Design and simulation of shortcut current MPPTracking technique to control boost converter

Transcription

1 Revue de Energie Renouvelable Vol. 21 N 1 (2018) Deign and imulation of hortcut current MPPTracking technique to control boot converter H. Serghine *, R. Chenni and K. Nebti Laboratoire d'electronique, Univerité de Frère Mentouri Contantine 1, B.P. 325 Route de Ain El Bey, Contantine, Algérie (reçu le 24 Mar accepté le 30 Mar 2018) Abtract - Thi paper preent the control of boot converter uing MPPT technique in photovoltaic ytem. The hort circuit current technique i characterized by it implicity and eaily realized. The technique i baed on the meaure of the hort circuit current of panel conidered a a reference, and the comparion with the real current i helpful to create the control pule of the DC/DC converter. We realize the Boot converter uing GBT 'RGPC60' tranitor protected by RCD (Reitance, Capacitor and Diode) circuit. The galvanic iolation i achieved by photo coupler CNY18. Experimental reult are meaured uing Dpace interface board to verify the validity of the preented technique. Réumé - Cet article préente le contrôle du convertieur boot en utiliant le technique MPPT dan un ytème photovoltaïque. La technique du courant de courtcircuit e caractérie par a implicité et a réaliation aiée. La technique et baée ur la meure du courant de court-circuit conidéré comme référence, et la comparaion avec le courant réel et utile pour créer l'impulion de commande du convertieur DC / DC. Nou réalion le convertieur Boot en utiliant le tranitor GBT 'RGPC60K' protégé par le circuit RCD (Réitance, Condenateur et Diode). L'iolation galvanique et réaliée par photo coupleur CNY18. Le réultat expérimentaux ont meuré en utiliant la carte d'interface Dpace pour vérifier la validité de la technique préentée. Keyword: Short circuit current - MPPT - Boot converter - PV ytem - Dpace interface. 1. NTRODUCTON The demand for electric energy ha been increaing in lat year a well a the contraint linked to it production, uch a the effect of pollution and global reheating, lead reearch toward the development of renewable energy ource [6]. Among thee photovoltaic energy which i currently a trong development in the word. Thi development i booted by international and national policie aimed at reducing the ue of foil energy. The maximum output power of PV module depend on temperature, olar inolation and load, o it i neceary to track MPP of PV array all the time for deferent' technique. The mot ued technique diturb and oberve (P&O) method, in the firt cae; thi mean that the reference change in the poitive direction, and the continuou tep of voltage to be added to the reference with the ame ign. n the econd, the algorithm evolve in the negative direction, and the tep i changed ign to regain increaing power. Thi method ued widely due to it implicity and efficiency, however there i eriou power ocillation around MPP which decreae the efficiency of PV ytem [8]. To reduce the power ocillation, perturbation tep hould be adjuted according to work point of PV module [9]. * Haiba-erghine@outlook.com - idor2003@yahoo.fr rachidchenni@yahoo.fr 37

2 38 H. Serghine et al. Thi lat ha been largely ued becaue it i eay to implement, it i baed on the perturbation incrementing or decrementing the voltage V ref, or the current ref with oberving the reult of thi diturbance on the meaured power. The econd algorithm i the "Hill-Climbing". According to the ame principle, it i thi time directly the cyclic ratio of the chopper controlling the panel i incremented or decremented. After a reminder about the different method ued to find the maximum power point of a photovoltaic generator, we will preent the objective of thi work. Thi work conit of the verification by imulation of hort circuit current fraction control technique (FSCC) and alo validate thi algorithm by experimental reult. The deign of any PV ytem depend mainly on pecific parameter uch a olar irradiance, number of unhine hour and the temperature variation [1] 2. MODELNG OF PV SYSTEM Fig. 1: Equivalent circuit of PV olar cell The voltage i uceptible to change depending on the temperature. Reheating of the module how a decreae in voltage. Thi i why it important to ventilate the module o that they do not loe too much voltage. When the variation of the voltage i due to the temperature i unavoidable, o the number of panel in erie can be changed in order to compenate voltage drop. According to the law of Kirchhoff: ph d (1), i the harveted current of the cell. ph, i the olar-generated current. [4]. The harveted current ph, depend on the olar irradiance linearly and it i given by ph ph (T ) (1 K (T T )) (2) ph 1 cc 1 0 K (T ) (T ) (G/G ) (3) (T ) (T ) T (4) 0 cc 2 cc 1 2 T1 K 0, i the hort circuit current / temperature coefficient. T, i the temperature of the cell. T 1, the temperature of the cell and the nominal cell temperature ( T 1 = 25 C = 298 K). G 0, the reference irradiance ( G n = 1000 W/m 2 ). cc, hort circuit current {the current that circulate through the junction under illumination when the cell i in hortcircuit). From the equation (2) the PV junction current intenity change according to the illumination. The more light i trong, the intenity i higher. ndeed, it i the photon of light that tranmit their energy to the electron and releae them during the day. At

