PV Based Three-Level NPC Shunt Active Power Filter with Extended Reference Current Generation Method

Transcription

1 nternational Journal of Eletrial Energy, ol. 2, No. 4, Deember 2014 P Baed Three-Level NPC Shunt Ative Power Filter with Extended Referene Current Generation Method M. ijayakumar Department of Eletrial and Eletroni Engeerg, K.S.R College of Engeerg, Tiruhengode , Tamilnadu, ndia mvijaykre@gmail.om S. ijayan Surya Engeerg College, Erode , Tamilnadu, ndia and terferene with eletroni equipment, loe and heatg tranmiion le, vibration and noie motor, malfuntion and failure of meterg/enitive equipment. The everal Cutom power devie have been propoed for enhang the power quality and reliability of eletrial power. nitially, paive filter with tuned LC omponent have been motly ued to uppre harmoni urrent beaue of it low itial ot, imple onfiguration and high effiieny [2], [3]. However, paive filter have many drawbak uh a fixed ompenation, large ize, parallel and erie reonane with load, and utility impedane [4]. All the above mentioned drawbak of paive filter an be overome by ug ative power filter (APF) [5], [6] for the harmoni elimation and reative power ompenation. Ative power filter an be laified a a erie or hunt aordg to their ytem onfiguration. The ombation of erie and hunt ative power filter i alled the unified power-quality ompenator (UPQC). The SAPF i one of the mot important orretive meaure to olve oure urrent harmoni problem [7]. The hunt ative power filter i onneted parallel to the load and it generate the ompenation urrent oppoe to the load harmoni urrent. n reent year, multilevel NPC verter are beomg reagly popular the ative power filter appliation environment. Thi i due to the advantage obtaed from thee topologie, together with the low harmoni ditortion of the voltage and urrent generated, the ize of required filter element are mall, the higher effiieny of the ytem, the low dv/dt, the redued ommon-mode voltage and le eletromagneti terferene [8]. The performane of ative filter topologie maly depend on the referene urrent generation method, e any auray the referene urrent yield to orret ompenation [9]. The variou method have been ued to determe the referene urrent of the SAPF the literature [10], an be ategorized frequeny doma or time doma method. The time doma method require leer omputation ompared to the frequeny doma method. One of the mot ommonly ued method i Abtrat Thi paper propoe an extended referene urrent alulation method for the P baed three-level neutral pot lamped (NPC) hunt ative power filter (SAPF). Shunt ative power filter demand a oure of energy for ompenatg the urrent baed ditortion, whih utilize the photovoltai array with DC-DC boot onverter a a oure of DC power. The hunt onneted verter ontrol the DC lk voltage a well a the ative and reative power tranferred between the renewable energy oure to grid with improved power quality. The propoed ontroller i baed on the ue of high eletivity filter (HSF) for referene urrent generation. n addition the fuzzy logi ontroller i implemented for better urrent ontrol auray of hunt ative filter. The ma benefit of the propoed ytem are that it will provide unterrupted ompenation for the whole day and ompenate the voltage terruption. Thi ytem utilize the renewable energy and aordgly ave the energy, hare the load and provide unterruptable power upply to ritial/enitive load, through the photovoltai (P) array/battery bank durg the day and night. A imulation of the propoed topology ha been arried out the MATLAB/Simulk environment and the reult are preented. Experimental tudie are arried out to onfirm the effetivene of the propoed onfiguration. ndex Term photovoltai ytem, DC-DC power onverter, multi level NPC voltage oure verter, fuzzy ontrol, total harmoni ditortion. NTRODUCTON With the proliferation of power eletroni onverter are ever reag the proeg of eletrial energy dutrial appliation like a adjutable-peed motor drive, eletroni power upplie, diret urrent motor drive, battery harger, et. Thee devie are non-lear load whih draw nonlear urrent from the oure and degraded the power quality the power ditribution network [1]. The evere power quality problem ourred the ditribution feeder are uh a fliker, reonane Manuript reeived May 14, 2014; revied Deember 10, Engeerg and Tehnology Publihg doi: /ijoee

