DESIGN OF A HYBRID ENERGY POWER SYSTEM USING SOLAR AND WIND POWER

Abstract

There is increasing demand for the use of alternative renewable energy sources to achieve clean and low-cost electric energy for loads. Wind and solar energies are some of the renewable energy sources which are mostly available in the world. In this study, a hybrid power station has been designed using solar and wind energies.

Full text

Page 1

DESIGN OF A HYBRID ENERGY POWER SYSTEM USING SOLAR AND
WIND POWER
İlhami Çolak Ramazan Bayındır İbrahim Sefa Mehmet Demirtaş
Gazi Üniversitesi, Teknik Eğitim Fakültesi,Elektrik Eğitimi Bölümü, Ankara, TÜRKİYE
icolak@gazi.edu.tr bayindir@gazi.edu.tr isefa@gazi.edu.tr mehmetd@gazi.edu.tr
Keywords: Solar energy, wind energy, renewable energy sources, utility interactive inverter


ABSTRACT
There is increasing demand for the use of alternative
renewable energy sources to achieve clean and low-cost
electric energy for loads. Wind and solar energies are
some of the renewable energy sources which are mostly
available in the world. In this study, a hybrid power
station has been designed using solar and wind energies.
I. INTRODUCTION
The amount of energy sources such as gas, water, coal
and petrol are being reduced day by day since they are
used in industry intensively. On the other hand, the need
of electrical energy is increasing in parallel with
developing technology. Electrical energy can be produced
using energies of water, coal, petrol and gas. But, the
price of the electrical energy is increasing due to lack of
energy sources mentioned above. In addition, coal, gas
and petrol can cause air pollutions when they are burned
to produce energy.
There are other energy sources that can be used for
production of electrical energy. Wind and solar (W&S)
energies are some of them. These are renewable energy
sources as well as environment friendly, cheap and
mostly available in the world.
The use of wind energy for production of electrical
energy was started in 19th century in the world. Studies
about the production of electrical energy from solar
energy were started in 1954. These studies were increased
after the petrol crises in 1974.
Studies about the systems use renewable energy sources
such as solar, wind, geothermal, biomass (Wood and
Charcoal), and water are being continued. A hybrid
wind/photovoltaic system has been developed recently
and studies about it are still being carried on. Wind and
solar are very important renewable energy sources for
these kinds of applications [1-3]. Double-input single-
output converters as parts of hybrid system were also
discussed in these papers. Steady-state performance of a
grid-connected roof-top hybrid wind/photovoltaic power
system with battery storage was studied in reference [4].
Developments in micro controller and semi-conductor
technologies have increased the studies about the hybrid
systems running in parallel with the grid [1-4].
Residential photo-voltaic grid-connected inverters are
modular distributed power generation devices that
convert the direct current (DC) power from the roof-top
solar panels to high-quality alternating current (AC)
power at the utility grid interface [5].
In this study, a hybrid power station has been designed
using W&S energy. The obtained energy from W&S is
given to the loads first, and then stored in the batteries.
When the batteries are fully charged, it is directly
transferred to the power grid. This will enable the power
to flow in both directions between the power station and
the power grid. If there is no energy produced by the
system or stored in the batteries, the load of the system is
fed from the power grid. Proposed hybrid system
produces cheap, clean and environmental friendly electric
energy and therefore is very important for countries
which are very rich in S&W energy sources.
II. THE CONFIGURATION W&S SYSTEM
Hybrid power station has been designed using W&S
energy. The W&S system configured in Fig. 1 is
composed of following;

