Download Simulink models of PV modules

PV Module
Simulink models
ECEN 2060
Spring 2008
Simulink models of PV modules
Current-input PV module
Ipv
PV module (I)
Insolation
Inputs:
Voltage input PV module
Vpv
Vpv
Insolation
Ppv
PV1
• PV current IPV [A]
• Insolation [W/m2]
Outputs:
• PV voltage VPV [V]
• PV output power Ppv [W]
This model is well suited for the case
when modules are connected in
series and share the same current
PV module (V)
Inputs:
Ipv
Ppv
PV1
• PV voltage VPV [V]
• Insolation [W/m2]
Outputs:
• PV current IPV [A]
• PV output power Ppv [W]
This model is well suited for the case
when modules are connected in
parallel and share the same voltage
Model parameters, in both cases, are the standard
PV module data-sheet parameters:
• short-circuit current Isc
• open-circuit voltage Voc
• rated current IR at maximum power point (MPP)
• rated voltage VR at MPP
under standard test conditions (1kW/m2, 1.5 AM,
25oC). A bypass diode (a single diode across the
entire module) can be included. Temperature
effects are not modeled.
ECEN2060
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PV cell circuit model and equations
KCL:
I SC
ISC
ID
VD
Rs
+
Rp
Diode characteristic:
_
PV cell
VD
− ID −
− I PV = 0
Rp
(
)
I D = I o eVD / VT − 1
KVL:
VPVcell = VD − Rs I PV
ECEN2060
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Simulink Implementation
• Both PV module models are implemented as masked subsystems in Simulink
• Look Under Mask (right-click or Edit menu) reveals details of the model
implementation
PV module (I)
• Details of the current-input PV module model:
Ipv
Vpv
Insolation
Ppv
PV1
Saturation
-Vt*log((u/Io)+1)
max
By-pass diode
MinMax
Rs
1
Ipv
2
Rs
Ipv
Product
Ppv
Diode
Ipv
Constant
2
Insolation
G
Isc
Insolation to
current gain
Inputs:
PV current and
insolation
ECEN2060
f (z)
Solve
f(z) = 0
z
Vd
Algebraic Constraint
Id
Io*(exp(u/Vt)-1)
PN-junction characteristic
Vd/Rp
1/Rp
1/Rp
Vpv cell
1
Ns
Switch
Vpv
Ns
Outputs:
PV voltage and
PV power
4
Inside the current-input PV module model
Saturation
-Vt*log((u/Io)+1)
max
By-pass diode
MinMax
Rs
1
Ipv
2
Rs
Ipv
Product
Ppv
Diode
Ipv
Constant
2
G
Insolation
Isc
Insolation to
current gain
f (z)
Solve
f(z) = 0
z
Vd
Vpv cell
Algebraic Constraint
Id
Io*(exp(u/Vt)-1)
Vd/Rp
VPV = N sVPVcell
1/Rp
N s = number of cells in series
1/Rp
I SC
KCL solved for VD
using Algebraic
Constraint block
ECEN2060
Switch
Vpv
Ns
PN-junction characteristic
V
− I D − D − I PV = 0
Rp
1
Ns
VPVcell = VD − RS I PV
(
)
I D = I o eVD / VT − 1
5
Inside the current-input PV module model
Saturation
1
Ipv
-Vt*log((u/Io)+1)
max
By-pass diode
Bypass diode current
cannot be negative
MinMax
Rs
2
Rs
Ipv
Product
Ppv
Diode
Ipv
Constant
2
Insolation
G
Insolation to
current gain
Isc
f (z)
Solve
f(z) = 0
z
Vd
Algebraic Constraint
Id
Vpv cell
1
Ns
Switch
Vpv
Ns
Io*(exp(u/Vt)-1)
PN-junction characteristic
Vd/Rp
1/Rp
1/Rp
 I bypass

+ 1
VDbypass = Vt ln
 Io

Select VPV with
bypass diode
(“Diode” = 1) or
without bypass diode
(“Diode” =0)
Bypass diode voltage
(if forward biased)
ECEN2060
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Model Mask: Parameters
• Edit Mask (right-click or Edit menu), click on Parameters
• This is where the masked subsystem model parameters are defined
ECEN2060
7
Model Mask: Initialization
• Edit Mask (right-click or Edit menu), click on Initialization
• The MATLAB code computes model parameters Io, Rs, Rp based on the model parameters
(short-circuit current Isc, circuit voltage Voc, rated voltage Vr, and rated current Ir)
ECEN2060
8
Application Example: PV Array
PV array consisting
of 6 PV modules
connected in series
Ipv
1000
PV module (I)
Insolation
Vpv
ECEN2060
6-module PV Array
Ppv
PV1
Insolation
IPV
Ipv
PV module (I)
Insolation
Vpv
Ppv
PV2
+
Ipv
PV module (I)
Insolation
PV
To Workspace
Vpv
Ppv
Vpv
PV3
Ipv
PV module (I)
Insolation
VPV
Vpv
XY V-I
Vpv
Ppv
PV4
Ppv
Ppv
Ipv
PV module (I)
Insolation
Product
Vpv
Ppv
PV5
Ipv
PV module (I)
Insolation
_
XY power
Vpv
Ipv
Simulink model
pv_array.mdl
Ppv
PV6
Add
Ipv Ramp
Ipv
ECEN2060
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Inside the voltage-input PV module
Vpv
PV module (V)
Insolation
Ipv
Ppv
PV1
1
Vpv
Ipv
2
Vpv
Insolation
Insolation
Ppv
f (z)
Solve
f(z) = 0
z
Algebraic Constraint
PV module (I)
1
Ipv
2
Ppv
Inputs:
PV voltage and
insolation
Current-input
PV model
ECEN2060
Algebraic
Constraint block
solves for IPV that
results in VPV
Outputs:
PV voltage and
PV power
10
Application Example: PV Module Characteristics
Simulink model:
pv_characteristic.mdl
Vpv
Vpv
Vpv
PV power
Ipv
Vpv
PV module (V)
Insolation
Insolation
I-V characteristic
Ipv
Ppv
PV1
Insolation = 200, 400, 600, 800, 1000 W/m2
IPV
ECEN2060
PPV
VPV
VPV
11