2 nternational Journal of Eletrial Energy, ol. 2, No. 4, Deember 2014 baed on the onventional tantaneou reative power theory or p-q theory [11]. However, the identifiation of the harmoni omponent with the p-q theory maly depend on the quality of the voltage of the eletrial power ytem. The SAPF heme baed on the p-q theory thu need the voltage omponent and thi i onventionally done with a Phae Loked Loop (PLL) ytem [12]. But, thi theory require a number of tranformation. However, thee tranformation, motly onider the eletrial ytem balaned ondition whih i not the real ondition of eletri network. To overome thi problem, the propoed ontrol trategy ued i baed on a modified verion of p-q theory ug two HSF to extrat the fundamental omponent diretly from eletrial ignal (voltage and urrent) α - β referene frame. n thi method, the HSF ha been ued tead of laial harmoni extration baed on high pa filter (HPF) or low pa filter (LPF). After the effiient extration of the referene urrent, an appropriate SAPF urrent ontroller i ued to mata the ative power filter urrent at the impoed referene value [13], [14]. ariou ontrol approahe, uh a the P, PD, lidg-mode ontroller, et., are ued by many author everal work. However, the P ontroller require a peifi lear mathematial model, whih i ompliated to obta and may not give aeptable performane under different ondition uh a parameter variation, unbalaned or ditorted AC voltage, et. The fuzzy logi ontroller have advantage over the P ontroller uh a: it doe not need a preie mathematial model; it an work with impreie put, it an handle nonlearity and it i more robut than the P ontroller [15], [16]. Thi paper extend the ue of the propoed HSF with the SAPF baed on a three-level verter for a three-phae ditribution ytem under the unbalaned ondition. The ma objetive of thi paper are to mata the DC lk voltage of the three level neutral pot lamped parallel onneted verter to provide unterrupted ompenation, utilize the renewable energy, hare the load and provide the unterruptable power upply to ritial/enitive load. The P array i ued to drive the High tep-up DC-DC boot onverter to tep-up the voltage and mata the DC-lk voltage a ontant. The P array i onneted to the boot onverter day time for ontuou ompenation and hare the load to the ditribution ytem. Durg the night time, the battery will at a a DC oure for the boot onverter. Thi power only i ued for ompenation. When the ompenation i not required for the ytem or exe power generated from the P array, it harge the battery. The propoed ytem alo elimate the requirement of UPS and tabilizer for the dividual equipment. n order to ahieve the optimal utilization of P ytem, a low tep-up DC DC onverter aoiated with a funtion alled maximum power pot trakg (MPPT) i trodued between the P array and battery. The imulation and experimental reult are preented to validate the propoed method. Thi paper preent the topology ued and the entire heme of operation of P baed three-level NPC hunt ative power filter with the propoed ontrol heme. The propoed ytem ha been implemented hardware and it reult were preented. Figure 1. P baed neutral pot lamped hunt ative power filter onfiguration. DESGN OF THREE LEEL NPC SHUNT ACTE POWER FLTER The urrent harmoni elimation i ahieved the hunt ative power filter by the jetion of equal but oppoite phae of the harmoni omponent of the nonlear load urrent at the pot of ommon ouplg (PCC), aordgly it make the oure urrent phae with the oure voltage. The propoed P baed hunt ative power filter onfiguration i hown Fig. 1 [10]. For three-level NPC verter, eah leg i ontituted by four ontrollable withe (Sx 1 -Sx 4 ), where x i peified phae (a, b, or ), with two lampg diode. f we onider that two apaitor voltage v DC1 and v DC2 the DC lk are equal, three voltage level (0, v DC /2 and -v DC /2) are generated on the AC termal output of the propoed verter. The 2014 Engeerg and Tehnology Publihg 259

