PV ModuleSimulink models

ECEN 2060Spring 2008

2ECEN2060

Simulink models of PV modules

Vpv

Insolation

Ipv

Ppv

PV module (V)

PV1

Ipv

Insolation

Vpv

Ppv

PV module (I)

PV1

Current-input PV module 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 the case when modules are connected in series and share the same current

Inputs:• 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.

3ECEN2060

PV cell circuit model and equations

PV cell

+

_

Rs

RpVD

IDISC

0=−−− PVp

DDSC I

RVII

( )1/ −= TD VVoD eII

PVsDPVcell IRVV −=

KCL:

Diode characteristic:

KVL:

4ECEN2060

2Ppv

1Vpv

Switch

Saturation

Rs

Rs

Product

Io*(exp(u/Vt)-1)

PN-junction characteristic

Ns

Ns

max

MinMax

G

Insolation to current gain

Diode

Constant

-Vt*log((u/Io)+1)

By-pass diode

f (z) zSolve

f(z) = 0

Algebraic Constraint

1/Rp

1/Rp

2Insolation

1Ipv

Isc

Ipv

Ipv

Vd Vpv cell

Id

Vd/Rp

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• Details of the current-input PV module model:

Ipv

Insolation

Vpv

Ppv

PV module (I)

PV1

Inputs:PV current andinsolation

Outputs:PV voltage and

PV power

5ECEN2060

2Ppv

1Vpv

Switch

Saturation

Rs

Rs

Product

Io*(exp(u/Vt)-1)

PN-junction characteristic

Ns

Ns

max

MinMax

G

Insolation to current gain

Diode

Constant

-Vt*log((u/Io)+1)

By-pass diode

f (z) zSolve

f(z) = 0

Algebraic Constraint

1/Rp

1/Rp

2Insolation

1Ipv

Isc

Ipv

Ipv

Vd Vpv cell

Id

Vd/Rp

Inside the current-input PV module model

0=−−− PVp

DDSC I

RVII

KCL solved for VDusing Algebraic Constraint block

( )1/ −= TD VVoD eII

PVSDPVcell IRVV −=

PVcellsPV VNV =

seriesin cells ofnumber =sN

6ECEN2060

2Ppv

1Vpv

Switch

Saturation

Rs

Rs

Product

Io*(exp(u/Vt)-1)

PN-junction characteristic

Ns

Ns

max

MinMax

G

Insolation to current gain

Diode

Constant

-Vt*log((u/Io)+1)

By-pass diode

f (z) zSolve

f(z) = 0

Algebraic Constraint

1/Rp

1/Rp

2Insolation

1Ipv

Isc

Ipv

Ipv

Vd Vpv cell

Id

Vd/Rp

Inside the current-input PV module model

+= 1ln

o

bypasstDbypass I

IVV

Bypass diode current cannot be negative

Bypass diode voltage (if forward biased)

Select VPV with bypass diode (“Diode” = 1) or without bypass diode (“Diode” =0)

7ECEN2060

Model Mask: Parameters• Edit Mask (right-click or Edit menu), click on Parameters• This is where the masked subsystem model parameters are defined

8ECEN2060

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)

9ECEN2060

Application Example: PV Array

ECEN20606-module PV Array

XY power

XY V-I

PV

To Workspace

Product

Ipv

Insolation

Vpv

Ppv

PV module (I)

PV6

Ipv

Insolation

Vpv

Ppv

PV module (I)

PV5

Ipv

Insolation

Vpv

Ppv

PV module (I)

PV4

Ipv

Insolation

Vpv

Ppv

PV module (I)

PV3

Ipv

Insolation

Vpv

Ppv

PV module (I)

PV2

Ipv

Insolation

Vpv

Ppv

PV module (I)

PV1

Ipv Ramp

1000

Insolation

Add

Ipv

Ipv

VpvVpv

PpvPpv

PV array consisting of 6 PV modules connected in series

+

_

VPV

IPV

Simulink model pv_array.mdl

10ECEN2060

Inside the voltage-input PV module

2Ppv

1Ipv

Ipv

Insolation

Vpv

Ppv

PV module (I)

f (z) zSolve

f(z) = 0

Algebraic Constraint2Insolation

1Vpv

Vpv

Insolation

Ipv

Ppv

PV module (V)

PV1

Inputs:PV voltage andinsolation

Outputs:PV voltage and PV power

Current-input PV model

Algebraic Constraint block solves for IPV that results in VPV

11ECEN2060

Application Example: PV Module Characteristics

Vpv

Vpv

Insolation

Ipv

Ppv

PV module (V)

PV1

PV power

Insolation

I-V characteristic

VpvVpv

Ipv

Simulink model: pv_characteristic.mdl

IPV PPV

VPVVPV

Insolation = 200, 400, 600, 800, 1000 W/m2