power electronics applications in power systems

1. Simulation of Maximum Power
Point Tracking for Photovoltaic
Systems

2. Abstract:
 A photovoltaic (PV) solar panels exhibit non-linear current–
voltage characteristics, and according to the maximum power
transform (MPT) theory, it can produce maximum power at
only one particular operating point (OP), namely, when the
source impedance matches with the load impedance, a match
which cannot be guaranteed spontaneously. Furthermore, the
maximum power point (MPP) changes with temperature and
light intensity variations. Therefore, different algorithms have
been developed for maximum power point tracking (MPPT)
based on offline and online methods. Evaluating the
performance of these algorithms for various PV systems
operating under highly dynamic environments are essentials to
ensure a reliable, efficient, cost-effective, and high
performance systems.

3. CONTENTS
 PROBLEM DESCRIPTION
 PROBLEM SOLUTION
 BLOCK DIAGRAM OF DESIGN MODEL
 BLOCK DIAGRAM OF ANALYTICAL MODEL
 SCHEMATIC DIAGRAM OF PV SYSTEM
 PV SYSTEM MODEL
 DEFINITION OF MPPT
 DESCRIPTION OF MPPT
 ADVANTAGES
 REFERENCES

4. PROBLEM DEFINITION:
 The development of renewable energy has been an
increasingly critical topic, due to the tremendous growth in
energy demand that is expected to climb 35% by 2030 in
comparison with current energy consumption.
 As a result of that an enormous pressure on existing
conventional energy resources, in particular, fossil fuels such
as oil and natural gas.
 Where they are currently providing more than 98% of the
energy consumed worldwide .
 Dependence on fossil fuels presents a number of challenges,
including: high cost, environmental damage, and lack of
sustainability.

5. PROBLEM SOLUTION:
 The most obvious source of RE is the solar energy.
 A photovoltaic (PV) solar panels exhibit non-linear
current–voltage characteristics, and according to the
maximum power transform (MPT) theory, it can
produce maximum power at only one particular
operating point (OP), namely, when the source
impedance matches with the load impedance, a match
which cannot be guaranteed spontaneously.

6. The role of simulation in validating a design model.

7. The role of simulation in validating an analytical model.

8. Schematic diagram of a PV system.

9. PV SYSTEM MODEL
 A general configuration of a standard PV system
comprises the following components:
 A standalone PV panel
 An MPPT composed of a DC-DC converter
topology along with its MPPT algorithm. An
inverter can be used when AC load is needed.
 A battery bank as a storage device with its
associated charger controllers.

10. Definition of MPPT(maximum power point tracking)
 There is a need to implement an MPPT algorithm to
track changes and extract the maximum power from
the PV solar panel, because the power generated by
the panel is significantly affected by variations in
irradiation, temperature and panel voltage, revealing
a non-linear characteristic.
 An MPPT system can be defined as an electronic
device that operates the PV panel in such way that it
delivers all the power it can produce.

11. Contd………..
 The difference between MPPT system and a mechanical
tracking system is that the mechanical system physically
orients the panel straight at the sun, while the MPPT
system electronically control the system so it can change
the electrical OP of the panel in accordance with changes
in irradiation or temperature, so that the solar panel is
able to yield the maximum available power.
 The MPPT plays the role of impedance matching adapter,
i.e., it forces the impedance at the terminals of the PV
panel to the value that produces maximum power out of
the panel.

12. ROLE OF MPPT IN PV SYSTEM
 MPPT plays a big role in PV systems because it
maximize the power output from a PV system for a
given set of environment changes and load
variations, and therefore maximize the array
efficiency and minimize the overall system cost.
 The MPP varies depending on the irradiation and
cell temperature, therefore; appropriate algorithms
must be developed to track the MPP and maintain
the operation of the system as close as possible to
this point.

13. Description of MPPT
 Typical solar panel can only convert 30% to 40% of the
incident solar irradiation into electrical energy. However,
usually solar panel delivers less than that, because according
to the MPT theorem, the actual power output of a circuit
reaches its maximum when the source impedance matches
with the load impedance, a match which is usually not
guaranteed.
 MPPT algorithms are used to ensure impedance match to
improve the efficiency of the solar panel in delivering its
maximum power.
 In the source side a boost converter is connected to a solar
panel in order to enhance the output voltage. By changing the
duty cycle of the boost converter appropriately the source
impedance is matched with that of the load impedance.

14. Perturb and Observe (P&O) algorithm
 The P&O algorithm is used due to its simplicity and easy
implementation.
 The operation of P&O consists in periodically perturbing
the panel operating voltage incrementally, so that the
power output can be observed and compared at
consecutive perturbing cycles.
 If the power difference is positive, further perturbation is
added to the operating voltage with the same increment,
and again the output power is observed. This perturbing
process is continued until the power difference becomes
negative.
 Thus, the direction of perturbation in operating voltage
must be reversed.

15. Advantages:
 The most obvious source of RE is the solar energy,
therefore, a huge number of projects and
researches have been adopted worldwide to utilize
the indispensable sunlight as a sustainable source
of energy.
 PV solar cells have relatively low efficiency ratings;
thus operating at the MPP is desired because it is
at this point array will operate at the highest
efficiency.

16. CONCLUSIONS
 A MPPT controller for PV solar system is modeled in this
project using the P&O algorithm on MATLAB software.
 The simulated model demonstrated an excellent and
flexible environment for studying various PV solar cells
operating under different environments of irradiance
and temperature.
 Many other parameters can be modeled and investigated
using the same model which all left for future research.
 Furthermore, the same simulation approach can be
equally applied to other renewable energy sources, such
as the wind energy system.

17. REFERENCES
 [1] National Renewable Energy Laboratory and the
Department of Energy, “Types of renewable energy”, accessed
on 20th April 2013 from
http://www.renewableenergyworld.com/rea/tech/home .
 [2] US Energy Information Administration, “Energy
consumption by primary fuel”, accessed on 2nd April 2013
from http://www.eia.gov/forecasts/aeo/er/early_fuel.cfm.
 [3] Internationa Energy Agency, “Tracking clean energy
progress 2013”, accessed on 2nd May 2013 from
www.iea.org/publications/tcep_web.pdf
 [4] C. Hua and C. Shen, “Comparative study of peak power
tracking techniques for solar storage system”, Proceedings of
the 13th Annual Conference on Applied Power Electronics
Conference and Exposition (APEC '98). Vol. 2, pp. 679 – 685,
1998.