Analysis of PV Efficiency with Incremental Conductance MPPT Technique under Non-

Linear Loading Conditions

P.Sivakumar

A.Abdullah

K.Yogeshraj

M.Arutchelvi

OBJECTIVE Enhanced Energy utilization of PV

sources during nonlinear loads

Analysis of PV array with conventional

MPPT technique

Modification of instantaneous

conductance with respect to variable

conductance value

Cost efficient energy utilization

Functional Block Diagram

Incremental Conductance

The output voltage and output current from the PV

panel are measured using sensors to calculate the

conductance (C=Ip/Vp) and incremental conductance

(ΔC=ΔIp/ΔVp).

The slope of the PV array power curve is zero at the

MPP, positive on its left, and negative on the right.

The panel current Ip as a function of load impedance

is calculated as,

lsh

psp

j

pspsphZp Z

R

IRV

AKT

IRVqIII

l

)1)

)((exp()(

Simulation Results

The simulation circuit consists of a 150mH

inductor and 22µF capacitors for Buck-Boost

converter stage, 5mH inductor and a 90µF

capacitor for Boost converter stage, 0.5mH

inductor for Buck converter stage.

A resistive load of 125Ω was used commonly for

all stages. The system was simulated under

controlled and un-controlled converter loads.

PV Model

PV MODEL

R1

2

S-

1

S+

v+ -

V

RP n Rse

s -+

Isc

i+ -

IM

s -+

ID

s -+

I

f(u)Fcn1 f(u)Fcn

3Ise

2

Voc

1

R

Electrical Parameters of the PV Cell under STP

Maximum Power P MAX=100WP

Voltage at MPP VMPP=17.8V

Current at MPP IMPP=5.62A

Open Circuit Voltage VOC=21.8V

Short Circuit Current ISC=6.2A

Temperature Coefficient of ISC =2.46×10-3

A/˚C

Inverter Model

M1 M3

M2M4

INVERTER

4

o/pNeutral

3

o/pPhase

2

DC i/p+ve

1

DC i/p-ve

Out1

Out2

PulseGeneration g D

S

g DS

g DS

g DS

Buck-Boost MPPT Model

I

BUCK-BOOST MPPT MODEL4

DC o/p -ve

3

DC o/p +ve

2

DC i/p -ve

1

DC i/p +ve

g DS

u y

fcnMPPT

Function

2

1

V

T1 T3

T2 T4

NON-LINEAR LOAD

2

i/p Neutral

1

i/p Phase

g ak

g ak

g ak

g ak

Non-Linear Load Model

Discrete,Ts = Ts s.

powergui

v+-

v+-

VOLT

sim

RES

PV MODEL

NON-LINEAR LOAD

DC i/p +v e

DC i/p -v e

o/p Phase

o/p Neutral

INVERTER

IMM

[Pac]

[Vac]

[Vdc]

[Iac]

[Pdc]

[Idc]

[Pdc]

[Iac]

[Vac]

[Idc]

[Vdc]

[Idc]

[Idc]

[Vdc]

[Pac]

[Iac]

[Vac]

[Vdc]

V

I

DC i/p -v e

DC i/p +v e

DC o/p +v e

DC o/p -v e

DC-DC BUCK-BOOSTMPPT

i+ -

i+ -

Overall Simulation

Current and Voltage waveforms using a DC-DC Buck-Boost converter with controlled converter load.

Current and Voltage waveforms using a DC-DC Buck converter with fully controlled converter load

Hardware Setup

The improved technique offers a 10 Watt-Hour energy saving for a 100 WP PV panel.

When calculated for a month’s usage (6 hours a day) would account for 1.8 kW that attributes for the reduction in cost of energy consumption.

Experimental Results

The experimental results were obtained from the setup

consisting of a PV source with DC-DC buck-boost MPPT

connected to a PWM inverter feeding a fully controlled

converter load.

TMDSSOLAREXPKIT, which has a solar inverter with a

MPPT Boost DC-DC converter, was used for MPPT

control and the processor control card TMS320F28035

Variation of Efficiency

RMS Current(Amps)

RMS Voltage(Amps) Mean

Current(Amps)

Mean Voltage(Volts)

RMS Power

(Watts)

Mean Power(e)

(Watts)

MeanPower(i)

(Watts)

Efficiency(Existing)

(%)

Efficiency(Improved)

(%)

(1) 17.6 443 11.5 416 7796 4790 6200 61.2 78.3

(2) 13.3 511 11.5 416 6796 4790 6200 61.2 78.3

(3) 9 540 6 540 4860 3240 3600 40.8 46.5

(4) 7 540 6 540 3780 3240 3600 40.8 46.5

(5) 26 430 24 290 11180 6960 7900 89.8 96.6

(6) 24 400 24 290 9600 6960 7900 89.8 96.6

Conclusion From the experiment and simulation result it is

clear that the IC technique fails to attain

Maximum power point when PV is loaded with

non-linear load

By varying the conductance along with the

load conductance the efficiency of the system

is improved

A 2kWh saving would result in the reduction of

898 INR for the same calculated duration of

utilization based on the tariff of Tamilnadu

Generation and Distributed Corporation

limited, India.

It is a Enhanced cost Efficient system.

?

Thank you

Go green Initiative , letz support green energy