Grid-Connected MPPT Control for MG Operating under Partially Shaded Condition - Intelligent Computing for Sustainable Energy and Environment - page 50

exceeds the maximum output current of the cell under shading, the bypass diode turns
on. Assuming the forward voltage of the bypass diode is zero, then, the output
voltage, the open circuit voltage and the equivalent series resistance of the series PV
cells are given as:




UNNU
UNNU
R

=− ( )

A S D

(6)

=− ( )




ocA S D oc

=− ( NNR )



sA S D s

where N D is the number of PV cells under the shadow in series connection.

500

400

300

200

100

0

0 50 100 150

(a) The PSC ratio to the normal condition is 1,0.7,0.5

U(V)

500

400

300

200

100

0

0 50 100 150

(b) The PSC ratio to the normal condition is 1,0.6,0.2

U(V)

500

400

300

200

100

0

0 50 100 150

(c) The PSC ratio to the normal condition is 1,0.3,0.1

U(V)

Fig. 3. P-Vcurves of PV panels under partial shading conditions