A High Performance DC/DC Converter as MPPT for Solar Modules

Transcription

1 A High Perfrmance DC/DC Cnerter a MPPT fr Slar Mdule Marjan Dadra*, Meiam Farrkhifar* *Faculty f Electrical Engeerg, Ilamic Azad Unierity Heri Branch, Heri, Iran ([email protected], [email protected]) Crrepndg Authr; Marjan Dadra, Faculty f Electrical Engeerg, Ilamic Azad Unierity Heri Branch, Heri, Iran, Tel: , [email protected] Receied: Accepted: Abtract The energy prduced by lar mdule i fluenced by enirnmental cnditin uch a temperature and radiatin tenity. Therefre, the generated ltage range i ariable. The energy prduced by lar mdule ha the maximum alue at a certa pt. Technique fr Maximum Pwer Pt Trackg (MPPT) applied t tep dwn tep up DC/DC cnerter can be ued t creae the efficiency f lar mdule. In thi paper, a new tep dwntep up DC/DC cnerter i prped which ha lwer ripple at utput ltage and put current cmpared t the cnentinal cnerter. Mreer, the prped cnerter ha fewer number f key and thu le diipatin and greater efficiency cmpared t the cnentinal deice. Keywrd: lar Mdule; Maximum Pwer Pt Trackg (MPPT); tep dwntep up DC/DC cnerter. 1. Intrductin Tday, due t the dicrimate ue f electrical pwer by the peple and dutrie and n the ther hand, cniderg reductin f energy urce and fil fuel uch a il, ga, and cal, there i a particular teret t new and renewable energie uch a wd, lar pwer, and hydrelectric pwer. Mreer, eere pllutin caued by the cnumptin f fil fuel and al endangerg human health and natural life are ther rean caug peple t prefer new and renewable energie. Hweer, the energy prduced by thee Mdule i lw. Therefre, lar mdule are cnnected erie and frm phtltaic mdule which are able t generate a lt f electrical pwer [1]. The effect f temperature change and radiatin tenity n the ltagepwer cure (P) f lar mdule i hwn Fig.1. It can be bered frm the cure P Fig. 1 that an creae temperature can decreae the pwer generated by P mdule at maximum pwer pt. On the ther hand, an creae radiatin tenity can caue an creae the pwer generated the maximum pwer pt f P mdule and the ther functinal pt. Therefre, maximizg the pwer generated by P make it applicatin cteffectie [13]. Therefre, t fd the maximum pt f the pwer generated by P and tranfer it t lad, a DC/DC cnerter huld be applied which i an terface between lad and P mdule and track the maximum pwer pt peratin (MPPT). T perfrm MPPT, Duty rate DC/DC cnerter i changed, and the lad impedance een frm the tw end f P mdule change, accrdgly. Thi will cntue until we reach the maximum pwer pt f P. There are eeral methd t track the maximum pwer pt P, each f which ha it adantage and diadantage. Sme f the methd f maximum pwer pt trackg are Perturbatin and Oberatin (P&O), hill climbg, and cremental cnductance [45]. Thee methd d nt require the frmatin f the P characteritic cure but they hae me cillatin arund the maximum pwer pt, which i a diadantage. We trduce a new P&O algrithm thi paper which reduce thee perturbatin. After electg the deired MPPT methd fr maximum pwer pt f lar panel, the next tep i t elect and deign a new cnerter with high efficiency by which the deired methd can be implemented. 2. Slar Mdule In recent decade, a cmmn mdel fr mathematical exprein f current and utput ltage f lar mdule hae been preented which i al ued t perfrm MPPT. A P array i cmped f a grup f erie and parallel lar mdule t generate the required ltage and current. The equialent circuit fr P array which i frmed by arrangg N p parallel and N erie Mdule i hwn Fig. 2 [6]. The equatin f ltage and current f tw end f P array i btaed frm relatin (1) [2]:

