Artigo MPPT

Prévia do material em texto

Matlab/Simulink Model of Solar PV Array with Perturb 
and Observe MPPT for Maximising PV Array 
Efficiency 
 Oladimeji Ibrahim, Member IEEE Nor Zaihar Yahaya, Member IEEE, 
 Department of Electrical and Electronics Engineering Nordin Saad, Member IEEE 
 Universiti Teknologi PETRONAS, Muhammad Wasif Umar 
 Bander Seri Iskander, Perak 32610, Malaysia Universiti Teknologi PETRONAS 
 reacholaibrahim@gmail.com Bandar Seri Iskandar, Perak 32610, Malaysia 
 norzaihar_yahaya@petronas.com.my 
 nordiss@petronas.com.my 
 cmwasif@yahoo.com 
 
Abstract—The efficiency of commercially available solar PV module 
is very low in the range of 10-25 %. In order to maximise their 
operating efficiency and to reduce installation cost, maximum 
power point trackers (MPPT) are coupled with the system. The 
output power of solar PV depends on solar irradiance level, 
incident angle, temperature and load current which all contribute 
to non-linear varying I-V characteristic during operation. MPPT 
ensures that a PV cell, module or panel is operated and maintained 
at the reference voltage that correspond to maximum power point 
for particular operating solar irradiance and cell temperature. A 
220 W solar PV panel is modelled in Matlab-Simulink to study 
solar PV characteristics under different solar irradiance and 
working cell temperature. A Perturb & Observation MPPT 
technique incorporated for maximising the output power of the PV 
panel shows that the percentage deviation from the ideal PV power 
is about 10 % for different operating solar irradiance and cell 
temperature. 
Keywords: Solar PV; Perturb and Observe; Solar Irradiance; DC-DC 
boost converter; PV cell temperature 
I. INTRODUCTION 
 Solar energy is a readily available, clean, and inexhaustible 
energy source considered as a sustainable alternative energy 
source for electricity generation. The contribution of solar 
energy to the world total electricity generation has been on 
increase in the past decades. The global installed capacity of 
solar photovoltaic (PV) system increased from below 10 GW in 
2007 to over 100 GW capacity in year 2012 [1]. Solar energy 
system generates electricity by direct conversion of solar photon 
(light) energy to electricity using solar cells and indirectly using 
solar thermal to produce superheated steam for driving electrical 
turbines. Solar photovoltaic cells used in solar PV system are 
made of a light absorber materials of p-n junction semiconductor 
that absorbs solar photons above certain minimum threshold 
energy called “energy gap” or “band gap” (Eg) to free electrons 
generate electricity. 
 The performance of a PV cell largely depends on quality of 
cell material such as absorption capacity and reflectance of the 
surface. The operating condition like solar irradiance level, 
incident angle, temperature and load current plays a big role in 
dictating the performance of PV array output voltage, current 
and power delivery [2, 3]. The available commercial solar PV 
cells have low efficiency in the range of 10-25 % necessitating 
the need to ensure that maximum available power is extracted 
for better utilization efficiency and cost reduction. Research 
effort in solar energy studies are directed towards increasing cell 
efficiency via manufacturing technologies, improving power 
quality of PV power generation for grid connection and 
extracting maximum output power termed maximum power 
point tracking (MPPT). 
 MPPT are used for operating PV array at the point of 
maximum power irrespective of irradiance, temperature and load 
current variation. In literature, different MPPT techniques have 
been proposed but their suitability largely depends on factors 
like the end application, dynamic of irradiance, design 
simplicity, convergence speed, hardware implementation and the 
cost [4]. The available MPPT methods ranges from simple 
voltage relationships to complex multiple sample based analysis 
which includes but not limited to constant voltage method, short 
current pulse method, open voltage method, perturb and observe 
method, incremental conductance method, and temperature 
method [5]. The design and implementation simplicity coupled 
with good performance has make perturb and observe (P&O) 
MPPT to be one of the most widely used MPPT techniques for 
solar PV applications [4, 6]. 
 This paper presents studies on solar PV model module, the 
energy pattern was investigated under different operating 
weather conditions and MPPT was incorporated to maximize 
energy harvesting. A model a 220 W solar PV panel intended to 
be fed to an inverter for stand-alone AC network system is 
This work was supported by Electrical & Electronics Engineering, Universiti 
Teknologi PETRONAS 
254978-1-4799-8598-2/15/$31.00 ©2015 IEEE
 
