Interntionl Conference on Power nd Energy Systems (ICPS, Dec - 4,, IIT-Mdrs Fryze Power Theory with Adptive-HCC bsed Active Power Line Contioners Kruppnn P, Kml Knt Mhptr, Jeyrmn.K nd Jerlne Viji Abstrct-- This pper presents Fryze power theory bsed threephse, three-wire Active Power Line Contioner (APLC for power qulity enhncement. The shunt APLC system is used for hrmonics nd rective power compenstion due to non-liner lods. The compenstion control strtegy is proposed on ctive nd non-ctive power in the time domin bsed generlized Fryze currents minimiztion theory. PWM-voltge source inverter bsed ctive power filter gte control switching signls re brought out from dptive-hysteresis Current Controller (HCC. This Fryze power theory method mintins the cpcitnce voltge of the inverter constnt without ny dtionl controller circuit. The shunt APLC system is investigted using extensive simultion stues nd the performnce prmeters re obtined under fferent stedy stte nd trnsient contions. A comprtive ssessment of fixed-hcc nd dptive-hcc re crried out. Index Terms-- Fryze power theory, ctive power line contioner, Power qulity, Hrmonics, dptive-hysteresis current controller I. INTRODUCTION Active power line contioners (APLC or ctive power filters (APF hve grown substntilly for solving power qulity problems [-]. In recent yers power qulity effect in industril s well s home utilities hs become mtter of serious concern due to the intensive use of power electronic equipment. Continuing prolifertion of nonliner lods re creting sturbnces like hrmonic pollution nd rective power problems in the power stribution networks [3]. Trtionlly these problems re solved by pssive LC filters. But these pssive filters introduce tuning problems, resonnce, lrge in size nd limited to few hrmonics. So the ctive power-line contioners hs become populr thn pssive filters [4]. It compenstes the current hrmonics nd rective power simultneously. The APLC hs the bility to keep the mins current blnced nd sinusoidl fter compenstion regrdless of whether the lod is liner/non-liner nd blnced or unblnced [3-5]. Kruppnn P, Reserch Scholr, Deprtment of Electronics nd Communiction, Ntionl Institute of Technology, Rourkel, In-7698 (emil: kruppnn98@gmil.com. Kml Knt Mhptr, Professor, Deprtment of Electronics nd Communiction, Ntionl Institute of Technology, Rourkel, In-7698 (emil: kkm@nitrkl.c.in Jeyrmn K, Mnger-Product Development, Industril Controls & Drives (In Pvt.Ltd, Chenni-6 95 Jerlne Viji, Assistnt Professor, Deprtment of Electricl nd Electronics, Milm Engineering College-Tmil Ndu, In-6434 (E-mil: jerldrovn@gmil.com In 93, S. Fryze developed new control method tht fcilittes extrcting the fundmentl component of lod current, commonly known s Fryze power theory. In 979 M. Depenbrock promoted the power nlysis method bsed on the Fryze power theory nd it ws further mofied by F. Buchholz [6-7]. This improved method is now known s FBD (Fryze-Buchholz-Dpenbrock method nd it is used in time domin nlysis [8-9]. In 984, H.Akgi introduced instntneous rective power theory []. In 995, S.Bhttchry proposed synchronous reference frme method for ctive filter []. But these pproches re rther complicted becuse this includes Prk trnsformtion nd p-q or d-q trnsforms. The time domin FBD pproch is n lterntive tht is used to nlyze the reltionship of voltge, current nd rective power clcultion is dopted []. The VSI switching signls re derived from dptive-hysteresis current controller [3-6]. This pper presents generlized Fryze power theory (or Fryze current minimiztion bsed ctive filter for power line contioning. The shunt APLC is implemented with