2 Fig. 1. P cure f P mdule fr different temperature (left) and ariu radiatin (right) I N p * I ph N p * I * R N R h N p I * R q N N p * I exp 1 K * TC * A In relatin (1) I ph i phtn current, I i cell aturatin current, q i electrn charge, K i the Bltzmann cntant, T C i the wrkg temperature f the cell, A i an ideal parameter, R h i parallel reitance, and R i lar mdule erie reitance. 3. Maximum Pwer Pt Trackg Algrithm (MPPT) MPPT algrithm f the prped ytem i baed n the direct adjutment f the duty cycle f DC/DC cnerter which i reulted frm the equential cmparin f the utput pwer f lar mdule a well a the difference f utput pwer tw cnecutie mment. Therefre, the prblem f the maximized utput pwer can be led effectiely ug the duty cycle f DC/DC cnerter a a cntrl ariable with Perturbatin and Oberatin (P&O) r the fllwg cntrl law [69]: N p I ph N p N N R / R I N R / R Fig. 2. lar array mdel which i cmped f N p parallel and N erie mdule. h h (1) D k D k1 C 1 P D k1 k1 D k and D k1 are duty cycle alue k and k1 teral, repectiely. P k1 /D k1 are the pwer tilt f P tep k 1, and c 1 i the tep change. The prped Maximum Pwer Pt Trackg baed cntrl algrithm i hwn Fig. 3. In Fig. 3, I, P and are put ltage, put current, put pwer and utput ltage repectiely. The characteritic f the new prped ytem i that P utput pwer i calculated and cmpared with the utput pwer the preiu mment. The reult f the cmparin can help t decide whether the change ign f duty cycle D huld be changed r rema unchanged. 4. The Prped Step dwnstep up DC/DC Cnerter In the prped cnertr which i hwn Fig. 4, bth ltage, higher and lwer than the put ltage, can be achieed the put. In ther wrd, the prped cnertr i a tep dwntep up DC/DC cnerter with cnerin rati f (1D/D). A een Fig. 4, thi cnertr ha three key ( 1, 2, and 3 ), a dide (D 1 ), and tw ductr (L 1 and L 2 ) the put and utput and an energypumpg capacitr (C 1 ) and a capacitr the utput (C 2 ) rder t tabilize utput ltage and reduce the utput ltage ripple. Thi cnerter cmpared t the tep dwntep up Cuk cnerter, with cnerin rati f (D/1D) and ltage with negatie plarity at utput, ha ltage with pitie plarity at utput. Hweer, it ha mre pwer key than thi cnertr. Al the prped cnertr ha a better cnerin rati than the tw tep dwntep up DC/DC cnerter and type KY and hybrid type, becaue thee tw cnertr ha the cnerin rati f 2D. In ther wrd, ug thi cnerin rati, mre than twice the put ltage cannt be prduced at utput (2) 767

3 tart Meaure >max N Meaure,k,I,k Meaure k,ik Pk=k Ik Ye Dk1= P,k= (C 1 ) i charged thrugh the ductr L 1, and ductr L 2, which wa magnetized the preiu mde, i demagnetized thrugh the utput. The prped cnerter thi mde i hwn Fig.5. Circuit equatin thi mde are a fllw: L1 C1 L2 ic 2 il 2 (5) R In the ecnd mde, S 1 key i ff and S 2 and S 3 key are n; bia dide (D) i reere. In thi mde, L 1 i magnetized thrugh the put ltage, and L 2 i charged and magnetized by energy pumpg capacitr (C 1 ), which wa mentined the preiu mde. The prped cnerter thi mde f peratin i hwn Fig. 6. Cnerter tate equatin thi mde are a fllw: (3) (4) Ye Pk>Pk1 Pk> Pk1 N N D i L1 L2 C1 C 2 il 2 R (6) (7) (8) Ye Dk> Dk1 DK1=Dk DK On the ther hand, gien that the aerage ductr ltage L 1 a witchg perid i zer, we hae: T dt L1 1 DT * DT * 1 (1) C (9) Return Fig. 3. the prped Maximum Pwer Pt Trackg Algrithm D D D C * C1 1 D Similarly fr ductr L 2, we hae: (11) (12) L 1 L1 S 2 L 2 S 1 C1 C1 C2 S 3 L2 R T dt L2 1 DT * DT * 1 C (13) (14) Fig. 4. the electrical circuit f the prped tep dwntep up cnerter ltage [1, 11]. Hweer, the prped cnerter preent a ltage rangg frm zer t fity the utput. In the fllwg circuit equatin and the hape f the circuit tw perfrmance mde are tudied. In the firt mde, S 1 key i n and the S 2 and S 3 key are ff and the bia dide i direct. In thi cae, the energy pumpg capacitr D D DC (15) C1 C1 1 * C1 D (16) 768

