# PV Modules and Array

The schematic shown in fig. 20 illustrates how solar cells are connected within a solar module. The output power from a single PV cell is relatively small (approx­imately 0.5 W) [20]. To maximize voltage and power, a solar array is a must. A PV array consists of numerous solar modules that are combined in series and pa­rallel to form panels, and these panels are connected together to form the entire PV array. The architecture can be thought of similar to fig. 19 with modules re­placing the cells. So, in a micro grid, there may be numerous solar arrays con­nected to provide the required power to a load. The equations used to solve the module current are presented below, where the superscripts: C represents the solar cell, M represents the solar module, and A represents the solar array. Each solar module contains a manufacturer’s data sheet that contains parameters for standard operating conditions. The parameters used are related to the datasheet to test and validate the model as well.

Maximum power for cell

 (45)

 max, 0

 Fig. 20 PV Module with NSM Series Branches and NPM Parallel Branches

Open circuit voltage for cell

 (46)

Short circuit current for cell

 (47)

Thermal voltage of the cell

 (48)

Open circuit voltage of the module

 rC ОС, о vc Vt,0

 (49)

 VOC,0

Fill factor

Fill factor at standard conditions

vOC,0~^n{vOC,0 + 0.72)

ГГп

vOC, 0 + 1

 Equivalent series resistance

 FF FF0

 (52) (53) (54) (55) (56) (57)

 1

 Serial resistance of a cell

 t C ‘svOC,0 KS — ,c ‘sc, о

 Cell parameters for operating conditions with inputs are: VM, Ta, Ga Irradiation Parameters

 Short circuit operating current

 I sc — Ci Ga

 Working temperature of cell

 TL=Ta + C2Ga

 Open circuit voltage

 Vqc = V0cc, o – C3(TC – Г0С)

 Thermal voltage of cell

 (58)

 Calculated solar module current using cell parameters

 rC.,MRCNSM> SNpm

 Iм = l£rNp

 (59)

 1 — exp

 vCnSM

 Short circuit current for the module

 jM _ jC Ы ‘SC — ‘SCnPM

 (60)

 Open circuit voltage for module

Equivalent serial resistance for the cell

Thermal voltage of module

Module current

1 — exp

Module voltage

/,м _,м

Module power

pM = yMjM (66)

Also, array currents and voltage are calculated from the equations below.

Total current of array

1А = ҐЇ™1і (67)

Simplified total current of array

Iа = NsaVm (68)

Power generated by array

pA = yAjA (69)

Updated: October 27, 2015 — 12:10 pm