threephse PWM-voltge source inverter nd is connected t PCC for compensting the current hrmonics by injecting equl but opposite hrmonic compensting current. The reference currents re extrcted using Fryze power theory method. The inverter gte drivel signls re derived from dptivehysteresis current controller. This Fryze power method mintins the dc-side cpcitnce voltge of the inverter constnt without ny externl controller circuit. The shunt APLC system is investigted under ode nd thyristor rectifier lod contions. A comprtive ssessment of fixed- HCC nd dptive-hcc re done. II. DESIGN OF SHUNT APLC SYSTEM Active filter for power line contioning system is connected in the stribution network t the PCC through filter inductor nd opertes in closed loop. The shunt APLC system consists of 3-phse inverter, RL-filters, compenstion controller (Fryze power theory controller nd switching signls genertor (dptive-hysteresis current controller s shown in Fig.. The filter inductor provides smoothing nd isoltion for high frequency components. The filter suppresses the hrmonics cused by the switching opertion of the power trnsistors. Control of the current wve shpe is limited by switching frequency of inverter nd by the vilble driving voltge cross the interfcing inductnce. The three phse supply source connected to the non-liner lod (such s ode or thyristor rectifier R-L lod. 978--4577-5-5//$6. IEEE
44 V AC 3-phse, 5 Hz Vbc Lod currents Fryze Power Theory Method i ( t = i ( t i ( t (5 c L s Therefore, the Fryze theory bsed controller of the APLC extrcts the fundmentl component of the lod current tht cn be used for compensting the hrmonics nd rective power simultneously. Non-Liner Lod Ibc is isb isc Fixed-HCC or Adptive- HCC current controller G G G3 Series Inductor Voltge Source Inverter Fig. shunt ctive power line contioners system C DC III. CONTROL STRATEGIES The control strtegies consist of fryze power theory nd dptive-hysteresis current controller. A Fryze Power Theory lgorithm il ilb ilc Active Fryze ( Ge Vs Conductnce Clcultion ( G e Vsb Vsc Low-Pss Filter (LPF ( Ge This nonliner lod current will hve fundmentl nd hrmonic current components, which cn be represented s [5] Active Current Clcultion i, i, i w wb wc Reference Current Clcultion is isb isc i ( t = I sin( nωt+φ L n n n= = Isin( ωt+φ + Insin( nωt+φn n= The instntneous lod power cn be obtined from the source voltge nd current, the clcultion is given s p ( t = i ( t v ( t L s s = Vmsin ωtcosϕ+ VmIsin ωtcos ωtsinϕ + Vmsin ωt Insin( nωt+φn n= = p ( t + p ( t + p ( t f r h This lod power contins fundmentl or rel power p f (t, rective power p r (t nd hrmonics power p h (t. The ctive (fundmentl power drwn by the lod cn be written s p ( t = V I sin ωtcos ϕ = v ( t i ( t (3 f m s s From this eqution, the source current drwn from the mins fter compenstion should be sinusoidl; this is represented s i ( t = p (/ t v ( t = I cosϕ sinωt = I sinωt (4 s f s mx If the ctive power filter provides the totl rective nd hrmonic power, source current i s (t will be in phse with the utility voltge nd would be sinusoidl. At this time, the ctive filter must provide the compenstion current: ( ( Fig. Block grm of generlized Fryze Power Theory method The generlized Fryze power theory method presents minimum rms vlue so tht the sme three phse verge ctive power is drwn from the source s the originl lod current shown in Fig.. This reduces the ohmic losses in the trnsmission line nd gurntees linerity between the supply voltge nd compensted current. The instntneous equivlent conductnce ( G e is clculted from the three phse instntneous ctive power ( p 3φ [6-9] p3 ϕ ( t = vs ( t is ( t + vsb ( t isb ( t + vsc ( t isc ( t = p ( t + p ( t + p ( t s sb sc Moreover the root men squre (rms ggregte voltge is derived from the instntneous vlue of phse voltges, it s given s ( s ( sb ( sc ( V = v t + v t + v t (7 The conductnce or dmittnce ( G e is represented by n verge vlue insted of vrying instntneous vlue. The instntneous conductnce is clculted from the three phse instntneous phse voltges v, vb nd vc clculted from the positive sequence voltge detectorv+ nd lod currents il, ilb nd i Lc. It s derived s [] v i + v i + v i Ge = L b Lb c Lc v + vb + vc (6 (8
The verge conductnce ( G e pss through Butterworth design bsed Low Pss Filter (LPF. The LPF cutoff or smpling frequency is ssigned 5 Hz fundmentl frequency tht llows only the fundmentl signls to the ctive current section. The instntneous ctive currents iw, iwb nd iwc of the lod current re rectly clculted by multiplying ( G e by phse voltges v, v nd v respectively nd re defined s i i i = G v w e = G v wb e b = G v wc e c b c The desired reference source currents clculted from the ctive current, fter compenstion, cn be written s is = iw = Irms sinωt ( i = i = I sin( ωt ( sb wb rms sc wc rms sin( ω i = i = I t+ ( Here i rms is root men squre line current nd the mgnitude is unity. The control strtegy inctes tht shunt APLC should drw the inverse of the non ctive current of the lod nd the results shown compenstes tht currents re proportionl to the corresponng phse voltge. (9 OFF if ictul ( t > iref ( t + H S = ON if ictul ( t < iref ( t H (3 The dvntges of fixed-hcc re simple design nd uncontioned stbility. However, this control scheme exhibits severl unstisfctory fetures such s uneven switching frequency, possible genertion of resonnces. It is lso fficult to design pssive high pss filter system. This unprectble switching function ffects the APF efficiency nd relibility. Adptive-hysteresis current controller overcomes the fixed-hcc demerits. This dptive-hcc chnges the bndwih ccorng to instntneous compenstion current vrition. C Adptive-HCC The dptive-hysteresis current controller is used to generte the voltge source inverter switching signls. The dptive- HCC chnges the hysteresis bndwih bsed on instntneous compenstion current vrition to optimize the required switching frequency. Fig. 4 shows the inverter current nd voltge wves for phse. The current i tends to cross the lower hysteresis bnd t point, where the inverter switch Sis switched ON. The linerly rising current ( i + then touches the upper bnd t point, where the inverter switch S4 is switched ON. The linerly flling current ( i then touches the lower bnd t point 3. B Hysteresis Current Controller The hysteresis current controller is utilized independently for ech phse nd rectly genertes the switching ptterns for the PWM-voltge source inverter. It imposes bng-bng instntneous control method tht drws the APF compenstion current to follow its reference signl within certin bnd limit. i + i - 3 HB i emx Upper Bnd Lower Bnd Actul Current Reference Current +.5Vdc S t S4 t -.5Vdc emin Vdc/ Vdc/ Fig. 3 Hysteresis current controllers This control scheme inflicts on reference current i ref (t to form the upper nd lower limits of hysteresis bnd. The ctul current i ctul (t is compred with i ref (t nd the resulting error is subjected to hysteresis controller to determine the gting signls of the inverter s shown in Fig. 3. The switching performnce is defined s [3] Fig. 4 current nd voltge wves with dptive-hcc The following equtions cn be written in the switching intervls t nd t [4-5] + = (.5 Vdc Vs (4 L = (.5 Vdc + Vs (5 L where L = phse inductnce; ( i + nd ( i re the respective rising nd flling current segments. From the geometry of Fig. 4, we cn write
