This document summarizes research conducted on experimental analysis of a piezoelectric energy harvesting system under various vibration conditions. The research aims to show that accurate experimental testing is essential for harvester development by determining the implications of complex vibration characteristics on harvester performance. The research tests a commercially available piezoelectric transducer and conditioning circuit under harmonic, random, and sine on random vibration scenarios. The results show that theoretical power harvesting predictions require simplifying assumptions about input vibration and transducer characteristics that do not apply to real-world conditions. Testing more complex vibration profiles provides a more accurate representation of ambient vibrations and is valuable for harvester development.
Design and validation of piezoelectric energy harvesting systemsIlyas Caluwé
The aim of this study is to examine how small amounts of ambient energy, such as in vibrations or wind flow, can be converted to electrical energy and to build a working design.
The different energy harvesting principles found in literature are studied first. Piezoelectric energy harvesting was found suitable for both energy harvesting out of ambient vibrations and wind flow. A cantilevered beam setup with a piezopatch (MFC patch) is chosen because it has good power conversion characteristics, it is robust and versatile. Both vibration and wind flow harvesting devices can be constructed with this setup.
Vibration harvesting setups were constructed with both a commercially available bimorph piezoceramic harvester and with an unimorph harvester consisting of a stainless steel plate and a composite-reinforced piezoceramic patch attached to it. The power output is reported. The parameters that are of importance to optimize the setup are discussed.
The possibilities to use the beam for wind flow harvesting were explored. Different aeroelastic phenomena were studied to give insight into possible working principles. A number of designs are proposed and some are tested using the stainless steel plate with the MFC patch. The possibility of using aeroelastic stability to harvest energy is shown, and suggestions for further improvements are given.
Vibration Energy Harvesting - Between theory and realityKarim El-Rayes
This is the slides for a talk I have given at Sensors expo & conference 2017 in San Jose, CA, on vibrations energy harvesting. The talk discussed approaches in VEH, transduction mechanisms, common mechanical structures, design challenges and how to tackle them, in addition to a short survey on some VEHs and associated circuitry.
DESIGN & ANALYSIS OF RF ENERGY HARVESTING SYSTEM FOR CHARGING LOW POWER DEVICESJournal For Research
Finite electrical battery life is encouraging the companies and researchers to come up with new ideas and technologies to drive wireless mobile devices for an infinite or enhance period of time. Common resource constrained wireless devices when they run out of battery they should be recharged. For that purpose main supply & charger are needed to charge drained mobile phone batteries or any portable devices. Practically it is not possible to carry charger wherever we go and also to expect availability of power supply everywhere. To avoid such disadvantages some sort of solution should be given and that can be wireless charging of mobile phones.[4] If the mobile can receive RF power signals from the mobile towers, why can’t we extract the power from the received signals? This can be done by the method or technology called RF energy harvesting. RF energy harvesting holds a promise able future for generating a small amount of electrical power to drive partial circuits in wirelessly communicating electronics devices. RF power harvesting is one of the diverse fields where still research continues. The energy of RF waves used by devices can be harvested and used to operate in more effective and efficient way.
Design and validation of piezoelectric energy harvesting systemsIlyas Caluwé
The aim of this study is to examine how small amounts of ambient energy, such as in vibrations or wind flow, can be converted to electrical energy and to build a working design.
The different energy harvesting principles found in literature are studied first. Piezoelectric energy harvesting was found suitable for both energy harvesting out of ambient vibrations and wind flow. A cantilevered beam setup with a piezopatch (MFC patch) is chosen because it has good power conversion characteristics, it is robust and versatile. Both vibration and wind flow harvesting devices can be constructed with this setup.
Vibration harvesting setups were constructed with both a commercially available bimorph piezoceramic harvester and with an unimorph harvester consisting of a stainless steel plate and a composite-reinforced piezoceramic patch attached to it. The power output is reported. The parameters that are of importance to optimize the setup are discussed.
The possibilities to use the beam for wind flow harvesting were explored. Different aeroelastic phenomena were studied to give insight into possible working principles. A number of designs are proposed and some are tested using the stainless steel plate with the MFC patch. The possibility of using aeroelastic stability to harvest energy is shown, and suggestions for further improvements are given.