3 nternational Journal of Eletrial Energy, ol. 2, No. 4, Deember 2014 three tate available with a gle leg are hown Table. v fx i the voltage between phae and fitive midpot of the DC lk. The SAPF i onneted parallel with a nonlear load to produe reative and harmoni urrent oppoed to thoe of the nonlear load to anel the harmoni urrent. TABLE. SWTCHNG STATES OF 3 LEEL NPC NERTER C S x x1 S x2 S x3 S x4 v fx v DC / v DC /2 t i aumed that the upper-leg and lower-leg apaitor voltage are idential, with the value v DC /2 eah. n thi ae, the phae-to-midpot voltage of eah phae an be defed: v C v 2 (1) fx x DC where x i the phae dex, x=a, b, ; C x i the tate variable, C x =1, 0, -1 and orrepondg to the threelevel are v DC /2, 0 and v DC /2. Then, the phae-to-neutral voltage of the verter given a: v C C DC b v fa C a 3 v C C DC a v fb C b 3 v C C DC a b v f C 3 The propoed P-SAPF operation ha been divided to three mode of operation. The mode are (i) nverter mode (ii) Compenator mode (iii) UPS mode. i) nverter mode: n thi mode the operation tart workg durg the day time or olar irradiation available. Durg thi period the propoed P-SAPF i utilized to operate a a harmoni and reative power ompenator and hare the ommon load. The exeive power of the P array harge the battery imultaneouly. ii) Compenator mode: When no ative power i gaed from the P array, the ytem i utilized only to ompenate the voltage and urrent baed ditortion and reative power. The battery onneted DC-DC boot onverter manage the DC-lk to provide ontuity of ompenation effetively. iii) UPS mode: Durg the voltage terruption period, the P-SAPF provide the unterruptable power upply to ritial/enitive load, through the P array and battery bank durg day and night time repetively. The grid power upply oure i dionneted through the emiondutor withe (SW), when an oaional power terruption our the omg power upply.. / MODELLNG OF PHOTOOLTAC ARRAY (2) (3) (4) The P array i the whole power generatg unit, ontag a number of olar panel to onvert unlight to eletriity. The development of effiient olar panel with MPPT algorithm have reaed the uage of olar panel a an alternative oure of renewable energy onverion. n the propoed ytem, P array with DC-DC boot onverter joed with a funtion alled MPPT i orporated to work a a DC voltage oure for the hunt verter. The eletrial ytem powered by the P array require DC-DC onverter beaue of the varyg nature of the generated olar powered energy, aued by udden hange weather ondition, whih modify the olar irradiation level along with ell operatg temperature. The equivalent iruit model of photovoltai array with DC-DC boot onverter i hown Fig. 2 [17]. Figure 2. Equivalent iruit model of photovoltai array with DC-DC boot onverter The P array model i developed by the bai equation of photovoltai ell, ludg the effet of temperature hange and olar irradiation level [18]. The output voltage of the P ell i a funtion of photo urrent that i normally determed by load urrent dependg on the olar irradiation level. The P ell output voltage i expreed a AkT ln e ph 0 0 R (5) N P C (6) P (7) N P 19 where, e i the harge the of eletron ( ), i the output voltage of P ell volt, A i urve fittg fator (0.001), Ph i the photo urrent A, 0 i the revere aturation urrent of diode, k i Boltzmann 23 0 ontant ( J / k), T i the operatg temperature of the referene ell (25 0 ), i the ell output urrent Ampere, R i the ell ternal reitane (0.001Ω), pv i the output voltage of P array, P i the output urrent of the P array, N i the number of erie ell and N p i the number of parallel ell. The deign parameter ph, o, R and T are determed from the data heet and - harateriti of the P 2014 Engeerg and Tehnology Publihg 260

4 nternational Journal of Eletrial Energy, ol. 2, No. 4, Deember 2014 array. The urve fittg fator A i ued to adjut - harateriti of the ell to the atual harateriti obtaed by the tetg. The low tep-up DC-DC onverter omprie of a high peed MOSFET with, dutor, diode and apaitor [19], [20]. The output voltage an be ontrolled by varyg the withg duty yle (D) of the with Q 1. When the Q 1 i turned on ug a pule width modulation (PWM) generator, urrent tartg flow through L and Q 1. The energy i tored the dutor (L), the load urrent i upplied by the harge apaitor C. L di L (8) dt (9) L When the with Q 1 i turned off, the dutor voltage add to the oure voltage and urrent due to thi booted voltage now flow from the oure through dutor L, diode and the load, whih reharge the apaitor C. The output voltage out durg T off an be expreed a, di ot u L (10) dt The average output voltage of the onverter i illutrated the equation out 1 D (11) where, D i the duty Cyle, T on i on time, T off i off time and i i the urrent flowg through the dutor L and i the put voltage.. MAXMUM POWER PONT TRACKNG METHOD n the renewable energy ytem the olar power derived from the P array i the ma power oure, and the battery bank erve a the bakup power oure. The renewable energy ytem to provide power for the ompenation and load by P panel a far a poible, and when olar power beome exeive or uffiient, battery power provide the neeary power buffer a a