Maximum power point tracking techniques introducing the mppt tracking technique for a solar cell device

1. Maximum power point
Tracking Techniques for
Photovoltaic systems
Hadeer Abdelaziz
hadeerali127@outlook.com

2. Outline
●PV Cells Power converter
challenges and opportunities
●VI Characteristics of PV Cell
●Different MPPT Techniques
●Results

3. PV cells power converter
challenges & opportunities
● (PV) systems feature booming interest in
current decade.
● MPPT of PV cell output power is mandatory
to improve output power generation and
reduce cost.
● The obstacles of these systems are its non-
linearity as environmental conditions
change and the conversion efficiency is low
● Researches all over the world do many
researches in the field of MPPT for PV cells

4. VI Characteristics of PV cell
● Non-linear relationship between voltage
and current can be expressed in figure 1,
equation 1
Fig.1 Electrical equivalent circuit
of PV cell
I denotes a current of a solar array (A).
V denotes an output voltage of a solar array(V).
Iph denotes the light generated current (A).
Isat denotes a diode reverse saturation current
(A).
k is Boltzmann’s constant.
Rs denotes a series resistance (Ω).
and Rsh denotes a shunt resistance (Ω).

5. Different MPPT techniques
● Perturb and Observe (P&O)
● Sample/Hold
● Exponential Locking
● Digital Locking
● ANN

6. Perturb and Observe (P&O)
● Periodically , monitor the
amount of power incoming
from DC/DC converter
● Adjusting the appropriate
signal for system to work on
MPP
● Change switching frequency
to operate around MPP
● Figure 2 shows divergence
of calculation for system for
different environmental
irradiance
For one period, If the
irradiance increases the
curve shifts from P1 to
P2 ➔ the operating
point shifts from A to c

7. Sample/Hold
● Depending on the chemical property of
PV cells ➔ the Vmpp ≈ k. Voc
● K ranges from 0.6 to 0.8
● Periodically samples the Voc of the PV
cell over 24 hours for different conditions
● Decide an appropriate sampling rate and
also sampling frequency

8. Exponential Locking algorithm
● locks in the maximum power of PV cell
around a large range of irradiance light.
● Analytical derivations of system
equations
● Exponential relationship between PV
terminal voltage & output voltage of DC
converter
● The main advantage of this technique is
no need for sensing current
● Generating appropriate frequency of
the system
● fclk = f(Vmpp)
● Figure 4 shows block diagram of the
system
Fig.4 Block diagram of the
system

9. Digital Locking algorithm
● The relationship between charge pump
optimum frequency locking and the solar
cell voltage has an exponential nature.
● The exponential relation is linearized by
dividing the allowed range of VMPP into
different intervals it converted to arithmetic
operation .
● The function is implemented using Verilog
and synthesized on synopsis in order to
evaluate the implementation area and
power consumption

10. ANN Technique
● ANN is an arithmetical modelling of human
neural network by programming.
● This technique solves the problem of
nonlinearity of PV system by training the
system more & more to produce the
optimal voltage for MPP under various
conditions
● The error then feed backed to the NN ,
trained again , until actual voltage
approaches the optimal voltage

11. ● The ANN tracks the optimal voltage as
compared to P&O method.
● Lower oscillation of the system
● Figure 5 shows the block diagram of the
system
Fig.5 Block diagram of ANN MPPT control unit

12. Results
MPPT
Technique
PV cell
dependant
True MPPT? Complexity Sensed
parameters
P&O No Yes Low V,I
Sample/Hold Yes No Low V
Exp.Locking No Yes complex V
Digital
Locking
No Yes complex V
ANN No Yes Low V

13. References
● [1] Hui Shao, Chi-Ying Tsui, Wing-Hung Ki, "The Design of a Micro Power Management System for Applications
UsingPhotovoltaic Cells With the Maximum Output Power Control ",IEEE TRANSACTIONS ON VERY LARGE SCALE
INTEGRATION (VLSI) SYSTEMS, VOL. 17, NO. 8, AUGUST 2009
● [2] Alex S. Weddell, Geoff V. Merrett, Bashir M. Al-Hashimi," Ultra Low-Power Photovoltaic MPPT Technique for
Indoor and Outdoor Wireless Sensor Nodes",School of Electronics and Computer Science, University of Southampton,
SO17 1BJ, UK{asw,gvm,bmah}@ecs.soton.ac.uk
● [3] Ayman Eltaliawy, Hassan Mostafa , Yehea Ismail," Microscale Solar Energy Harvesting for Wireless Sensor
Networks Based on exponential Maximum power Locking Technique", Elsevier Microelectronics Journal, Vol. 46, No. 3,
pp. 221-230,2015
● [4] Ayman Eltaliawy, Hassan Mostafa , Yehea Ismail," A New Digital Locking MPPT Control for Ultra Low Power Energy
Harvesting Systems ", 978-1-4799-8893-8/15/$31.00 2015 IEEE
● [5] zhoa long , Liu liqun ,"The MPPT control method by using BP neural network in PV generation system " , 978-0-
7695-4792-3/12 $26.00 © 2012 IEEE DOI 10.1109/ICICEE.2012.433

14. Thank
You