3 Deign and imulation of hortcut current MPPTracking technique to control boot noon, when the irradiance i at maximum, the production of cell increae to the maximum. The ideal condition for the operation of a cell are the maximum irradiation at a minimum temperature., Current croing to the diode, it given by: d d (V V ) d T e 1 (5) V T, Thermodynamic voltage defined by: V T nkt/q (6) n, i the ideality factor of the diode. K, i the Boltzmann contant. acro the diode. V d V d, Voltage V R (7) V, i the harveted voltage of the cell. R X v d V d 1 X Voc V R, i the erie reitance. (8) Voc(T1 ) VT ( T1 (T ) V (T ) e 1 T 1 (9) V oc, The open circuit voltage {meaured voltage when current don't circulate in the photovoltaic device}., i the aturation current of the diode and it i defined by: 3/ n ( qvg / n (1/T 1/T ) k) 1 (T1 ) (T / T1 ) e Voc(T1 ) VT (T1 ) ) (T ) / e 1 (10) (T 1 (11) cc 1 The harveted current from the cell i given by [3] ph e ( qv / nk) g PV panel validation We choe the photovoltaic model TE 600, which contain 36 erie cell ( n _ 36). Table 1: Electrical pecification of the olar module Maximum power, m 60 W Voltage at maximum power, V mp 17.6 V Current at maximum power, mp 3.47 A Short circuit current, cc 3.65 A Open circuit voltage, V oc 22.0 V Temperature coefficient, K ±0.015)%/ C (12)

4 40 H. Serghine et al. Fig. 2: MPP determination Zone (): the current remain contant whatever the voltage, in thi area, the photovoltaic generator function a a current generator. Zone (): correponding of the curve of the characteritic, the intermediate region between the two zone ( and ), repreent the preferred region for the operation of the generator, where the optimal point (characterized by maximum power) can be determined. Zone (): which i characterized by a current variation correponding to a nearly contant voltage, in thi cae the generator i comparable to a voltage generator. 2.2 Temperature influent Fig. 3: Temperature influence on PV panel Decreaing the temperature caue the decreae of the erie reitance, which reduce the voltage drop and increae the current. 2.3 rradiation influent Fig. 4: rradiation influence on PV panel The current i directly proportional to the irradiation at thee level of illumination {Eq. (3)}, which jutifie the increae of the current when the illumination increae. 2.4 Panel aociation

5 Deign and imulation of hortcut current MPPTracking technique to control boot Fig. 5: Serie and parallel aociation PV panel To obtain an increae of the generator voltage, we aociate ' N ' module in erie and to increae the current we aociate ' N ' module in parallel a hown in figure 5. p 3. THE DC-DC CONVERTER Fig. 6: Photovoltaic converion elementary chain Chopper are DC-DC converter for generating a variable DC voltage ource from a fixed DC voltage ource. We can model the boot converter with ordinary differential equation [5, 7]: C.dV L. c dv d t (1 k). V R (13) L V c L c co d t E (1 k). (14) V R. (15) L and C are electrical parameter of boot converter. V c, Voltage of capacity C. K, State of the interceptor (GBT: 1 ou 0). co, nitial capacitor current. L, the current acro the inductor. E, nput voltage. V, Output voltage {all thee device in the ideal cae cannot conume power, thi i the reaon of very good efficiency of converter}. The average output voltage V V i decribed by thi equation: V (1 ) (16) pv Where V dc and V pv are the output and input voltage of the converter and i the duty cycle of the witch T. 3.1 Realization of boot converter The power circuit contain: a) An electronic witch GBT 'RGPC60K";