torage or bakup power oure. n pratie, MPPT for the P power ytem i applied to ollet power from the P panel, and a DC-DC boot onverter. n thi paper, the Perturb & Oberve algorithm [21] i hoen for MPPT ontroller implementation, a hown Fig. 3. Figure 3. MPPT ontrol ytem. HGH STEP-UP DC-DC CONERTER n the propoed onfiguration the output voltage level of the low tep-up DC-DC onverter/batterie are low. Aordgly, it i not enough to upply the required DC voltage to the DC lk to ompenate the voltage and urrent baed ditortion and voltage terruption through the parallel onneted voltage oure verter. The high tep up DC-DC onverter i ued to tep-up the low DC voltage to high DC voltage (520). Fig. 4 how the iruit diagram of a high tep up DC-DC onverter [22]. The workg priple of thi onverter i that when the with S i turned on, the oupled dutor due voltage on the eondary ide and magneti dutor L m i harged by put voltage. The dued voltage the eondary make, 1, 2 and 3 to releae energy to the onverter output the erie. When the with S i turned off, the energy tored the magneti dutor L m i releaed via the eondary ide of oupled dutor to harge the apaitor C 2 and C 3 parallel. Figure 4. Ciruit diagram of high tep up DC-DC onverter The propoed onverter operation an be divided to five mode of operation one withg period. The output voltage of high tep-up DC-DC onverter i given a o = + C1 + C2 + L2 + C3 v (13) where, 1, 2 and 3 are the voltage volt aro the apaitor C1, C2 and C3 repetively. v L2 i the voltage aro the eondary of the oupled dutor (N) mode. The voltage aro the apaitor C1, C2, and oupled dutor (N S ) are obtaed a follow: D (1 k) (1 k) n C1 1 D 2 ndk C2 C3 1 D v L2 k (14) (15) (16) where, k i the ouplg oeffiient, n i the oupled dutor turn ratio (N /N p ) and D i the duty yle. The ma role of thi onverter i to mata the ontant voltage aro the DC lk of hunt verter. The imple ontrol truture with P ontroller i implemented for the high tep-up DC-DC onverter to mata the ontant DC lk voltage a hown Fig. 5. The ontrol blok onit of LPF, P ontroller, awtooth wave generator, omparator and relational operator [23], [24]. The output 2014 Engeerg and Tehnology Publihg 261

5 nternational Journal of Eletrial Energy, ol. 2, No. 4, Deember 2014 of the P ontroller give the ontrol ignal required to the relational operator to generate the required duty yle by omparg the proeed error ignal and aw tooth wave. Figure 5.. Controller for high tep up DC-DC onverter PROPOSED CONTROL SCHEME The propoed ontrol truture of the three-level hunt ative power filter omprie of four bai element: To identify the harmoni urrent and form a ynhronized referene, the generation of the gate ignal of the ative power filter, Provide loed-loop ontrol to fore the filter urrent to follow the referene and To regulate the DC apaitor voltage of SAPF to mata the DC voltage at a ontant value. A. Calulation of Referene Current n order to ontrol the SAPF to upply a urrent that i equal to the amplitude and oppoite diretion of the load urrent, a referene urrent wa required. n thi ontrol heme the referene urrent ignal i derived from the meaured quantitie by the utilization of the tantaneou reative power theory aoiated with 2 HSF. The key tep of thi approah are ummarized the implified blok diagram hown Fig. 6. The referene urrent are identified by ug a modified verion of the tantaneou ative and reative power theory. We ued HSF plae of laial harmoni extration baed on HPF or LPF. The HSF i foued on to extrat the fundamental omponent diretly from unbalaned eletrial ignal (voltage or urrent) α - β referene frame. Figure 6. Blok diagram of propoed ontroller Baed on the tantaneou reative power theory, the ytem voltage and the load urrent are tranformed from a-b- oordate to α-β oordate ug the tranformation (17) and (18) [25], [26]: va v 2 vb v v (17) ila i 2 ilb i il (18) The alternatg omponent of the tantaneou real and imagary power are identified by: p vˆ vˆ ih q vˆ vˆ ih (19) A fundamental omponent of the tantaneou imagary power i given a follow q vˆ i vˆ i (20) After addg the ative power required for regulatg DC bu voltage, p, to the alternative omponent of the tantaneou real power, p, the urrent referene the α-β referene frame are alulated: vˆ vˆ i p p q q (21) vˆ vˆ vˆ vˆ vˆ vˆ i p p q q vˆ vˆ vˆ vˆ (22) n order to aquire the referene ompenation urrent a-b- o-ordate, the vere of the tranformation given expreion (17) i ued a follow: i a i b i i i B. dentifiation of the Harmoni Component Ug HSF: (23) The HSF are ued for the harmoni extration tead of laial extration filter uh a a high pa filter or low pa filter. Hong-ok Song [27] had preented that the tegration the ynhronou referene frame i defed by: jt jt xy( t) e e Uxy( t) dt (24) where, Uxy and xy are the tantaneou ignal, repetively before and after tegration the ynhronou referene frame. The equation (24) an be expreed by the followg tranfer funtion, after Laplae tranformation: xy( ) j H( ) Uxy( ) (25) 2014 Engeerg and Tehnology Publihg 262

