Post on 05-Apr-2018
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SEMINAR REPORTON
MICROPOWERSYSTEMS
Submitted by:
SOURAV KANJILAL7th Semester
Electrical Engineering
0301101192
UCE, Burla
DEPARTMENT OF ELECTRICAL ENGINEERING
UNIVERSITY COLLEGE OF ENGINEERING, BURLA
Dist: SAMBALPUR, ORISSA-768018
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CERTIFICATE
This is to certify thatSOURAV KANJILALbearing Roll No. 0301101192,
student of 7th semester Electrical Engineering Branch, University College of
Engineering, Burla has delivered his seminar talk on MICROPOWER
SYSTEMS ON 18TH
AUGUST 2006.
Prof. B.B. Pati Prof. B.B. Pati
Head of Department Teacher in ChargeDepartment Of Electrical Engineering
University College Of Engineering, Burla
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ACKNOWLEDGMENT
In presenting my seminar on MICROPOWER SYSTEMS I am grea
indebted to Prof. Dr. B.B. Pati for providing an insight into the topic, buildi
my concepts and providing some of the precious inputs and guidance for m
paper.
I am grateful to faculty members of my branch for bringing out t
inquisitiveness within me to deliver a seminar about this topic, sorting out m
loopholes and for their kind cooperation and advices.
I am also very grateful to the laboratory teachers for helping me in developi
a practical viewpoint to my topic.
Finally, I would like to thank my peers for sufficing me with some hard fou
materials. Moreover, my interaction with them helped me to have a mu
clearer understanding of the topic.
SOURAV KANJILAL
7th Semester
Electrical Engineering0301101192
UCE, Burla
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CONTENTS:
1. Introduction
2. What is MicroPower System??
3. Why MicroPower??
4. Energy Scavenging Areas
5. Energy Reservoir Systems
6. Conclusion
7. References
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INTRODUCTION
The present scenario of power generation all over the world though not dismal, bu
is in an alarming stage. Even the countries those boasts of huge resources of fossil
fuels like coal, oil, etc. have begun twitching their eyebrows. There is a mostprobability of huge increase in demand of power in the next few decades, most of
which will be from developing countries where most areas are still not accessible to
electricity.
In such a case, we dont even realize the huge amount of energy we are wasting o
the energy which though small, but can be harvested to an extent to powering a
household or a small office. Though small or even distributed, there are some ways t
scavenge the wasted energy and utilize them for beneficial purposes. These systems MicroPower Systems.
These systems are under extensive research and utilization in the Western countri
and are extending towards the Orientals and soon the entire world will be under the
spell of these extremely small techniques called MicroPower Systems.
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WHAT IS MICROPOWER SYSTEM??
Generation of small amounts of electricity from basically abstractsources close to where it is used is termed as MicroPower.
This eliminates the need for both excess production by the traditional
generating stations powered by coal, oil or nuclear power, and
transmission grids to deliver that power.
DRIVING FORCES FOR MPS
With passing time, man has developed a
lot and so his power demands have become
ever increasing.
The worldwide demand for energy isexpected to grow by 50% over the
next 20 years. A lot of this increased
demand will come from developing
countries where two billion people
do not have access to electricity.
Micro power can help meet this demand
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WHY MICROPOWER??
1. We get renewable, on-site energy and thus reduces green house gasemissions as compared to its bigger cousins like thermal or nuclear
plants.
2. The MicroPower advocates dont plan to replace the traditional
electrical grid. In fact, this acts one of the greatest advantages: the abili
to feed unused electricity from micro generators back into the main grid
supplementing the supply of energy from traditional sources.
3. "Interconnection" represents micro power's greatest promise and th
provide reliable service in remote communities as well (i.e. which are
away from the normal supply lines).
4. The most exciting concept of MPS is waste energy scavenging concept
i.e. deriving the energy from energy which is wasted away.
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ENERGY SCAVENGING AREAS
1. Solar/Ambient Light
2. Temperature Gradients
3. Human Power
4. Air Flow
5. Pressure Gradients
6. Vibrations
The various energy-scavenging schemes depend upon the existing physical
and environmental conditions.
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SOLAR and AMBIENT LIGHT
Sources:
Noon on a sunny day: 100 mW/cm2
Office Lights: 7.2 mW/cm2
Collectors:
SC Silicon
15% - 30% efficient
Poly-Silicon
10% - 15% efficient
Solar Powered Pico Radio Node Photoelectric Dyes
(size comparable to a coin) 5% to 10% efficient
Solar energy can be harnessed by Solar Photo
Voltaic Cells (made of Si) i.e. the directconversion of solar to electrical energy.
Light Energy Excites the Si electrons out of their
atoms, which are then captured by the wires
embedded in the system
Flow of electrons
Current
A group of PV Cells= PV module,
The capacity of which varies from small to
a limit of 300W.
A Group of PV modules = PV arrays
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which can be mounted on rooftops for generation.
There are currently about 300,000 PV installations connected to the electrical grid
Worldwide.
TEMPERATURE GRADIENTS
Exploit gradients due to
waste heat / ambient temp
Maximum power = Carnot efficiency
10C differential = (308K 298K) /308 = 3.2%
Through silicon this can be up to 110 mW/cm2
Methods
Thermoelectric (Seebeck effect) ~ 40W/cm2 @ 10C PiezoThermo Engine
Piezo thermo engine ~ 1 mW/mm2(theoretical)
Seebeck Effect is the phenomenon by whichthe temperature difference
across the ends of any thermo-electric material is transformed into electricity
The temperature difference created due change in orientation of electrons
in a piezoelectric material leads to small amount of electricity which can
be harnessed.
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HUMAN POWER
Burning 10.5 MJ a day
Average power dissipation of 121 W
Areas of Exploitation
Foot
Using energy absorbed by shoe when stepping
330 W/cm2 obtained through MIT study
Skin
Temperature gradients, up to 15C
Blood
Panasonic, Japan demonstrated
electrochemically converting glucose
The above figure depicts a flexible wireless
sensor module attached to this bracelet and
powered by the thermoelectric generator .
Thermal energy scavengers use Seebeck effectto transform the temperature difference
between the environment and the human
body into electricity.
At the heart of this Thermoelectric generator, there are about
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3000 Bismuth Telluride blocks.
The capacity of the Thermoelectric generator is about 150W
However, this can be complicated by low temperature difference between
the body and the thermoelectric blocks.
AIR FLOW
Power output/ efficiencies of the turbines vary
with velocity and motors
Applications dont need continuous and huge
force of strong wind. It can be implemented
where average air flow is of the
order of 5 m/s
For a motor of around 100% efficiency
~1 mW can be generated
MEMS turbines may be used to compose Micro turbines, which are used to
Harness even slightest amount of breeze into electricity.
MEMSMicro Electro Mechanical System, i.e. small transducers integrated
Si chips to transform into Electrical energy.
The Micro turbines are connected to a Stop Switch (regulate the inflow of current)
These are in turn connected to a Charge Controller, which connect a Battery-Bank
and a sine-wave inverter to convert to convert into AC. The output of this is either
connected for household applications or tied to the grid.
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PRESSURE GRADIENTS
Using ambient pressure variations
On a given day, for a change of .2 inches Hg,
density on the order of nW/cm3
Manipulating the temperature conditions:
Using 1 cm3 of helium, assuming 10C
and ideal gas behavior, we can harness ~ W/cm3
No active research on pressure gradient manipulation is currently in
progress as the amount of power produced is quite less and thus is
not economical to be harnessed.
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VIBRATIONS
The basic concept used to harness the
effect of vibrations is application of
Piezo Electricity.
This is based on the concept of change
in the electrical-domains of a piezoelectri
substance due to application of pressure.