modelled in Matlab-Simulink environment. T
behaviour of the PV panel is analysed cons
operating conditions of irradiance and tempe
P&O MPPT algorithm was used for maximum
The simulation results shows that sys
satisfactorily as the maximum output power from
with MPPT show a close relationship with the m
available from the PV under test at different irra
II. MODELING OF SOLAR PV CE
 Solar PV cell is the basic unit of solar PV 
are combined in series and parallel to achieve
and current level. A PV cell is a p–n junction se
generate current when exposed to light. Th
model of PV cell is useful for simulation purp
voltage, current and power behaviour under di
conditions. A simplified equivalent circuit of
parameter is presented in Fig. 1. A cell series r
connected in series with a parallel comb
photocurrent�ሺܫ௣௛ሻ, exponential diode�ሺܦ),
resistanceሺܴ௦௛ሻ . ܫ௉௩ , and ௉ܸ௩ are the PV c
voltage respectively. 
Fig. 1. Equivalent circuit of PV cel
The PV cell output current ܫ௉௩ is expressed as: 
( ) ( PVPVsphPV IvIII nKT
q sRIV PVPV
e 1 +−¸¸¹
·
¨¨©
§
−−=
∗+
Where: 
phI = Solar-induced current 
sI = Diode saturation current 
q = Electron charge )6.1( 19Ce− 
K = Boltzmann constant )/38.1( 23 KJe− 
n = Ideality factor )2~1( 
T =Temperature K0 
The solar induced current of the solar PV cell
solar irradiation level and the working temperat
eq. (2): 
 
1000
)( r
r
T
c
T
i
KscIphI
I
∗−+= 
scI = short-circuit current of cell at STC 
i
K = cell short-circuit current/temperature coefficient
 
The characteristic 
idering different 
erature level and 
m power tracking. 
stem performed 
m solar PV panel 
maximum power 
adiance levels. 
ELL 
array/panel, they 
e require voltage 
miconductor that 
he mathematical 
ose to reveal the 
ifferent operating 
f PV cell with 5 
resistance ሺܴ௦ሻ is 
bination of cell 
, and shunt 
ell’s current and 
 
ll 
) shsV RR /∗ (1) 
l depends on the 
ture expressed as 
 (2) 
t )/( KA 
rI = irradiance in W/m
2 covering ce
r
T
c
T , = cell working and reference temp
 To show the non-linear charac
different irradiance and temperat
comprises of 3 modules with ea
connected in series. The electrica
panel based on standard test cond
irradiance, AM of 1.5 and, 25 °C is 
TABLE I: ELECTRICAL CHARAC
Parameters 
Ratedpower 
Open circuit voltage 
Short circuit current 
Voltage at maximum power 
Current at maximum power 
Total number of cells in series 
Total number of cells in parallel 
 Matlab-Simulink tools was used
I-V and P-V curve under variable i
presented in Fig. 2. The simulat
characteristic at 1000 W/m2, 80
irradiance at constant temperature o
and Fig. 4 respectively. The resul
current and power increases as solar
Fig. 2. Simulink mode
Fig. 3. I-V curve for d
ll surface 
perature at STC 
cteristic of PV array under 
ture, a 220 W solar panel 
ach module having 36 cells 
al specifications of the solar 
ditions (STC) at 1000 W/m2 
presented in Table I. 
CTERISTICS OF PV PANEL 
Symbol Value 
P MP 220W 
V OC 54V 
I SC 5.52A 
V MP 44.63V 
I MP 4.94A 
N S 108 
N P 1 
d to simulate the solar panel 
irradiance and temperature as 
tion result of I-V and P-V 
00 W/m2, and 600 W/m2 
of 25 °C is presented in Fig. 3 
lt shows that the PV output 
r irradiance increase. 
 