6 nternational Journal of Eletrial Energy, ol. 2, No. 4, Deember 2014 We trodued a ontant K the tranfer funtion H(), to obta a HSF with a utoff frequeny ω. Therefore, the previou tranfer funtion beome: xy( ) ( K ) j H ( ) K Uxy( ) ( K ) j (26) By replag xy() by Xαβ() and Uxy() by Xˆ () the followg expreion an be obtaed: K ( K ) K Xˆ ( ) X( ) X ( ) ( K ) ( K ), (27) ignifiantly impler the alulation proe and due to their operation at fixed withg frequeny [28], [29]. The withg SPWM pule are generated by ubtratg the filter urrent (i fa, i fb, i f ) with the referene urrent ( ia, ib, i ). The reultg error (e) ( e i if ) i ent to a fuzzy logi ontroller. Then the output ignal of the fuzzy logi ontroller i ompared with a two triangular arrier bipolar ignal hown Fig. 8 [30]. K K ( K ) Xˆ ( ) X ( ) X ( ) ( K ) ( K ) (28) where, X an either be a urrent or a voltage. The equation (27) and (28) an be expreed a follow: ˆ K ˆ X ( ) X ( ) X ( ) X ˆ ( ) (29) ˆ K ˆ X ( ) X ( ) X ( ) X ˆ ( ) (30) Figure 7. Blok diagram of HSF The blok diagram of the HSF how Fig. 7 for extratg the fundamental omponent Xˆ ( ) from the ignal Xαβ () the α-β referene frame. C. SAPF Gatg Signal Generation The performane of SAPF will depend eentially on the type of modulation and adopted urrent ontroller. The everal modulation trategie have been propoed for multilevel onverter three-phae ytem. The modulation tehnique are normally divided to two ma ategorie. The firt tehnique i baed on hyterei omparator, whih i haraterized by a very imple and eay to implement, moreover, it ha the diadvantage of unontrollable withg frequeny. The next tehnique i PWM, whih allow operatg at a fixed withg frequeny, uh a for example uoidal PWM (SPWM) and pae vetor modulation (SM). n thi propoed ytem, the arrier-baed SPWM i ued to generate the appropriate withg ignal of the power withe, e it ha the advantage of makg Figure 8. Fuzzy logi ontroller heme The omparion reult i ent to the ombational logi iruit for the withg devie. Here, the gatg ignal generator ha three put: i f =i i f (orrepondg to i fa, i fb and i f ), the firt arrier-ignal C 1, and the eond arrier-ignal C 2. nitially, we have to determe the termediate ignal T 1, T 2 and T 3 a follow: f if C 1, then T 1 =1, ele T 1 =0; f if C 2, then T 2 =0, ele T 2 =-1; T 3 =T 1 +T 2. After that, we obta the withg funtion of the two withe S x1 and S x2 of the upper leg x (x=a, b, ), the two other leg have withg ignal delayed of 120 ompared to the firt one, and the lower half bridge onta the omplementary withe. D. Propoed Fuzzy Control Sheme The ma purpoe of the AFLC truture i to redue the ontrol heme omplexity and, at the ame time, to keep a high level of the dynami performane and tati of the proe, whoe modelg i ompliated or whoe parameter are aeible. The urrent ontrol loop i reponible for ontrollg the ative power filter urrent the propoed ontrol heme iruit uh that the urrent will try to be the ame a the urrent referene. For thi purpoe, we are tereted to ontrol the ative power filter urrent by a fuzzy ontroller a hown Fig. 9. n our appliation, the fuzzy ontroller ha two put: the differene between the jeted urrent and the referene urrent i error (e) (e=i i f ) and the derivation of the error ( de ) while the output i the ommand (de ). We hooe three fuzzy et for eah of the two put (e, de) with Gauian memberhip funtion, and five fuzzy et for the output with triangular memberhip funtion. For thi, eah lguiti variable (e, de, de) i haraterized by five term of fuzzy ubet: Negative big (NB), Negative (N), zero (ZE), Poitive (P), and Poitive big (PB). The fuzzy ontroller ue the followg five implified rule: 2014 Engeerg and Tehnology Publihg 263

