed by different researchers but still two control strategies, instantaneous active andreactive currents (id-iq) method and instantaneous active and reactive power (p-q) methodshave been always preferred upon others. Present paper is mainly focused on how to reducethe effect of harmonics while using shunt active filters. For extracting reference current ofshunt active filters, control strategy (p-q) has been utilized with fuzzy controller [3]. For thevalidation purpose, extensive simulations are carried out with the above mentionedconfiguration p-q method for sinusoidal voltage conditions and adequate results werepresentedII. CONTROL STRATEGY: INSTANTANEOUS REAL AND REACTIVE POWERMETHOD (P-Q) In this section the Instantaneous Real and Reactive Power (p-q) control strategy,which has been utilized in the present paper, is discussed in detail. Ideal analysis has done insteady state conditions of the active power filter. The p-q theorem is basically a time domainanalysis tool and it has been proven to be especially adequate as one of the active filterscontrol strategies. The notations p and q represents active and reactive powers of the non-linear load. The currents for active power filter are obtained from these active and reactivepowers. Fig. 1 shows the block diagram to attain reference currents from load. The mainobjectives of active power filters [4] are compensations of the harmonics present in the inputcurrents. Present configuration represents three phase four wire and it is realized withconstant power controls strategy [6].Basically, the three phase instantaneous voltages, va, vb,and vc and the load currents iLa, iLb, and iLc, are expressed as instantaneous space vectors theseparameters are transformed into orthogonal coordinates, α-β coordinates using the equations(2.1-2.6). The instantaneous power calculation is given in detail form in equation (2.3). Byderiving from these equations, the compensating reactive power can be identified. Thecompensating current of each phase can be derived by using the inverse orthogonaltransformations as given in the equation (2.5-2.6). It is Important to note that system used isthree phase four wire, so additional neutral currents has to be supplied by the shunt activepower filter. 163
  3. 3. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEME Figure. 1. A basic architecture of three phase four wire shunt active filter V 0  1 / 2 1 / 2 1 / 2  V a      V α = 2 / 3 1 − 1 / 2 − 1 / 2  V b    ( 2 . 1) V β  0 3 / 2 − 3 / 2  V c       I 0  1 / 2 1 / 2 1 / 2   I La      Iα = 2 / 3 1 − 1 / 2 − 1 / 2   I Lb    ( 2 .2 ) I β  0 3 / 2 − 3 / 2   I Lc        p0  V 0 0 0  I 0  p  = 0 V Vβ     ( 2 .3 )    α Iα  q  0 V − Vα  I β     β   The three phase coordinates a-b-c is mutually orthogonal. As a result, the conventional powerfor three phase circuits can be derived by using the above equations. The instantaneous activepower of the three phase circuit, p, can be calculated as shown in equation and theinstantaneous reactive power is defined as follows:- ~ q = ~× i e ~ ~ ~ ~ ~ q = eα × iβ + eβ × iα = eα iβ − eβ iα (2.4) From the instantaneous power can be rewritten as, ICα*   Vα Vβ  − ~ +∆p p  *  =1/ Vα2 +Vβ2    (2.5) ICβ    Vβ −Vα   −q   As the compensator will only compensate the instantaneous reactive power, the real power isalways set to zero. The instantaneous reactive power is set into opposite vectors in order tocancel the reactive component in the line current. From the equation (2.5), yields 164
  4. 4. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEME  ic α *  1 / 2 1 0  − i0         ic β *  = 2/3 1 / 2 − 1/ 2 3 /2   ic α *  ( 2 .6 ) i *     ic β *   cc   1/ 2  − 1/ 2 − 3 /2    By deriving from the equation (2.1) to (2.6), the compensating reactive power can beidentified. The compensating current of each phase can be derived by using the inverseorthogonal transformations. This p-q theorem performs instantaneously as the reactive poweris detected based on the instantaneous voltages and currents of the three phase circuits. Thiswill provide better harmonics compensations as the response of the harmonics detectionphase is in small delay. Figure 2 Conventional Fuzzy Logic ControllerThe actual capacitor voltage is compared with a set reference value. The error signal is thenprocessed through a Fuzzy controller, which provides zero steady error in tracking thereference current signal. In fuzzy logic controller a linguistic control strategy has beenconverted into an automatic control strategy with the use of different fuzzy rules. These fuzzyrules are constructed by expert experience or knowledge data-base available with the system.So the first step of working of fuzzy controller will be comparison of input voltage Vdc andthe input reference voltage Vdc-ref[14]. Then the output variable of the fuzzy logic controlleris followed by the limiter which generates control current Imax . Figure 3. FIS Editor 165
  5. 5. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEME Figure 4 Membership function of input variable Figure. 5 Membership function of output variable Figure. 6 Rule Editor 166
  6. 6. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEME JanuaryIII. SIMULINK MODEL AND SIMULATION RESULTFigure 7. A Simulink model based on reduction of current harmonics using shunt active filter with PWM technique and a PI controller in control unit. Figure.8 Three phase source voltages i.e of phases( a,b,c) Figure.9 3-phase source current with PI controller and THD=32.98% i.e before phase compensation 167
