PV Module Simulink models

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Voltage input PV module. Inputs: • PV current IPV [A]. • Insolation [W/m2]. Outputs: • PV voltage VPV [V]. • PV output power Ppv [W]. This model is well suited for ...
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

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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

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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

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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

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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

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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

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