l of solar panel 
 
different solar irradiance 
255
 
Fig. 4. P-V curve for different solar i
 The simulation result of I-V and P-V charact
panel for different working temperature 25 °C, 
with constant irradiance are shown in Fig. 5 and
output voltage and power decreases with incr
operating temperature. 
Fig. 5. I-V curve for different cell tem
Fig. 6. P-V curve for different cell tem
III. MPPT CONTROL TECHNIQU
 PV arrays exhibits non-linear varying I-
during operation based on solar irradiance and
particular time. In order to ensure that PV ar
maximum power point under different opera
maximum power point tracker (MPPT) are inc
will improve the PV panel efficiency and re
 
 
irradiance 
teristic of the PV 
50 °C and 75° C 
d Fig. 6. The PV 
reasing solar cell 
 
mperature 
 
mperature 
UE 
-V characteristic 
d temperature at 
rrays operates at 
ating conditions, 
corporated. This 
duce the system 
installation cost. MPPT automa
(reference voltage ሺ ௥ܸ௘௙ሻ at wh
maximum power and ensure tha
operation at the point under differen
load current. The basic unit of max
shown in Fig. 7 with MPPT power
algorithm [7]. 
M
po
ci
MPPT 
control 
algorithm
VPV,IPV
PV Array
 Fig. 7. Block diagram of M
 In this work, a DC-DC boost con
to achieve the source to load imped
variable switching duty cycle. Th
(P&O) MPPT algorithm is used for 
obtain reference voltage for maxim
chart of P&O algorithm is show
voltage and current are sensed to o
power is checked by varying the v
the power also increased, then the d
the same direction otherwise du
stepሺ߂ܦሻ. The iteration continues u
reached and the converter output 
point [8-11]. 
 The output voltage ሺ ௢ܸ௨௧ሻ of 
constant by varying the duty cycle 
voltage value from the solar PV at
solar PV array output voltage whic
defined by (3) [12]: 
 ouPV VDV )1( −=
The solar irradiation or temperatur
array output voltage variation expre
 PV DV /// Δ=Δ
Where PVVΔ and DΔ are the PV 
duty cycle variations. The MPPT
Matlab m file and embedded in 
function block. In order to ensur
oscillation around the maximum po
at the same time achieving fast tr
change was DΔ chosen as 0.0005. 
atically finds the voltage 
hich the PV array outputs 
at it maintains the system 
nt irradiance, temperature and 
ximum power point tracker is 
r stage and the MPPT control 
MPPT 
ower 
ircuit
Load
Vo,Io
D
 
MPPT control 
nverter is used at power stage 
dance matching controlled by 
he Perturb and Observation 
the duty cycle ሺܦሻ control to 
mum power point. The flow 
n in Fig. 8, where the PV 
obtain the output power. The 
voltage, with increase voltage 
duty cycle ሺܦሻis increased in 
uty cycle decreases with a 
until maximum power point is 
voltage is maintained at the 
the converter is maintained 
which determines the output 
t every switching cycle. The 
ch is input to the converter is 
ut (3) 
re changes will results in PV 
essed as: 
outV/ (4) 
output voltage and converter 
T P&O coding was done in 
the Simulink using Matlab-
re that the possible voltage 
ower point is minimised and 
racking, the duty cycle step 
256
 
