PHOTOVOLTAIC SYSTEMS Alessandro Massi Pavan Sesto Val Pusteria June 22 nd 26 th, 2015
GRID-CONNECTED PV PLANTS DISTRIBUTED TIPO DISTRIBUITO PV GENERATOR LOCAL LOADS INVERTER GRID CENTRALIZED PV GENERATOR INVERTER GRID
OFF-GRID PV PLANTS RESIDENTIAL PV GENERATOR STORAGE CHARGE CONTROLLER INVERTER AC LOADS INDUSTRIAL DC LOADS PV GENERATOR STORAGE CHARGE CONTROLLER DC LOADS
GENERATIONS OF PV MODULES Price [$/m 2 ]
FIRST GENERATION PV MODULES poly -Si mono -Si Glass EVA Solar cells EVA Tedlar Frame
SECOND GENERATION PV MODULES a - Si CdTe CIGS CdTe
ELECTRICAL PARAMETERS I-V CHARACTERISTIC STANDARD TEST CONDITIONS (STC) Irradiance 1.000W/m 2 - Cell Temperature 25 C - Ais Mass 1.5 PV MODULE Q.CELLS Q.PRO-G2 250 Nominal Power - P mp [Wp] 250 + [0-5] Short circuit current - I sc [A] 8.94 Open circuit voltage V oc [V] 37.78 Current at MPP I mp [A] 8.45 Voltage at MPP V mp [V] 29,89 Temperature coefficient of I sc z [%/K] +0.04%/K Temperature coefficient of V oc w [%/K] -0.33%/K Temperature coefficient of P mp P [%/K] -0.43%/K Number of cells [ ] 60 Fill factor FF [ ] 0.74 Degradation rate [%/year] 0.68 Nominal Operating Cell Temperature T NOCT [ C] 47±3 P mp A 1000 FF I sc P mp V oc
FIRST GENERATION PV MODULE Q.CELLS - QPRO
FIRST GENERATION PV MODULE Q.CELLS - QPRO
FIRST GENERATION PV MODULE Q.CELLS - QPRO
FIRST AND SECOND GENERATION PARAMETER Q.PRO 250 Generation 1 FS 280 Generation 2 P mp [Wp] 250 80 95 V mp [W] 29.9 71.2 62.1 I Mmp [W] 8.5 1.12 1.53 FF [ ] 0.74 0.72 0.72 η [%] 15.0 11.1 12.7 S 1kWp [m 2 ] 6.7 9.0 7.9 p [kg/kw p ] 79 150 139 Q.SMART 95 Generation 2
DEPENDANCE ON SOLAR IRRADIANCE Voltage [V]
DEPENDANCE ON CELL TEMPERATURE Voltage [V]
TWO DIODES MODEL Luque A, Hegedus S Handbook of photovoltaic science and engineering Wiley
TWO DIODES MODEL - I SC [A] is the short-circuit current when there are no parasitic resistances - I o1 [A]is the dark saturation current due to the recombination in the quasi-neutral region - I o2 [A] is the dark saturation current due to the recombination in the space-charge region - q [C] is the electron charge - R s [Ω] is the series resistance - R sh [Ω] is the shunt resistance - k [J/K] is the Boltzmann s constant - T [K] is the cell temperature The 5 parameters I SC, I 01, I 02, R S, R Sh are usually not listed in the data sheet of a PV device!!! 1. for the calculus of the 5 parameters 2. EMPIRICAL MODEL
EMPIRICAL MODEL - I [p.u.] is the per unit current referred to I sc - I L [p-u.] is per unit irradiance referred to 1.000W/m 2 - z [1/ C] is the current-voltage coefficient referred to I sc - T C [ C] is the solar cell temperature - m [ ] is an exponential factor - V [p.u.] is the per unit voltage referred to V oc - w [1/ C] is the voltage-temperature coefficient referred to V oc Massi Pavan A, Mellit A, Lughi V Explicit empirical model for general photovoltaic devices: experimental validation at maximum power point Solar Energy 101 pp. 105-116, 2014
INVERTERS For different applications exist centralized, string or module-inverters (hundreds of kva - 630kVA) String inverter 3kVA 50 x 40 x 20 cm Centralized Inverter 100kVA 120 x 80 x 140 cm Centralized Inverter 500kVA 210 x 240 x 60 cm
ELECTRICAL PARAMETERS SMA SUNNY BOY 3000TL Load [%]
POWER CONVERSION String 1 DC Boards STRING STRING GRID String n Voltage [p.u.] String 1 CENTRALIZED DC Board AC Board GRID String n Voltage [p.u.]
THANK YOU! apavan@units.it Sesto Val Pusteria June 22 nd 26 th, 2015