+ t t = HB (6 t t = HB (7 t + t = T = f (8 c / c Where t nd t re the respective switching intervls, nd fc is the modultion frequency. Adng (6 nd (7 nd substituting (8 we cn write = (9 f + t t c Subtrcting (7 from (6, we get + t t ( t t = 4HB ( Substituting (5 in (, we get R S, L S is Ω nd.5 mh respectively. Filter impednce of R c, L c re Ω nd.3 mh respectively; Diode nd thyristor rectifier R L L L lod re Ω; mh; DC side cpcitnce (C DC is μf; Power devices used re IGBTs with nti prllel odes. Cse Stedy stte This shunt ctive filter system is simulted nd severl importnt prmeters re verified. The wveforms presented re results obtined through hysteresis current controller bsed ctive filter system with thyristor-rectifier R-L lod. This lod genertes six-pulse rectifier wveform. The rectifier lod current or source current before compenstion is shown in Fig. 5 (. This non-liner lod contins fundmentl nd hrmonic components. The shunt ctive filter is connected in the power stribution grid t the PCC for compensting the current hrmonics by injecting equl but opposite hrmonic compensting current. This ctive filter must provide the hrmonic current or compenstion current s shown in Fig. 5 (b. It is cncelling the originl stortion nd improving the power qulity. The source current fter compenstion is presented in Fig. 5 (c tht inctes tht current is sinusoidl. The lod current nd source current re plotted together for comprison purpose in Fig. 5 (d. The results re shown for - phse only; other phses re just phse shifted by + ( t+ t ( t t = 4HB ( Substituting (7 in (, nd simplifying, ( Lod current 6 4 - -4 il / ( t t = ( f ( / c + Substituting ( in (, we compute.5v dc 4L Vs HB = + m fc L V dc L (3 Here, m = / is the slope of reference current signls. The hysteresis bnd HB cn be modulted t fferent points of the fundmentl frequency cycle to control the switching pttern of the inverter. The clculted hysteresis bndwih HB is pplied to the vrible HCC. The vrible hysteresis current control is creted by S-functions in Mtlb to produce gte control signls, which opertes the voltge source inverter for hrmonics nd rective power compenstion. IV. SIMULATION RESULT AND ANALYSIS The performnce of the fryze power theory bsed ctive power filter is evluted through Mtlb using Simulink tools. This system is tested under both stedy stte nd trnsient contion with ode- rectifier nd thyristor-rectifier lods. The system prmeters vlues re; Line to line source voltge is 44 V; System frequency (f is 5 Hz; Source impednce of (b (c Compenstion current Source current (d Lod / Source current -6 5.. time(second.8 ic.4.6.8.4.6 5 5-5 - -5 - time(seconds -5 6.4.6.8...4.6.8 4 - -4-6.4.6.8...4.6.8 Time(seconds 4 - -4-6.4.6.8...4.6.8 time(second Fig. 5 ( Lod current, (b compenstion currents nd (c source current fter compenstion nd (d Lod current compre with source current. Cse Trnsient stte For investigting trnsient behvior, the operting contions re suddenly chnged during the time period T=.6 to.s. In trnsient, the ctive filter system is is il is