7 nternational Journal of Eletrial Energy, ol. 2, No. 4, Deember f (e) i zero (ZE), then (de) i zero (ZE). 2. f (e) i poitive (P), then (de) i big poitive (BP). 3. f (e) i negative (N), then (de) i big negative (BN). 4. f (e) i zero (ZE) and (de) i poitive (P), then (de) i negative (N). 5. f (e) i zero (ZE) and (de) i negative (N), then (de) i poitive (P). The ferene enge output variable are onverted to the rip value the defuzzifiation tage. ariou defuzzifiation algorithm have been propoed the literature. n thi paper, the entroid defuzzifiation algorithm i ued, whih the rip value i alulated a the entre of gravity of the memberhip funtion 5.. (a) SMULATON RESULTS n thi paper, the propoed ontrol heme baed on a modified verion of p-q theory ug a HSF for the P baed SAPF i evaluated ug Matlab/Simulk oftware under unbalaned and ditorted load-urrent and oure-voltage ondition. n the imulation tudie, the reult are peified before and after the operation of the P baed three-level SAPF ytem. The imulation tudy wa onduted under three different ondition are balaned voltage with balaned load, balaned voltage with unbalaned load and unbalaned voltage with unbalaned load. The omprehenive imulation reult are preented below. (b) () A. Balaned oltage with Balaned Load Fig. 9 Show the imulation reult of load urrent (ilab) before ompenation, ative filter urrent (ifab), oure urrent (iab) after ompenation, verter output le voltage, and oure phae voltage (va) uperimpoed by the oure urrent (ia) of the propoed ytem for the ae of balaned ondition. Fig. 9(e) how the oure urrent (ia) after the ompenation, from thi reult examed that the oure urrent i phae with oure voltage (va) onfirmg that the ompenation i beg done orretly. The harmoni analyi of the oure urrent before and after ompenation phae a are hown Fig. 10(a) and 10(b) repetively. Before ompenation, the meaured total harmoni ditortion (THD) level of the oure urrent phae a wa 25.65%; after ompenation, the THD level of the oure urrent i about 1.54%, whih i well with the limit peified by EEE Std Fig. 11 how the P array output voltage and high tep-up DC-DC onverter output voltage. A ontrol iruit i orporated with the propoed high tep-up DC-DC onverter to regulate the output voltage at 520. The DC-lk voltage, vdc1 and vdc2 mut be mataed almot a a ontant value with erta limit order to provide energy to generate the required harmoni ompenation urrent from the hunt ative filter. Fig. 12 how the diharge harateriti of the battery for variou urrent output. From the harateriti, it i oberved that the bttery an feed 60A for 8 hour duration Engeerg and Tehnology Publihg (d) (e) Figure 9. Simulation reult under balaned voltage with balaned load: (a) load urrent (ilab) (b) oure urrent (iab) () ative filter urrent (ifab) (d) verter output le voltage (e) oure phae voltage (ea) uperimpoed by the oure urrent (ia). (a) 264

8 nternational Journal of Eletrial Energy, ol. 2, No. 4, Deember 2014 (b) Figure 10. THD level of oure urrent (a) THD level of oure urrent before ompenation phae a (b) THD level of oure urrent after ompenation phae a (a) (b) (a) (b) Figure 11. () P array output voltage and high tep-up DC DC onverter output voltage (d) Figure 12. Figure 13. Simulation reult under balaned voltage with unbalaned load: (a) load urrent (ilab) (b) oure urrent (iab) () ative filter urrent (ifab) (d) oure voltage (ea) and oure urrent (ia). Diharge harateriti of the battery for variou output urrent B. Balaned oltage with Unbalaned Load n thi ae, the load urrent are unbalaned by onnetg a gle phae diode retifier onneted between two phae. Fig. 13 Show the imulation reult of load urrent (ilab), oure urrent (iab), ative filter urrent (ifab), and oure voltage (ea) uperimpoed by the oure urrent (ia). THD level of the three phae urrent before tallg the ative power filter are 25.6%, 26.61% and 26.71% repetively. The harmoni petrum of the oure urrent phae a after tallg the ative power filter with modified p-q theory i hown Fig. 14. The THD level ha redued to 2.02%, 1.82% and 1.74% phae a, b and repetively. n addition, the oure urrent i phae with the oure voltage, o that the power fator i equal to one a hown Fig. 13(d) Engeerg and Tehnology Publihg 265 Figure 14. THD level of oure urrent after ompenation of phae a. C. Unbalaned oltage with Unbalaned Load For evaluatg the performane of the SAPF under the unbalaned voltage with unbalaned load, the previou unbalaned non-lear load i fed by unbalaned AC