It is direction sensitive and thus the
electricity produced is alternating innature.
Sources:
Motors / Engines
Existing Designs:Roundy design, with the capability of ~ 800W/cm3
at 5m/s2.
Future Plans:
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# MEMS Piezo
# MEMS Capacitance
Both the structures are dependant on Si based
transducers.
ENERGY RESERVOIRS
1. Batteries
2. Fuel Cells
3. Capacitors
4. Heat Engines
5. Radioactive Sources
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BATTERIES
They are closed systems (except Zinc air) in which the area of the electrodes
determines the power and the volume of electrodes of the electrodes determines
the capacity of the battery.
They can be classified into 2 categories:
(I) Macro Batteries
Micro Batteries
Macro Batteries includeZinc air (3500 J/cm3), Alkaline (1800 J/cm3) and
Lithium (1000 - 2880 J/cm3)
They are comparatively bigger in size and are generally used for medium or
high power portable devices.
Micro Batteries, which are in the pipeline include:
Lithium
(i) Thin film Li (1-D micro scale, 2-D macro scale)
(ii) 3-D Lithium Ion (in initial stages)
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Ni/ NaOH /Zn
(low potentials)
For a 3-D Lithium Ion cell,
Anode : Pyrolyzed Carbon (graphite)
Cathode : Aero gel (Sol-Gel processed) V2O5.
Electrolyte : Spin On PEO
3-D Lithium Ion Cell
MEMS FUEL CELL
Fuel cell basics include the production
of H2 by hydrolysis of H2O and thencombination with O2 to produce
electricity and only water vapour
as by-products.
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The presently existing techniques are: Current Generation
Toshiba 1 cm3 hydrogen reactor
Produces 1watt
Next Generation
Planar Arrays
Fraunhofer = 100 mW/cm2
Stanford = greater than 40 mW/cm2
(more room for improvement)
(more scope for improvement)
The fuel cells are stackable and thus can be utilized for even more capacities.
CAPACITORS
They are useful for on-chip power conversions.
They can also be used for secondary storage for frequent but non-periodic
energy sources
Energy density is actually too low to be real general secondary storage compone
Due some of these lacunas, Ultra-Capacitors are also used as storage devices
They have different surface area w.
capacitors and have highly porouselectrodes
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They have acceptable potential for secondary storage but we do face issues like :
Size
Leakage
Distribution of Pores
The Energy Density is of the order of 75kJ/cm3.
Continuous R&D is in progress to shrink the size of these Ultra-Capacitors.
MICRO HEAT ENGINES
MEMS scale parts for meso
small-scale engine
1 cm3 volume
13.9 W
They possess poor transient
properties
Micro size heat engine
ICEs, thermoelectrics,
thermoionics, thermophoto voltaics via controlled
combustion
Meant for micro scale
applications with high
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power needs
RADIOACTIVES APPROACHES!!
They demonstrate high theoretical energy density
The Power density of such elements is inversely proportional to the
half life of the radioactive material.
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The demonstrated power is in the order of nanowatts only (reactor-less)
They are generally avoided because of the increasing environmental concern
regarding the disposal of the radioactive wastes.
CONCLUSIONWith the increasing crisis for electrical energy and alarmingly depleting level of fossil
fuels, there is a need to create a new way to obtain energy at least enough for utilization
a small household or office by distributed generation.
For this purpose continuous R&D is on for high quality and competitive power.
Even research is on for EMPS (Emergency Micro Power Systems) i.e. supply of powerduring emergency conditions like load shedding. These facilities are already in use in
various hospitals, banks, restaurants, etc.
The ongoing work and active research is steaming ahead and will continue until we hav
squeezed in every wasted kilowatt-hour or leaking calorie of heat out of our homes and
businesses
And succeed in making
MICROPOWER: THE NEXT ELECTRICAL ERA
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REFERENCES
1. terrain.org
2. powerconnect.com
3. micropower-connect.org
4. the-infoshop.com