1. DESIGN ANALYSIS AND OPTIMIZATION OF MEMS
PIEZOELECTRIC ENERGY HARVESTER
MENTOR: Ms Deeksha Chandola
Submitted by:
Vinamra Jha-9912102295
Sanskriti Shrivastva-9912102342
Ashish Singh-9912102371
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2. CONTENT :
 Objective
 MEMS
 Literature analysis
 Energy harvester
 Components
 Output power
 Simulation
 Future scope
 References
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3. OBJECTIVE:
 Designing of Energy Harvester using Piezoelectric material.
 Analysis of generated output power of the actuator designed.
 Optimization of the output power that depends on multiple
factors.
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4. MEMS:
 Micro-Electro-Mechanical Systems, or MEMS, is a technology which can be
defined as miniaturized electro-mechanical systems.
 The main criterion of MEMS is that there are at least some elements have some sort
of mechanical functionality.
 MEMS helps us in analyzing values below microns as well. COMSOL is the best
available simulator and it does not operate below nano scale as of now.
 Micro-electromechanical systems (MEMS) are very small devices or groups of
devices that can integrate both mechanical and electrical components.
 Here, the energy harvester is designed using MEMS technology, which stores energy
of the piezoelectric materials for its further use.
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5. LITERATURE ANALYSIS:
MATERIAL SELECTION:
From the prerequisite knowledge, we conclude that the Lead zicronate-titanate(PZT)
is the optimum choice for the energy harvester design proposed as:
 Performance under high stress i.e. High tensile strength
 Operability at high temperatures(greater than Curie temp)
 High permittivity
 Large coupling factor
 High piezoelectric charge coefficient
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6. ENERGY HARVESTER:
 According to the law of conservation of energy, energy can neither be created nor
destroyed. It can only be reused from one form to another. Energy harvester can be
considered as a medium for reusability of this energy.
 The energy harvester uses the principle of “piezoelectric effect” (piezo means press)
i.e. an electric charge is produced in return of the mechanical stress applied.
 Renewable Energy sources are the center of attraction for research and development
all over the world nowadays, the demand of a lasting cheap source of energy that is
environmental friendly, is the main challenge recently. Energy Harvesting is a new
technology that is going to make a revolution in the coming decade. Energy
Harvesting is a technique to provide alternative sources of energy that are
environmental friendly and low in cost.
Energy harvesting is also known as power harvesting or energy scavenging.
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7. COMPONENTS:
 Substrate: the word itself tell that it is the material or layer under lying something. It
is generally chosen to be as a solid material that can sustain all the motions taking
place above it.
 Anchor: The anchor provides us with a stable base that supports the cantilever beam.
 Cantilever beam: This beam is the main plank like setup over which the
piezoelectric layer is placed. This cantilever beam is kept mobile so that it can move
in a vertical harmonic motion and produces output power.
 Piezoelectric layer: Piezoelectric layer is placed right above the cantilever beam
because the piezoelectric layer is the one that will help in the generation of electric
charge due to apllication of stress.
 Proof mass: The proof mass can be considered as an important part of the complete
setup as this helps in motivating and enhancing the speed of vibrations that produce
the output power.
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8. Fig 1. 3-D model design of cantilever beam in COMSOL
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9. OUTPUT POWER:
 In physics, power is the rate of doing work. It is equivalent to an amount
of energy consumed per unit time.
 The integral of power over time defines the work performed.
 Power in mechanical systems is the combination of forces and
movement. Mechanical power is also described as the time derivative of
work.
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10. CALCULATIONS:
Where,
h=height of cantilever
l=length of cantilever beam
E=young’s modulus(169e9 Pa)
ρ=density(2320 Kg/m^3)
ρ = ............................................................................(eq 3)
.................................................................(eq 1)
....................................................................eq (2)
M=mass of proof mass
wB=displacement of cantilever beam
wN=angular frequency
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11. VOLUME= LENGTH X BREADTH X HIEGHT ...........................................eq(4)
= (125μm x 1 μm x 10 μm)
= 1250 μm
ρ = 2320 kg/ m-3
MASS= VOLUME X ρ
=2.9 x 106
wB=5.3 x 10-6
w = 2πf ......................................................................................................eq (5)
Thus,
wN=2πfN
=2 x 3.14 x 151.11
=9.48 x 10-3
Putting all these value in eqn (2), we get
P= 8.94 x 10-20 watts
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12. SIMULATION:
Fig 2- Simulation
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13. Parameters Reference paper Our results
Cantilever (3 x 2.4 x 0.005)mm3 (125 x 1 x 10) μm
Eigen frequency 234.75 Hertz 151.11 kHertz
Output power 66.75μW 8.94 x 10-20 Watts
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14. FUTURE SCOPE:
 As the time will elapse, the output power calculated will be optimized.
........................................................eq (6)
 Based on eqn (6), the frequency when reduced will increase the output
power.
 Based on eqn(1), when external parameters, like dimensions of the
cantilever beam, are changed the frequency will be decreased.
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15. REFERENCES:
[1] Comparison of Piezoelectric energy harvesting devices by Henry A. Sodano and
Daniel J. Inman
[2]Kasyap, A., Lim, J., Johnson, D., Horowitz, S., Nishida, T., Ngo, K., Sheplak, M.
and Cattafesta,L., 2002, “Energy Reclamation from a Vibrating Piezoceramic
Composite Beam,”
[3]Ramsey, M.J. and Clark, W.W., 2001, “Piezoelectric energy harvesting for bio
MEMS applications”
[4]Sodano, H.A., Inman, D.J. and Park, G., 2004a, “Generation and Storage of
Electricity from Power Harvesting Devices,”
[5] Sodano, Henry A., Daniel J. Inman, and Gyuhae Park. "Comparison of piezoelectric
energy harvesting devices for recharging batteries." Journal of Intelligent Material
Systems and Structures 16.10 (2005): 799-807.
[6] Liu, Jing-Quan, et al. "A MEMS-based piezoelectric power generator array for
vibration energy harvesting." Microelectronics Journal 39.5 (2008): 802-806.
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