Page 2

•
•
•
•
•
•
Low-speed, multi pole alternator
DC/AC inverter
DC/DC converter
Charging units
Pillar and mechanism of wind turbine
Sun tracking system for solar cell
A. Producing of Solar Energy
Solar panels can be connected in parallel or in serial to
obtain required power by load. But, the power obtained
by this way is DC and it should be converted into AC for
some loads. Therefore, a DC to AC converter is required.
Electrical energy is not only required during day time, but
it is needed at nights as well. This requirement put
forwards the use of other renewable energy sources, such
as wind energy, available during the night.
B. Producing of Wind Energy
The wind power stations can be a few hundred watts to a
few megawatts. These power stations are not sufficient to
feed a house all times during a day. If the power of a
wind power station is over 1 kW, its price goes up to very
high values. On the other hand, to store wind energy, a
group of batteries has to be connected to output of the
alternators. Therefore, a rectifier is also required to
convert AC voltage produced by alternator, to DC
voltage.
C. Producing of W&S Energy
In a hybrid energy power system, W&S are used as main
energy sources connected in parallel with the grid. In the
proposed system, if electrical energy is not used by the
load during either day time or at night, the electrical
energy produced can be stored in batteries and then can
be used when there is no W&S to produced energy for the
load. Lives of the batteries used are very short compared
with other equipment in production system. Therefore
batteries have to be used rarely. The most important
criteria for the life of batteries are the number of charge
and discharge. The less they operate the more they live.
Even tough the system has W&S energy source system,
the load can still be without energy if there is no W&S
and stored energy. At this time, the load can be fed from
the grid.
Running of the proposed system in parallel with the grid
reduces the price of the electrical production and the
support of the diesel engines and the batteries. The
produced electrical energy can be send to the grid when
there is no load requiring energy on the system. That
means, the produced energy is sold to grid and the cost of
the whole system is reduced. In addition, while producing
electrical energy from both W&S and either of them,
there is nothing used to increase the cost of the
production such as gas, petrol and coal. Therefore, selling
of the produced energy to grid is the benefit of the
system. The money gained by this way can later be used
for both maintenance of the system and buying electrical
energy from the grid when it is not possible to produce
energy from W&S for some reason.
The study starts choosing a sunny and windy place, in
where a real load is also provided. Then, mechanical parts
of the solar panels and wind turbines are prepared and
constructed on a chosen place. After that, energy
production and storing circuits and related equipment are
prepared. Finally, all the system is joined together.
III. DESIGN OF A PROTOTYPE
In this study, all the work is done in a sequence. First of
all, field survey is done collecting necessary data about
the wind and sun daily, monthly and yearly. Then, a
suitable place for establishing the solar panel and wind
turbine is chosen.
Secondly, a real load for the system is connected to
system to get the exact data during the study. AC voltage
obtained from wind turbines are converted to DC voltage
through a bridge rectifier and Boost converter as given in
Fig. 1. DC voltages obtained from solar panels and wind
turbines are collected on the DC bar, where the level of
the DC voltage is kept constant. Software for these
purposes is written by the authors using a microcontroller.
Battery groups connected to both DC bar and grid are
charged under the control of microcontroller. Then, DC
energy coming from battery groups and Boost converter
are inverted to AC energy through an inverter to feed the
load. If all the batteries are fully charged and the
produced energy is higher than the requirements of local
loads, extra energy produced is sold to grid. Operations of
the system and values of current, voltage, power and load
are recorded in a file daily, monthly and yearly to analyse
them when required. Priority is given to charge batteries
and to feed local loads. The amount of stored energy and
the back up time of it according to load are calculated and
required information is given to user.

Page 3

Wind Turbine
DC
AC
G
c
d
a
b
Solar
Panels
Batteries
Micro
Controller
f
e
Charge
Unit
a
c
e
f
g
h
b
d
kWh
1
kWh
1
kWh
1
Load
Grid
h
g
a. Wind turbine current transducer
b. Boast converter1 trigger signal
c. Solar panels current transducer
d. Boast converter2 trigger signal
e. Battery group current transducer
f. Inverter entry current transducer
g. Load current transducer
h. Grid current transducer
1-Electric meters
2- Power switch
3-Diode
4-Coil
5-Capacitor
6-IGBT
7-Tyristor
8-Inverter
2
3
3
34
4
5
5
6
6
7
8

