Microprocessor System

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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

Documents

Microprocessor System