  7. 7. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEMEFigure 8 & 9 clearly shows the waveform of 3-phase source voltage and source currentwith PI controller and it is clear from the waveform that source current has THD=32.98%(i.e before compensation.Figure.10 FFT analysis of input source currents with THD= 32.98% before compensationFigure 11 & 12 clearly shows that the Total Harmnic Distortion in 3-phase source current hasbeen reduced from from 32.8% to 0.13% using PI Controller. Figure.11. 3-phase source current with THD=0.13% with PI controller after compensation Figure.12. FFT analysis of source current after compensation using SAF with PI controller. 168
  8. 8. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEMEFigure.13. 3-phase source current with THD=0.12% after compensation in fuzzy simulink Figure.14 FFT analysis of source current after compensation using fuzzy controllerIV. CONCLUSION The performance of the shunt active power filter is analyzed using PWM with PIcontroller & fuzzy logic for minimizing harmonics, compensating reactive power andimproving the pf in the power system..The SAF theory is used to generate referencecurrent from the distorted load current and maintain the PWM VSI DC side capacitornearly constant.Also Fuzzy logic controller is used to extract the reference current andmaintain the PWM VSI DC side voltage nearly constant. The beauty of this controller is itcan applicable to any system where mathematical models are difficult to get.The performanceof the PWM with PI Controller and shunt active power filter are verified with the simulationresults. Form the results; it clearly indicates that, the current ripple is less in load current ascompared to source current.References[1]. Mikkili Suresh, Anup Kumar Panda, Y. Suresh “Fuzzy Controller Based 3Phase 4WireShunt Active Filter for Mitigation of Current Harmonics with Combined p-q and Id-IqControl Strategies” Energy and Power Engineering, 2011, 3, Published Online February2011(http://www.SciRP.org/journal/epe)[2] Karuppanan P., Mahapatra K.K., “PLL with fuzzy logic controller based shunt activepower filter for harmonic and reactive power compensation” IEEE Conference, IICPT,Power Electronics, (2011):pp.1-6. 169
  9. 9. International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 1, January- February (2013), © IAEME[3] Yacamini R., “Power system harmonics. II. Measurements and calculations” IEEEPower Engineering Journal, vol. 9, (1995): pp. 51-56.[4] Amoli M. E. and Florence T., “ Voltage, current harmonic content of a utility system-Asummary of 1120 test measurements,” IEEE Trans. Power Delivery, vol. 5, (1990):[5] Robert D Henderson, Patrick J. Rose “Harmonics: The effect on power quality andtransformer” IEEE Trans. Industry Applications, vol. 30, no.3, (1994):pp. 528-532.[6] Singh B., Haddad K. A., and Chandra A.,”A review of active power filter for power qualityimprovement”, IEEE Trans. Industrial Electronics, vol.46. no.5, (1999):pp. 960-971.[7] Peng F. Z., Akagi H., Nabae A., “A new approach to harmonic compensation in powersystem- a combined system of shunt passive and series active filters ” IEEETrans. Industry Applications, vol. 26, (1990):pp.983-990.[8] Chen C. and Divan D.M., “Simple topologies for single-phase AC line conditioning” IEEETrans. Industry Applications, vol. 30, (1994):pp. 606–612.[9] Nastran J., Cajhen R., Seliger M., and Jereb P., “Active power filter for nonlinear AC loads,”IEEE Trans. Power Electron., vol. 9, (1994):pp. 92–96.[10] Hafner J., Aredes M. and Heumann K., “A shunt active power filter applied to highvoltage distribution line” IEEE Trans. Power Delivery., vol. 12, (1997): pp. 266–272.[11] Mendalek N., Al-Haddad K., Fnaiech F and Dessaint L.A., “Nonlinear control technique toenhance dynamic performance of a shunt active power filter” IEEE Trans. Power application,vol. 150, (2003):pp. 373–379.[12] Moran S., “A line voltage regulator/conditioner for harmonic-sensitive load isolation,” in Conf.Rec. IEEE IAS Annu. Meeting, (1989):pp. 945–951.[13] Akagi H., Kanazawa Y., and Nabae A., “Instantaneous reactive power compensatorscomprising switching devices without energy storage components,” IEEE Trans. Ind. Applicat., vol. IA-20, (1984):pp. 625–630.[14] Bhattacharya S. and Divan D., “Synchronous frame based controller implementation for ahybrid series active filter system,” IEEE Conf. On Industry applications, vol.4,(1995):pp. 2531–25[15] Lin C. E., Su W. F., Lu S. L, Chen C. L., and Huang C. L., “Operation strategy of hybridharmonic filter in demand-side system,” IEEE-IAS Annul. Meeting, Industryapplications, (1995):pp. 1862–1866.[16] V. S. C. Raviraj and P. C. Sen “Comparative Study of Proportional–Integral, Sliding Mode,and Fuzzy Logic Controllers for Power Converters” IEEE Trans. Industry Applications, Vol.33, (1997):pp. 518-524.[17] C.S Perumalla, P.c Panda, C.S Mishra “Fuzzy controlled Harmonics suppression andreactive volt-ampere compensation for enhancing power quality” World Conference OnNature and Biologically inspired Computing, NABIC 2009; Coimbatore.[18] A. Selwin Mich Priyadharson and Dr. T.R.Rangaswamy, “Cascaded Fuzzy ControllerScheme For Combustion Control of a Utility Boiler Using Control Balance Model”International Journal of Electrical Engineering & Technology (IJEET), Volume 2, Issue 2,2011, pp. 42 - 53, ISSN Print : 0976-6545, ISSN Online: 0976-6553 Published by IAEME.[19] Mr. Laith O. Maheemed and Prof. D.S. Bankar, “Harmonic Mitigation for Non-LinearLoads Using Three-Phase Four Wire UPQC Control Strategy” International Journal ofElectrical Engineering & Technology (IJEET), Volume 3, Issue 1, 2012, pp. 247 - 260, ISSNPrint : 0976-6545, ISSN Online: 0976-6553 Published by IAEME. 170

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