Transcript Energy Harvesting - IEEE Real World Engineering Projects

Energy Scavenging
from Vibrations
– Summary Lecture
Problem Review
Energy Harvesting
• Wind
• Water
• Solar
• Temperature
• Vibration
Energy Scavenging through
Vibration
Piezoelectric
Piezoelectricity is the ability
of certain materials to
produce a voltage when
subjected to mechanical
stress.
Piezoelectric materials also
show the opposite effect,
where application of an
electrical field creates
mechanical stress (size
modification) in the crystal.
Piezoelectric Frequency Response
Components Provided
Methods for Solving the Problem
Rotary-to-Reciprocating Motion
Continuous rotary motion can be generated using motors.
Conversion between rotary motion to reciprocating motion
can be achieved using an asymmetric cam .
Rectifying Circuit
A rectifier circuit can be used to convert an AC electric
signal to a DC signal.
A four diode bridge can be used as a rectifier.
Capacitor
A capacitor is a device that can store electrical charge.
In a capacitor equal amounts of positive and negative
charges are stored on two separate conductors.
Charging Circuit
A super capacitor (0.47F 5.5v) is used to store electric
charge.
A Zener diode (BZX85-C5V6) is used to protect the
super capacitor .
Engineering Principles and
Concepts
DC Motor (Speed vs. Voltage)
The induced force (F) is
perpendicular to the direction
of the current (I) and of the
electromagnetic flux (B).
F  B I
V  RI  e  RI  Ke
V
R
e
The speed of the motor is
approximately proportional
to the input voltage.
Gear Ratio
A
B
driven
driving
 A TB
G

 B TA
Gear Train
Simple gear train
A
B
Compound gear train
C
A
B
D
C
driving
idler
 A TC
G

C TA
driven
 A TB TD
G

 D TA TC
AC vs. DC
In alternating current (AC)
the movement (or flow) of
electric charge periodically
reverses direction.
In direct current (DC) the
movement of electric
charge doesn’t change
direction.
Diode
Diodes allow the electric
current to flow in only one
direction.
+
v
i
i
v
4 Diode Bridge
The Meaning of Frequency
Frequency means the number of times something occurs
within a given time period. Frequency for waves is usually
measured per second. The unit for frequency is Hertz (Hz),
which means per second.
Spectrum Decomposition
Design Trade-offs
Two types of testing stations that generate vibrations
for the piezo buzzer are designed, with/without a
gearbox .
The gearbox provides the flexibility to tune the
vibration frequency to match the resonant frequency
of the piezo buzzer.
The more complex the design is, the longer the
time and higher the costs it takes to implement it,
but the more chance that it should provide better
results.
Engineering Design Process
Identify the need
or problem
Modify to improve
the design if needed
Test and evaluate
the prototype
Construct a
prototype
Research the
need or problem
Develop possible
solutions
Select the best
solutions
Design of a Lateral
1
Saddle
1. Gathering information
2. Identify constraints and design variables
3. Preliminary design
1
Freshman Engineering Project. Department of Civil and Environmental Engineering. Polytechnic University of
Puerto Rico
Design of Lateral Saddle (cont.)
4. Evaluation and selection of preferred solution
5. Preparation of plan and specification
6. Implementation of the design
7. Test and evaluation
Reflective Problem Solving
Strategies
define the problem
Test, evaluate,
and improve
the design
analyze the problem
reflect
identify design variables
propose solutions
Implement the design
Societal Impact
Energy harvesting or the process of acquiring energy
from the surrounding environment has been a
continuous human endeavor throughout history.
Societal Impact
Piezoelectric materials, such as the lead zirconate
titanate (PZT), are great candidates for energy
harvesting using vibrations from the surrounding
environment.
Application Areas
Wireless corrosion monitoring
systems
vibrating structure
mechanical energy
Accel. PSD
vehicle
frequency
Self-powered Wireless Corrosion Sensor
energy harvester
corrosion sensor
low power
wireless transceiver
Biomechanical Energy
Harvester
References
1.
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5.
6.
M. Raju, “Energy Harvesting, ULP meets energy harvesting: A game-changing
combination for design engineers,” Texas Instrument White Paper, Nov. 2008
R.J.M. Vullers, V. Leonov, T. Sterken, A. Schmitz, “Energy Scavengers For
Wireless Intelligent Microsystems,” Special Report in Microsystems &
Nanosystems, OnBoard Technology, June 2006
Imec, “Design for analog and RF technologies and systems,” www.imec.be
Imec, “Micropower generation and storage,” www.imec.be
F. Whetten, “Energy Harvesting Sensor Systems – A Proposed Application for
802.15.4f, ” DOC: IEEE802.15-09/0074-00-004f
C. Cossio, “Harvest energy using a piezoelectric buzzer,” EDN, pg.94-96,
March 20, 2008