P(k)>P(k-1)
Sample V(k), I(k)
Start
P(k) = V(k)*I(k)
V(k)>V(k)>V(k-1)
D=D1+ǻD D=D1+ǻD
k = k+1
Return
Y
YY
N
N
D=D1-ǻD
 Fig. 8. Flow chart of P&O MPPT metho
 A DC-DC boost converter is used to ach
power stage owing to the advantage of high
component parts to reduce implementation c
converter configuration comprises of power M
switching transistor with input inductor ሺܮሻ plac
the PV voltage ሺ ௜ܸ௡ሻ as shown in Fig. 9. The
parameters used in this project is shown in Table
ic(t)
Vc(t)
D
L
1Q
PWM
iL(t)
Vin
iin(t)
Fig. 9. Equivalent circuit of DC-DC boost con
The steady state conversion ratio (input-outpu
converter is given by: 
 
D
VV inout
−
=
1
 
The magnitude of peak-to-peak inductor curre
given by: 
 
Lf
DVI
s
in
L =Δ 
And, also the output capacitor voltage ripple VΔ
 
Cf
DIVV
s
o
outc =Δ=Δ 
 
 
 
>V(k-1)
D=D1-ǻD
N
 
od 
hieve the MPPT 
h reliability, less 
cost. The boost 
MOSFET as the 
ced in series with 
e boost converter 
e II. 
+
-
C
Vout(t)RL
 
nverter 
ut voltage) of the 
 (5) 
ent ripple LIΔ is 
 (6) 
cV is: 
 (7) 
TABLE II: BOOST CONVE
Parameters Symbol
Input voltage inV 
Output voltage outV 
Load resistance LR 
Inductor L 
Output capacitor C 
Switching frequency sf 
 
IV. RESULTS AND
 The Matlab_Simulink model of 
MPPT controller is presented in
performance of the MPPT at di
temperatures is presented in Fig. 10
from the PV at different solar irr
W/m2, 600 W/m2 and cell temperatu
presented in Fig. 11 and Fig. 12 re
decrease in MPPT duty cycle and
irradiance decreases and with cell te
output power from application of
maximum available power from th
The comparative output power resul
Fig. 10. Simulink model of P
Fig. 11. Duty cycle and PV output po
ERTER PARAMETERS 
l Value 
45 [V] 
90 [V] at D=0.5 
36.8 [Ÿ] 
500 [μH] 
100 [μF] 
5 [kHz] 
D DISCUSSIONS 
f PV panel developed with the 
n Fig. 10 for studying the 
fferent irradiances and cell 
0. The results of output power 
radiance of 1000 W/m2, 800 
ure of 25 °C, 50 °C, 75 °C are 
espectively. The results show 
d PV output power as solar 
emperature increases. The PV 
f MPPT power is closed to 
he PV panel test parameters. 
lts are given in Table III. 
 
PV array with P&O MPPT 
 
ower at 25 °C cell temperature 
257
 
Fig. 12. Duty cycle and PV output power at 1000 W/
TABLE III: COMPARISON OF PV AND MPPT OUT
Constant cell temperature of 25°C 
Solar Irradiance 
(W/m2) 
PV maximum 
power (watt) 
PV with P&O ou
power P PV (wa
1000 220.47 213.31 
800 172.87 154.11 
600 125.82 113.67 
Constant solar irradiance of 1000W/m2 
Cell temperature 
(°C) 
PV maximum 
power (watt) 
PV with P&O ou
power P PV (wa
25 220.47 213.31 
50 185.34 174.32 
75 151.46 139.95 
 
V. CONCLUSIONS 
 A solar PV panel has been modelled and per
MPPT technique is developed for maximisin
efficiency. Studies on the solar PV Simulink m
nonlinear I-V and P-V characteristics of th
different solar irradiance of 1000 W/m2, 800 W
and cell temperature of 25 °C, 50 °C, 75 °C.
power decreases as the irradiancelevel decrea
working temperature of the PV cells rises. T
technique used for maximising the output power
is able to effectively operate the system at a poi
maximum available power from the PV pan
percentage deviation of the PV output power fr
power is about 10 % for the tested operating c
irradiance and cell temperature. 
 