9 nternational Journal of Eletrial Energy, ol. 2, No. 4, Deember 2014 voltage. The unbalaned oure voltage (eab), unbalaned load urrent (ilab), ative filter urrent (ifab), oure urrent (iab) and oure voltage (ea) uperimpoed by the oure urrent (ia) are depited Fig. 15. The reult hown Fig. 15 onfirm that the P baed SAPF ytem i able to improve the power quality. A hown Fig. 15(), it i evident that three phae oure urrent are balaned and uoidal after ompenation, with power fator loe to the unity, a an be oberved Fig. 16(e). The frequeny analye of the oure urrent after ompenation phae a i hown Fig. 16. The THD of the oure urrent before ompenation are 22.53%, 26.11% and 30.64%; and are redued to 2.12%, 1.86% and 1.82% after ompenation repetively. Simulation reult how that the propoed ontrol trategy ompenate harmoni omponent a well a mot of the other unbalaned load urrent ditortion eletri power ytem with three-phae four-wire. (e) Figure 15. Simulation reult under unbalaned voltage with unbalaned load: (a) unbalaned oure voltage (eab) (b) load urrent (ilab) () ative filter urrent (ifab) (d) oure urrent (iab) (e) oure voltage (ea) and oure urrent (ia). Figure 16. THD level of the oure urrent after ompenation phae a. The THD level of the oure urrent for balaned/unbalaned voltage with unbalaned load ondition i very le about 1.93% the propoed method when ompared with the exitg method whih the THD level are 2.5% and 4.3% a propoed by Abdualam et al 2009 and Mehmet Uar et al 2013 repetively [14], [31]. (a). Thi paper vetigate a new referene urrent generation approah baed on a modified verion of the p-q theory ug a high eletivity filter. Thi approah i propoed the P baed three level SAPF for urrent baed ompenation, reative power and voltage terruption ompenation at reidene or mall dutry. A DC-DC onverter with P&O MPPT algorithm i implemented to trak the maximum power pot of the P array. Additionally, fuzzy logi ontroller i trodued for ontrollg ompenation urrent of the hunt ative power filter. Thi novel P- three level hunt ative power filter i deigned to redue the energy onumption from the utility grid by harg the ommon load, when the P array generate required real power to meet the load demand. The added advantage of the ytem are: redug the panel tariff and avoidg the ue of UPS and power quality onditioner for the dividual equipment at a reidene, mall dutry and eduational titution. The imulation and experimental reult how that, when under balaned, unbalaned and non-lear load ondition, the propoed ontrol heme elimate the impat of ditortion and unbalane of the load urrent on the power ytem. (b) () (d) 2014 Engeerg and Tehnology Publihg CONCLUSONS 266

10 nternational Journal of Eletrial Energy, ol. 2, No. 4, Deember 2014 REFERENCES [1] B. Sgh, et al., A review of three-phae improved power quality AC-DC onverter, EEE Tran. on nd. Eletron., vol. 51, no. 3, pp , Jun [2]. F. Coraaniti, M. B. Barbieri, P. L. Arnera, and M.. alla, Hybrid power filter to enhane power quality a medium-voltage ditribution network, EEE Tran. on nd. Eletron., vol. 56, no. 8, pp , Aug [3] S. Bhattaharya, D. M. Divan, and B. B. Banerjee, Control and redution of termal voltage total harmoni ditortion (THD) a hybrid erie ative and parallel paive filter ytem, Pro. EEE Power Eletron. Spel. Conferene, Jun. 1993, pp [4] F. Z. Peng, Appliation iue of ative power filter, EEE nd. Appl. Mag., vol. 4, no. 5, pp , [5] H. Fujita and H. Akagi, A pratial approah to harmoni ompenation power ytem-erie onnetion of paive and ative filter, EEE Tran. on nd. Appl., vol. 27, no. 6, pp , [6] H. Akagi, Control trategy and ite eletion of a hunt ative filter for dampg of harmoni propagation power ditribution ytem, EEE Tran. on Power Delivery, vol. 12, no. 1, pp , Jan [7] B. Sgh, K. Al-Haddad, and A. Chandra, A review of ative filter for power quality improvement, EEE Tran. nd. Eletron., vol. 46, no. 5, pp , Ot [8] S. Ceballo, J. Pou, E. Roble, J. Zaragoza, and J. L. Mart, Performane evaluation of fault-tolerant neutral pot-lamped onverter, EEE Tran. nd. Eletron., vol. 57, no. 8, pp , Aug [9] K. ardar, E. Akpar, and T. Surgevil, Evaluation of referene urrent extration method for DSP implementation ative power filter, Elet. Power Syt. Re., vol. 79, pp , [10] N. Y. Dai, M. C. Wong, and Y. D. Han, Appliation of a three-level NPC verter a a three-phae four-wire power quality ompenator by generalized 3 DSM, EEE Tran. on Power Eletron., vol. 21, no. 2, pp , Mar [11] H. Akagi, Y. Kanazawa, and A. Nabae, ntantaneou reative power ompenator omprig withg devie without energy torage omponent, EEE Tran. on ndl. Appl., vol. A-20, no. 3, pp , [12] M. A. E. Alali, S. Saadate, Y. A. Chapui, and