6 42 H. Serghine et al. b) By pa diode ( D ) 'BYW29'; c) An R C D circuit: Reitance, Capacitor and Diode { R 1 = 100 W, C = 0.1 mf, D (N 54018)} i ued a a protection of the main witch (GBT). d) Storage ndicator ( L ). e) Filter capacitor ( C ). The control circuit: a) DSPACE interface: give the control pule of the GBT (ML) from MPPT program in Matlab oftware. The maximum output voltage of the DSPACE i 5 V. b) NPN tranitor 2N2222: it i ued to increae the amplitude of the pule coming from the dspace interface from 5 V to 15 V {voltage needed by the GBT witch in order to commutate}. c) An photo coupler HCPL-3100: it provide perfect galvanic iolation between input and output uing a quick LED, a photodiode, an amplifier and 2 tranitor. d) A Driver R2112: it provide ufficient pule amplitude to control the gate of GBT. e) Alimentation upply card: to alimented the component by 5V, 0V and 15V. 4. FSCC MPPT CONTROL METHOD Many tudie have hown that the ratio between optimal current {for which the output power i maximum} and hort circuit current i approximately contant. Thi i the bai of contant current operation which can be interpreted by the following equation: opt cc K 1 (17) cc n thi technique, we ued two identical panel. The firt i hort circuited on a current enor which i characterized by low reitance, it role i to meaure the hort circuit current of the firt panel and deduct the optimal (reference) current. The econd panel upplie the load via a parallel chopper and it control i determined a follow: The input current of the converter i compared with the reference current. The error between two current goe through a regulator hyterii to build the control pule of the main witch of the DC/DC converter Boot. Among the diadvantage of thi method i that it require an additional panel to meaure the hort-circuit current at any time, and alo to have a limited yield, becaue the coefficient of proportionality depend on the temperature of the cell, which can be very variable. Fig. 7: MPPT control technique FSCC

7 Deign and imulation of hortcut current MPPTracking technique to control boot Fig. 8: The complet ytem with MPPT 4.1 Simulation of FSCC MPPT method For imulation reult the value of the irradiation i about 320 W/m 2. Fig. 9: (a) Optimal current, (b) Meuared current, (c) PV voltage (d) Output voltage of the boot converter 4.2 Experimental reult The experimental and imulation reult of the value of the irradiation are about 320 W/m 2. Experimental reult verify the validity of our imulation. For imulation reult, input and output voltage contain a lot of noie becaue of the lack of information about the GBT parameter. n our imulation, we ue impower ytem GBT and diode model. The error between the meaured and optimal current i nearly zero. The meaured current follow with preciion of the optimal current (reference current) in imulation and alo in experimental reult.

8 44 H. Serghine et al. Fig. 10: Experimental reult 5. CONCLUSON n thi article we preented the MPPT technique by hort circuit current. The proper operation of the maximum power point tracking method of a photovoltaic ytem. Although it i efficient in term of PPM tracking, the hort circuit current MPPT method ha implicity of contruction and acceptable accuracy. At the ripple at the level of the error are due to the ocillatory characteritic of the hyterei regulator. REFERENCES [1] E.R. Shouman, E.T. El Shenawy and M.A. Badr, 'Economic Analyi of Dieel and Solar Water Pumping with Cae Study Water Pumping for rrigation in Egypt', nternational Journal of Applied Engineering Reearch, Vol. 11, N 2, pp , [2] K. Ghedami and D. Aouzellag, 'mprovement of the Performance for Wind Energy Converion Sytem', nternational Journal of Electrical Power & Energy Sytem, Vol. 32, N 9, pp , [3] Sarl BAOSEM, 'Guide de Energie Renouvelable', Minitère de l Energie et de Mine, Algérie, Edition [4] A. Data, G. Bhattacharya, D. Mukherjee and H. Saha, 'An Efficient Technique for Controlling Power Flow in a Single Stage Grid Connected Photovoltaic Sytem', Scientia ranica, Vol. 21, N 3, pp , [5] H. Bühler, 'Electronique de Puiance', Pree Polytechnique Romande, [6] Z. Ayache, A. Bendaoud, H. Slimani, B. Benazza, H. Miloudi et A. Bentaallah, 'Commande MPPT et Contrôle d un Sytème Photovoltaïque par la Logique Floue', Laboratoire RECOM, Univerité Djilali Liabè, Sidi Bel Abbè, 22000, Algeria. [7] J.A. Gow and C.D. Manning, 'Development of a Photovoltaic Array Model for Ue in Power electronic Simulation Studie', EEE Proceeding on Electric Power Application, Vol. 146, N 2, pp , [8] Q. Li and P. Wolf, 'A Current Fed Two-nductor Boot Converter with an ntegrated Magnetic Structure and Paive Lole Snubber for Photovoltaic Module ntegrated Converter Application', EEE Tranaction on Power Electronic, Vol. 22, N 1, pp , [9] E. Dirk, A.M. Gole, and T. Molinki, 'Performance evaluation of a building integrated photovoltaic array uing an internet baed monitoring ytem', in Proceeding of EEE Power Engineering Society General Meeting, pp. 1 5, 2006.