Fig. 1. Block diagram of a hybrid power system using W&S energies
IV. CONLUSION
The hybrid system proposed in this study is suitable for
small houses. In the system, electrical energy is produced
from either solar panels and/or wind turbines. Then it is
directly given to the load first. If the load is not required
electrical energy, then it is given to the battery groups to
charge them. If batteries are fully charged, then the
produced energy is sold to grid to gain money to reduce
the expenses of the whole system. In the system, the
charge unit, wind turbine, solar panels, batteries, rectifier,
converter, inverter, load and electric meters are controlled
by microcontroller using the written software. The aim of
the present study is to start the microcontroller controlled
hybrid energy production in Turkey, which is very rich in
W&S energy sources.
V. REFERENCES
[1] Borowy B.S., Salameh Z.M. “Optimum Photovoltaic
Array Size for A Hybrid Wind/PV System” IEEE
Trans. On Energy Conv., Sept 1994, Vol 9, pp. 482-
488.
[2] Crescimbini F., Carricchi F., Solero L., Chalmers
B.J., Spooner E., Wei W. “Electrical Equipment for
A Combined Wind/PV Isolated Generating System”,
IEE Opportunities and Advances in International
Power Generation Conference, 18-20 March 1996,
No. 419, pp. 59-64.
[3] Solero L., Carricchi F., Crescimbini F., Honorati O.,
Mezzetti F. “Performance of A 10 kW Power
Electronic Interface for Combined Wind/PV Isolated
Generating System”, IEEE Trans. On Energy Conv.,
1996, pp1027-1032.
[4] Giraud F., Salameh Z.M. “Steady-State Performance
of A Grid-Connected Rooftop Hybrid Wind-
Photovoltaic power System with Battery Storage”,
IEEE Trans. On Energy Conv., March 2001, Vol 16,
pp. 1-7.
[5] Wang X., Kezerani M. “A Modular Photovoltaic
Grid-Connected Inverter Based on Phase-Shifted-
Carrier Technique”, IEEE Trans. On Energy Conv.,
2002, pp. 2520-2525.
[6] Hepbasli A., Ozgener O. “A Review on the
Development of Wind Energy in Turkey”, Renewable
and Sustainable Energy Reviews, 2004, 8, pp. 257-
276.
[7] Hanağasıoğlu M. “Wind Energy in Turkey”,
Renewable Energy 1999,16, pp. 822-827.

Page 4

[8] Öztopal A., Şahin A.D., Akgün N., Şen Z. “On The
Regional Wind Energy Potential of Turkey”,
Energy, 2000, 25, pp.189-200.
[9] Şen Z.”Areal Assesment of Wind Speed and
Topography with Application
Renewable Energy, 2001, 24, pp. 113-129.
in Turkey”,
[10] Kaygusuz K., Sarı A. “Renewable Energy Potential
and Utilization in Turkey”, Energy Conversion and
Management, 2003, 44, pp. 459-478.
[11] Oğulata R.T. “Energy Sector and Wind Energy
Potential in Turkey”, Renewable and sustainable
Energy Reviews, 2003, 7, pp. 469-484.
[12] Evrendilek F., Ertekin C.“Assesing The Potential of
Renewable Energy Sources in Turkey“, Renewable
Energy, 2003, 28, pp. 2303-2315.
[13] Özdamar A., Gürsel K.T., Orer G., Pekbey Y.
“Investigation of The Potential of Wind- Wawes as
A Renewable Energy Resource: By The Example of
Çeşme-Turkey“, Renewable and sustainable Energy
Reviews, 2004.
[14] Köse R. “An Evaluation of Wind Energy Potential
as A Power Generation Source in Kütahya, Turkey”,
Energy Conversion and Management, 2004, 45, pp.
1631-1641.
[15] Akpınar E.K., Akpınar S. “Determination of the
Wind Energy Potential for Maden-Elazig, Turkey”
Energy Conversion and Management, 2004.
[16] Ozerdem B., Turkeli M. ”An Investigation of Wind
Characteristic on The Campus of Izmir Institute of
Technology, Turkey” Renewable Energy, 2003, 28,
pp.1013-1027.
[17] Aras H. “Wind energy status and Its Assessment in
Turkey”, Renewable Energy, 2003, 28, pp.2213-
2220.
[18] Ocak M., Ocak Z., Bilgen S., Keleş S., Kaygusuz K.
“Energy Utilization, Environmental Pollution and
Renewable Energy Sources in Turkey”, Energy
Conversion and Management, 2004, 45, pp. 845-
864.