F. Braun, Advaned orretor with FPGA-baed PLL to improve performane of erie ative filter ompenatg all voltage diturbane, Pro. European Conferene on Power Eletron. and Appl., Aug [13] S. Karimi, P. Poure, and S. Saadate, High performane referene urrent generation for hunt ative filter under ditorted and unbalaned ondition, Pro. EEE Power Eletron. Spel. Conferene, Jun. 2008, pp [14] M. Abdualam, P. Poure, S. Karimi, and S. Saadate, New digital referene urrent generation for hunt ative power filter under ditorted voltage ondition, Elet. Power Syt. Re., vol. 79, pp , [15] A. Hamadi, K. Al-haddad, S. Rahmani, and H. Kanaan, Comparion of fuzzy logi and proportional tegral ontroller of voltage oure ative filter ompenatg urrent harmoni and power fator, Pro. EEE nt. Conferene nd. Tehn., EEE, 2004, vol. 2, pp [16] A. Dellaquila, A. Lei, and. G. Monopoli, Fuzzy ontrolled ative filter driven by an novative urrent referene for ot redution, Pro. EEE nt. Symp. nd. Eletron., 2002, vol. 3, pp [17] M. ijayakumar and S. ijayan, Deign and implementation of P baed three-phae four-wire erie hybrid ative power filter for power quality improvement, ndian Aademy of Siene, vol. 39, no. 4, pp , [18] H. Alta and A. M. Sharaf, A photovoltai array imulation model for MATLAB imulk GU environment, Pro. CCEP, 2007, pp [19] W. Jiang, Y. Zhou and J. Chen, Modelg and imulation of boot onverter CCM and DCM, Pro. EEE Conferene, 2009, pp [20] N. Mazouz and A. Midoun Control of a DC/DC onverter by fuzzy ontroller for a olar pumpg ytem, nt. J Eletr. Power Energy Syt., vol. 33, no. 10, pp , [21] T. Eram and P. L. Chapman, Comparion of photovoltai array maximum power pot trakg tehnique, EEE Tran. Energy Conv., vol. 22, no. 2, pp , Jun [22] Y. P. Hieh, J. F. Chen, T. J. Liang and L. S. Yang, Novel high et-up DC-DC onverter for ditributed generation ytem, EEE Tran. nd. Eletron., vol. 60, no. 4, pp , [23] Y. H. Chang and K. W. Wu, High-Converion-Ratio withed apaitor DC-DC onverter with bidiretional power flow, Pro. Multi Conferene of Engeer and Computer Sientit, 2011, vol. 2. pp [24] M. Abdualam, P. Poure, and S. Saadate, Study and experimental validation of harmoni iolation baed on high eletivity filter for three-phae ative filter, Pro. EEE nt. Symp. nd. Eletron., 2008, pp [25] J. L. Afono, M. J. S. Freita, and J. S. Mart, P-Q theory power omponent alulation, Pro. EEE nt. Symp. nd. Eletron., 2003, vol. 1, pp [26] M. C. Benhabib and S. Saadate, New ontrol approah for four-wire ative power filter baed on the ue of ynhronou referene frame, Elet. Power Syt. Re., vol. 73, pp , [27] H.-S. Song, H.-G. Park, and K. Nam, An tantaneou phae angle detetion algorithm under unbalaned le voltage ondition, Pro. EEE Power Eletron. Spel. Conferene, 1999, vol.1, pp [28] J. Rodriguez, J. S. Lai, and F. Z. Peng, Multilevel verter: A urvey of topologie, ontrol and appliation, EEE Tran. on nd. Eletron., vol. 49, no.4, pp , Aug [29] H. Zhang, S. J. Fney, A. Maoud, and B. W. William, An SM algorithm to balane the apaitor voltage of the three-level NPC ative power filter, EEE Tran. on Power Eletron., vol. 23, no. 6, pp , Nov [30] H. Djeghloud, H. Benalla, and L. Louze, A three-level hunt ative power filter devoted to wd power appliation, Pro. nt. Conferene on Eologi ehile and Renew. Energie, [31] M. Uar and S. Ozdemir, 3-Phae 4-leg unified erie-parallel ative filter ytem with ultraapaitor energy torage for unbalaned voltage ag mitigation, nt. J Eletr. Power Energy Syt., vol. 49, pp , M. ijayakumar reeived B.E. degree Eletrial and Eletroni Engeerg from the Bharathidaan Univerity, Trihy, ndia And he reeived the M.E. degree Power Sytem Engeerg from the Anna Univerity of Tehnology, Coimbatore He i urrently purug Ph.D. degree Eletrial Engeerg, Anna Univerity, Chennai. He i workg a Aoiate profeor at the department of Eletrial and Eletroni Engeerg, K.S.R. College of Engeerg, Tiruhengode , Tamilnadu, ndia. Hi reearh teret are Power quality, FACTS, Harmoni Optimization Tehnique and Grid onneted renewable energy ytem. Dr. S. ijayan reeived the B.E. degree from Madurai Kamaraj Univerity, Tamilnadu, ndia 1989 and the M.E. degree Power Sytem from Annamalai Univerity, Chidambaram He reeived Ph.D. Eletrial Engeerg from Anna Univerity, Chennai He i urrently Profeor and Pripal of Surya Engeerg College, Erode, Tamilnadu. Hi reearh teret lude Power Eletroni and Drive, Renewable energy ytem and power ytem optimization and mart grid Engeerg and Tehnology Publihg 267