 
 
 
/m2 irradiance 
TPUT POWER 
utput 
att) 
% deviation 
3.25 
10.85 
9.66 
utput 
att) 
% deviation 
3.25 
5.96 
8.22 
rturb and observe 
ng its operating 
model shows the 
he PV panel to 
W/m2, 600 W/m2 
. The PV output 
ase and when the 
The P&O MPPT 
r of the PV panel 
int very closed to 
nel source. The 
rom the ideal PV 
condition of solar 
ACKNOWLE
The authors would like to thank Unive
financial support in the publication of th
 
REFEREN
[1] REN21. (2012). Renewables
Available: Available at: 
GSR2012_low.pdf [Retrieved
[2] D. Shmilovitz, "On the con
power point tracker via outpu
Applications, IEE Proceeding
[3] A. Cupertino, J. de Resende, 
Grid-Connected Photovoltaic 
Point Tracker using Passivi
Boost Converter," the solar sy
[4] T. Esram and P. L. Chapma
array maximum power poi
TRANSACTIONS ON ENERG
p. 439, 2007. 
[5] D. Freeman, "Introduction to 
power point tracking," 
d'application SLVA446-Novem
[6] S. Jain and V. Agarwal, "Co
maximum power point track
stage grid-connected photov
Power Applications, vol. 1, pp
[7] M. Killi and S. Samanta, "
MPPT Algorithm for Drif
Systems," IEEE Transactions
62, pp. 5549-5559, 2015. 
[8] A. Dolara, R. Faranda, and S
seven MPPT techniques f
Electromagnetic Analysis and
[9] A. K. Abdelsalam, A. M. Ma
"High-performance adaptive
technique for photovolta
Transactions on Power Elect
2011. 
[10] M. Mohd Zainuri, M. Radzi,
Rahim, "Development of ada
control maximum power poin
dc-dc converter," Renewable 
pp. 183-194, 2014. 
[11] M. A. De Brito, L. P. Samp
"Comparative analysis of 
applications," in Internati
Electrical Power (ICCEP), 20
[12] F. Liu, Y. Kang, Y. Zhang,
P&O and hill climbing MPPT
converter," in 3rd IEEE Conf
and Applications, 2008. ICIEA
 
 
 
DGMENT 
ersiti Teknologi PETRONAS for 
his work. 
NCES 
s 2012 Global Status Report. 
http://www.map.ren21.net/GSR/ 
d December, 2013] 
ntrol of photovoltaic maximum 
ut parameters," in Electric Power 
gs-, 2005, pp. 239-248. 
H. Pereira, and S. S. Júnior, "A 
System with a Maximum Power 
ity-Based Control applied in a 
ystem, vol. 4, p. 6, 2012. 
an, "Comparison of photovoltaic 
nt tracking techniques," IEEE 
GY CONVERSION EC, vol. 22, 
photovoltaic systems maximum 
Texas Instruments Rapport 
mber, vol. 2010, 2010. 
mparison of the performance of 
king schemes applied to single-
voltaic systems," IET Electric 
p. 753-762, 2007. 
"Modified Perturb and Observe 
ft Avoidance in Photovoltaic 
s on Industrial Electronics, vol. 
S. Leva, "Energy comparison of 
for PV systems," Journal of 
d Applications, 2009. 
assoud, S. Ahmed, and P. Enjeti, 
e perturb and observe MPPT 
aic-based microgrids," IEEE 
tronics, vol. 26, pp. 1010-1021, 
, M. Amran, A. C. Soh, and N. 
aptive perturb and observe-fuzzy 
nt tracking for photovoltaic boost 
Power Generation, IET, vol. 8, 
paio, G. Luigi, and C. Canesin, 
MPPT techniques for PV 
ional Conference on Clean 
011 2011, pp. 99-104. 
 and S. Duan, "Comparison of 
T methods for grid-connected PV 
ference on Industrial Electronics 
A 2008. , 2008, pp. 804-807. 
258