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ELECTRIMACS 2002, 7th International Conference on
Modeling and Simulation of Electric Machines,
Converters and Systems August 18th through 21st
2002
ANALYSIS AND EXPERIMENTAL VALIDATION OF VARIOUS
PHOTOVOLTAIC SYSTEM MODELS O. GERGAUD, B.
MULTON, H. BEN AHMED LÉSiR Brittany Branch,ENS
de Cachan Ker Lann campus 35170 BRUZ
FRANCE Phone[phone] Fax [phone]
93 28 gergaud_at_bretagne.ens-cachan.fr
PHOTOVOLTAIC CONVERSION CHAIN
ENERGY ANALYSIS
Within the framework of the optimization of the
dimensionnement and\or the management of the
transfers of energy of a joint photovoltaic and
wind production system hooked up to the network
via a continuous bus bar and associated with an
electrochemical storage device One wishes to
determine the characteristic of the power
supplied in the continuous bus, Pbat, according
to the weather and electric conditions, that is
the illumination in the plan of the sun panels
Esd, their temperature Tj, as well as the level
of the tension of the continuous bus, Vbat. The
model should be at the same moment enough
handbook and enough express.
comparison of measurements with GROUP 1 "
two-diode model" over one day production period
(Dec. 17, 2001)
comparison of measurements with GROUP 1
"one-diode model" over one day production period
(Jan. 24, 2002)
ELECTRICAL MODELS OF THE PANELS

• photocurrent

Iph P1. Es. 1 P2. ( Es Eref ) P3 . (Tj
Tjref)

• polarization current of the junction PN

CHARACTERISTICS OF THE MPPT CONVERTERS

• saturation current

• Efficency model

• Ps converter output power,
• P0 empty converter losses,
• K1 a coefficient representing the losses
  proportional to the square of the current 
• K2 losses proportional to the current.

• final equation of the model

7 parameters P1, P2, P3, P4, A, Rs and Rsh to be
determined

• P0 being measured, calculated K1 and K2

COMPLETE SYSTEM
two diodes are present for the PN junction
polarization phenomena 8 parameters P1, P2, P3,
P4, A, Rs and Rsh to be determined

• Simulation of the complete system on sevral days
  

measurements
1000 800 600 400 200 0
Insolation (W/m²)

• final equation of the model

March 31, 02
April 1, 02 April 2, 02
April 3, 02 April
4, 02
mesures / simulation
25 20 15 10 5 0
Energy produced (kWh)
March 31, 02
April 1, 02 April 2, 02
April 3, 02 April
4, 02
simulation-mesures
3 parameters P1, P2, P3 to be determined
0.1 0 -0.1 -0.2 -0.3 -0.4
Simulation error (kWh)
DETERMINATION OF PARAMETERS VALUES - POWER
ANALYSIS

• Identification of the parameters by genetic
  algorithm
• For both first models, resolutiin of an implicit
  function
• IGthéo f ( IGthéo, VGréelle, Es, Tj )
  IGthéo f ( IGreèlle, VGréelle, Es, Tj )
• Minimization of the error
• For the model polynomial determination of the
  parameters from the maxima of the characteristics
  power / tension real of the PV

March 31, 02
April 1, 02 April 2, 02
April 3, 02 April
4, 02

• Errors on the energy produced during the March
  30 - April 4 2002 recording campaign,
  Measurement/Model comparison

• Very good energy depiction of troid presented
  models
• The errors identified lie below the 2 level,
  they may just as easily stem from insolation,
  temperature and power production measurements as
  they may from our models
• Shorter time of calculations in the cas of the
  polynomial model

The polynomial model has therefore been selected
for subsequent use in modeling the photovoltaic
chain as part of our system optimization efforts