4 Subtitutg relatin (16) t relatin (12), we hae: 1 D * D 1 D L 1 D (17) (18) L1 L 2 C1 C1 C2 Fig. 5. the electrical circuit f the prped tep dwntep up cnerter when S 1 key i n. L 1 L2 R L1 C 1 L 2 C1 Fig. 6. the electrical circuit f the prped tep dwntep up cnerter when S 2 and S 3 key i n. 5. Simulatin Reult The erall ytem mdel ued the imulatin i hwn Fig. 7. A the figure hw, the ytem cnit f three different part, the firt part clude P mdel ued imulatin, the ecnd part cnit f a tep dwntep up DC/DC cnerter, due t it benefit mentined the trductin, and the third part clude maximizg the generated pwer by P ug MPPT algrithm [112]. Parameter fr bth cnerter are lited table.1. Phtltaic I I MPPT Cntrller DC/DC Cnerter L2 Pule C 2 R Lad In thi ectin, the imulatin reult fr tep dwntep up KY cnerter and fr the prped cnerter and Maximum Pwer Pt Trackg algrithm are cmpared and drew. KY tep dwntep up cnerter ha 2D cnerin rati fr ltage. In ther wrd, mre than twice the put ltage cannt be achieed the utput f the cnerter. Hweer, the prped cnerter ha the cnerin rati f 1D/D and i able t preent utput ltage rangg frm zer t fity. In additin t cnerin rati, tep dwntep up cnerter ripple i an imprtant meaure t ealuate the uefulne f the cnerter. In thi ectin, the ripple f current, ltage, and pwer f the different part f the cnerter are tudied. Table 1. Parameter f cnerter. Parameter Input ductr Output ductr Input capacitance Lad reitance ferequency ize 5 mh 5 mh 1 μf 1 Ω 2 khz Fig. 8 i related t waefrm and utput current ripple f P fr KY tep dwntep up cnerter and Fig. 9 i related t waefrm and utput current ripple f P fr the prped cnerter. Thee tw figure hwed that the prped cnerter ha a lwer ripple alue. Fig. 1 and 11 are related t waefrm, ltage, and utput ltage ripple f P fr KY tep dwntep up cnerter and the prped tep dwntep up cnerter, repectiely. Thee figure dicated that the prped cnerter ha a lwer ripple alue. Accrdg t the figure, the prped cnerter ha a ripple abut.5. Hweer, KY tep dwntep up cnerter ha a ripple abut.4. One f the imprtant parameter affectg the perfrmance reiew f DC/DC cnerter i put current ripple f the cnerter. Waefrm and put current ripple f KY tep dwntep up cnerter and the prped cnerter are hwn Fig. 12 and 13, repectiely. A the figure hw, put current ripple f the prped cnerter i ignificantly le than put current ripple f the hybrid cnerter. Fig. 7. the erall ytem mdel. 769

5 Time() Fig. 8. Waefrm and utput current ripple f P fr KY tep dwntep up cnerter Time() Fig. 9. Waefrm and utput current ripple f P fr the prped tep dwntep up cnerter ltage() Time() Fig. 1. waefrm, ltage, and utput ltage ripple f P fr KY tep dwntep up cnerter ltage() Time() Fig. 11. waefrm, ltage, and utput ltage ripple f P fr the prped tep dwntep up cnerter. 77