simulted for both ode nd thyristor-rectifier lods. However, the wveforms presented re results obtined through dptive HCC bsed ctive filter system with oderectifier R-L lod. The simultion wveform of the threephse c supply voltges re shown in Fig. 6 (. It inctes tht voltges re blnced. The ode-rectifier lod current is shown in Fig. 6 (b tht contins fundmentl nd hrmonic components. The APF supplies the compensting current tht is shown in Fig. 6 (c. The source current fter compenstion is presented in Fig. 6 (d inctes tht currents become sinusoidl fter compenstion. ( (b Supply Voltge n Volts Lod current (c (d Compenstion current in Amp Source Current in Amp 4 3 - - -3 vs vsb vsc -4.6 Stedy Stte. Trnsient Stte. Time(Second.6 Stedy Stte.4.8.4.8 8 6 4 - -4-6 -8 il ilb ilc - 5.6 Stedy Stte. Trnsient Stte. Time(second.6 Stedy Stte.4.8.4.8 4 3 - - -3-4 ic icb icc -5.6 Stedy Stte. Trnsient Stte. Time(seconds.6 Stedy Stte.4.8.4.8 8 6 4 - -4-6 -8 is isb isc -.4.6.8...4.6.8 Time (Seconds Fig. 6 ( supply voltge, (b Lod current, (c compenstion currents nd (d source current fter compenstion current. The fryze power theory controller mintins the DC-side cpcitor voltge constnt without ny dtionl circuit tht shown in Fig. 6 (e. It serves s n energy storge element to supply rel power to operte ctive power inverter. This wveform is for the cse with dptive-hcc bsed ctive filter system with ode-rectifier R-L lod under trnsient contions. Dc-side cpcitor voltge 8 7 6 5 4 3 stedy Stte Trnsient Stte DC-side Voltge stedy Stte..4.6.8...4.6.8 Time(Seconds Fig. 6 (e DC side cpcitor voltges The Fst Fourier Trnsform (FFT is used to extrct the presence of fferent hrmonics long with the fundmentl frequency 5 Hz. The orders of the hrmonics re plotted without nd with ctive power filter. Fig. 7 ( shows the spectrum of ll frequency components with thyristor-rectifier lod contion in stedy stte. Fig. 7 (b shows the spectr of ll frequency components with ode-rectifier lod in trnsient-stte contion. Mgnitude Mgnitude 5 5 5 5 5 Order of Hrmonics with APF Order of Hrmonics without APF ( 4 6 8 4 6 8 Order of Hrmonic Order of Hrmonics with APF Order of Hrmonics without APF 4 6 8 4 6 8 (b Order of Hrmonic Fig. 7 Order of hrmonics ( under thyristor-rectifier with stedy stte nd (b under ode-rectifier with trnsient stte The ctive power nd rective power re clculted by verging the voltge nd current product t the fundmentl frequency. The Fig. 8 is plotted under thyristor-rectifier lod in the stedy stte contion. The ctive nd rective power (P=8.83 kw, Q=. kvar mesured without ctive filter nd with ctive filter (P=8.53 kw, Q=45. VAR. 8 6 4 8 6 4 Rel Power Without APF Rel Power With APF Rective Power Without APF Rective Power With APF -..4.6.8...4.6.8 Fig. 8 Active nd Rective power with or without ctive filter. The Totl Hrmonic Distortion (THD is computed for source current on the c min network. The fryze power theory bsed compenstor filter mkes the source current in the supply line sinusoidl fter compenstion. The totl hrmonic stortion mesured with or without ctive power filter tht re presented in Tble. The Rel (P nd Rective (Q power is clculted nd given in the Tble. This result is mesured under ode-rectifier nd thyristor-rectifier lod contion. This result inctes tht fryze power theory bsed shunt ctive filter is suppressing rective power nd hence improves the power qulity. The FFT nlysis of the APLC system inctes tht the THD of the source current less thn 5 % tht is in complince with IEEE-59 hrmonic stndrds.
Tble Totl hrmonic stortion (THD mesurements Rectifier Lod Contions Without APF With HCC bsed APF With Adptive-HCC bsed APF Diode Stedy stte 4.86 % 4.7 % Trnsient stte 6.8 % 4.79 % 4.63 % Power fctor.9794.9976.9998 Thyristor Stedy stte 3.74 %.77 % Trnsient stte. % 3.86 %. % Power fctor.9669.9977.9998 Tble Rel nd Rective-power mesurements Rectifier Lod Contions Without APF With HCC bsed APF P=.54 kw Q=.6 VAR P=.58 kw Q=7. VAR P=8.53 kw Q=45. VAR P=8.58 kw Q=95.6 VAR With Adptive- HCC bsed APF P=.83 kw Q=48.6 VAR P=.79 kw Q=6.9 VAR P=8.88 kw Q=36.7 VAR P=8.89 kw Q=3.8 VAR Diode Stedy stte Trnsient stte P=. kw Q=54.7 