6 Time() Fig. 12. Waefrm and put current ripple f KY tep dwntep up cnerter Time() Fig. 13. Waefrm and put current ripple f the prped tep dwntep up cnerter. 6. Cncluin In thi paper, Maximum Pwer Pt Trackg (MPPT) applied t tep dwntep up DC/DC cnerter wa ued t creae the efficiency f lar mdule. Fluctuatin arund the maximum pwer pt, which are the ma diadantage f thi methd, were mewhat reled ug the prped P&O methd. A new tep dwntep up DC/DC cnerter wa prped with lw ripple at utput ltage and put current, cmpared t the cnentinal cnerter. Mreer, the prped cnerter cmpared t the cnentinal cnerter ha fewer number f key and thu le diipatin and greater efficiency. Reference [1] B. Subudhi and R. Pradhan, Characteritic ealuatin and parameter extractin f a lar array baed n experimental analyi, Prc. 9th IEEE Pwer Electrn. Drie Syt, Sgapre, Dec. 5 8, 211. [2] S. Nema, R.K Nema., G. Agnihtri, Matlab/ imulk baed tudy f phtltaic cell/mdule/array and their experimental erificatin, Internatinal Jurnal f Energy and Enirnment, l.1, pp.4875, 21. [3] B. Subudhi, and R. Pradhan, A Cmparatie Study n Maximum Pwer Pt Trackg Technique fr Phtltaic Pwer Sytem, IEEE Tran n Sutaable Energy, l. 4, n. 1, pp , 213. [4] M. Calaia1, J. M. Perié1, J. F. Sanz, and J. Sallán, Cmparin f MPPT trategie fr lar mdule, Prc. Int. Cnf. Renewable Energie Pwer Quality, Granada, Spa, Mar , 21. [5] H. N. Zaud and S. Mekhilef, Cmparin tudy f maximum pwer pt tracker technique fr P ytem, Prc. 14th Int. Middle Eat Pwer Sytem Cnf., Egypt, Dec , 21. [6] N. Femia, G. Petrne, G. Spagnul, andm. itelli, Optimizatin f perturb and bere maximum pwer pt trackg methd, IEEE Tran n Pwer Electrn., l. 2, n. 4, pp , Jul. 25. [7] F. Liu, Y. Kang, Y. Zhang, and S. Duan, Cmparin f p& and hill climbg MPPT methd fr gridcnnected P generatr, Prc. 3rd IEEE Cnf. Indutrial Electrn. Applicatin, Sgapre, Jun. 3 5, 213. [8] S.Maumi Kazraji, S. Khanabdal, R.Bail Sflaye, M. Sabahi A Micr Scale Wd Turbe Fed BLDC Mtr fr Electric Drie ehicle Applicatin Internatinal Jurnal f Renewable Energy Reearch (IJRER), l. 4, n. 1, pp. 3138, 214. [9] H. Abbe, H. Abid, K. Lukil, An Impred Incremental Cnductance Algrithm Ug TS Fuzzy Sytem fr Phtltaic Panel Internatinal Jurnal f Renewable Energy Reearch (IJRER), l. 5, n. 1, pp ,

7 [1] K. I. Hwu, and Y. T. Yau, Tw Type f KY Buck Bt Cnerter, IEEE Tran. Pwer Electrn, l. 56, n. 8, pp , 29. [11] K. I. Hwu, and T. J. Peng, A nel buck bt cnerter cmbg KY and buck cnerter, IEEE Tran. Pwer Electrn, l. 27, n. 5, pp , 214. [12] R.Celh; F.M. Cncer; D.C. Mart, Analytical and experimental analyi f DC DC cnerter phtltaic maximum pwer pt trackg applicatin 36 th Annual Cnference n IEEE Indutrial Electrnic Sciety,