VAR Thyristor Stedy stte Trnsient stte P=8.83 kw Q=. kvar V. CONCLUSION This investigtion demonstrtes tht voltge source inverter bsed shunt ctive power filter fcilittes improving the power qulity. The fryze power theory extrcts the fundmentl or reference components from the storted line currents. The inverter switching signls re derived from dptive-hysteresis current controller. The fryze power theory pproch mintins the DC-side cpcitor voltge of the inverter nerly constnt without ny externl control circuit. The shunt ctive power filter in conjunction with the proposed controller performs perfectly under stedy stte nd trnsient contions. The importnt performnce prmeters re computed under both ode nd thyristor rectifier lods. This fryze power theory pproch brings the THD of the source current to be less thn 5% tht is in complince with IEEE-59 nd IEC 6-3 stndrds. VI. REFERENCES [] Fermin Brrero, Slvdor Mrtinez, Fernndo Yeves nd Pedro M. Mrtinez Active Power Filters for Line Contioning: A Criticl Evlution IEEE Trns on Power Delivery, Vol.5, No., pp.39-35,. [] Kruppnn P nd Kml Knt Mhptr PI, PID nd Fuzzy Logic Controlled Cscded Voltge Source Inverter bsed Active Filter for Power Line Contioners WSEAS Trnsction on Power Systems, Vol.6, No.4, pp.-9, Oct- [3] Joseph S. Subjk. JR nd John S. Mcquilkin Hrmonics- Cuses, Effects, Mesurements nd Anlysis: An Updte IEEE Trns on Industry Appl, Vol.6, No.6, pp.34-4, 99. [4] Bhim Singh, Kml Al-Hddd & Ambrish Chndr A Review of Active Filter for Power Qulity Improvements IEEE Trns on Industril Electronics, Vol.46, No.5,.96-97, 999. [5] Shilendr Kumr Jin, Prmod Agrwl nd H. O. Gupt A Control Algorithm for Compenstion of Customer-Generted Hrmonics nd Rective Power IEEE Trns on Power Delivery, Vol.9, No., pp.357-366, 4. [6] U. Hpenbrock The FBD method generlly pplicble tool for nlyzing power reltions IEEE Trnsctions on Power Systems, Vol. 8, No.. My-993 [7] M. Depenbrock nd V.Stu The FBD-Method s Tool for Compensting Totl Non-Active Currents Interntionl Conference on Hrmonics nd Qulity of Power ICHQ, pp.3-34, 998. [8] Luis F.C. Monteiro, Muricio Aredes nd Joo A. Moor Neto A Control Strtegy for Unified Power Qulity Contioner IEEE conference, pp.39-396, 3. [9] Kruppnn nd KmlKnt Mhptr A Control Strtegy for Shunt Active Power Line Contioners Ntionl Conference on Power Electronics (NPEC,. [] Hirofimi Akgi, Yoshihir Knzw nd Akir Nbe Instntneous Rective Power Compenstors Comprising Switching Devices without Energy Storge Components. IEEE Trns on Industril Appl, Vol.I-, No.3, pp.65-63, 984. [] Subhshish Bhttchry Deepk Divn synchronous reference frme bsed controller for hybrid series ctive filter system Industry Applictions Conference, IAS Annul Meeting, pp.53-53, 995. [] Hirofumi Akgi, Edson hirokzu wtnbe nd Muricio Aredes Instntneius power theory nd pplictions to power contioning IEEE-press chpter 3-4, 7. [3] Jing Zeng, Chng Yu, Qingru Qi, Zheng Yn, Yixin Ni, B.L. Zhng, Shousun Chen nd Felix F. Wu A novel hysteresis current control for ctive power filter with constnt frequency. Electric Power Systems Reserch 68, pp.75-8, 4. [4] Biml K Bose An Adptive Hysteresis-Bnd Current Control Technique of Voltge-Fed PWM Inverter for Mchine Drive System IEEE Trns on Industril Electronics, Vol.3, No.5, pp.4-48, 99. [5] Murt Kle nd Engin Ozdemir An dptive hysteresis bnd current controller for shunt ctive power filter Electric Power Systems Reserch 73, pp.3 9, 5 [6] Kruppnn P nd Kmlknt Mhptr A Novel PLL with Fuzzy Logic Controller bsed Shunt Active Power Filter for Hrmonic nd Rective power Compenstion IEEE In Interntionl Conference on Power Electronics (IICPE, Feb-.