Vibration Energy Harvesting - Between theory and realityKarim El-Rayes
This is the slides for a talk I have given at Sensors expo & conference 2017 in San Jose, CA, on vibrations energy harvesting. The talk discussed approaches in VEH, transduction mechanisms, common mechanical structures, design challenges and how to tackle them, in addition to a short survey on some VEHs and associated circuitry.
DESIGN & ANALYSIS OF RF ENERGY HARVESTING SYSTEM FOR CHARGING LOW POWER DEVICESJournal For Research
Finite electrical battery life is encouraging the companies and researchers to come up with new ideas and technologies to drive wireless mobile devices for an infinite or enhance period of time. Common resource constrained wireless devices when they run out of battery they should be recharged. For that purpose main supply & charger are needed to charge drained mobile phone batteries or any portable devices. Practically it is not possible to carry charger wherever we go and also to expect availability of power supply everywhere. To avoid such disadvantages some sort of solution should be given and that can be wireless charging of mobile phones.[4] If the mobile can receive RF power signals from the mobile towers, why can’t we extract the power from the received signals? This can be done by the method or technology called RF energy harvesting. RF energy harvesting holds a promise able future for generating a small amount of electrical power to drive partial circuits in wirelessly communicating electronics devices. RF power harvesting is one of the diverse fields where still research continues. The energy of RF waves used by devices can be harvested and used to operate in more effective and efficient way.
In this presentation, it proposes efficient method of storing energy by the use of piezoceramic. It is very reliable to use
piezo ceramic for generating electrical energy which can be used for powering any portable devices. The basic concept
of piezo ceramic is that the mechanical strain applied on to the ceramic such as bimorph or unimorph piezo converts it
into electrical energy. In the present day scenerio, wherein there is great demand for energy, this idea of piezoelectric
concept works well.
RF Energy Harvesting for Wireless DevicesIJERD Editor
Radio Frequency (RF) energy transfer and harvesting techniques have recently become alternative methods to empower the next generation wireless networks. As this emerging technology enables proactive energy replenishment of wireless devices, it is advantageous in supporting applications with quality of service requirements. In this paper, some wireless power transfer methods, RF energy harvesting networks, various receiver architectures and existing applications are presented. Finally, some open research directions are envisioned.
What is islanding ?
Consider the power network as shown in fig.1
Now if we disconnect the line AB from the infinite transmission grid there will be an isolated region . The D1, D2 are power sources (eg : inverter , solar power cells ). The power generated in this region is fed to the island only.
We see that there no longer is any control over the island voltage at the bus X . Also there is no mechanism here for control of frequency.
This state is referred to as islanding.
Development of a Wireless Sensors Network powered by Energy Harvesting techni...Daniele Costarella
Develer Workshop:
A workshop focused on the principles and benefits of applying the Energy Harvesting techniques on Wireless Sensor Networks. The contents come from my Better Embedded 2013 talk.
Modeling and Simulation of Solar Photovoltaic module using Matlab/SimulinkIOSR Journals
Abstract: This paper presents the circuit model of photovoltaic (PV) module. Simulation and modeling is done
using MATLAB/ Simulink software package. The proposed model is user friendly and can be used as a common
platform for both applied physics scientist and power electronics engineers. A detailed modeling procedure is
presented. The designed model is verified by using STP255-20/Wd PV module. The IV and PV characteristics
are simulated at different temperature and irradiance conditions and the results are verified. The proposed
model is very simple fast and accurate. The designed model can be used for analysis of PV characteristics and
for simulation of maximum power point tracking algorithms
A single stage photo voltaic grid-connected inverter using spwmSHAIK AMANULLA
A Single-stage PhotoVoltaic Grid-Connected Inverter using SPWM. It was simulated and modeled with MATLAB/SIMULINK. It was simulated with constant and variable irradiation profiles. I got the results with variations in PV characteristics with different irradiation with SPWM technique.
This slides are the Ph.D. work presentation on Active Power Filter design and implementation for harmonic elimination in micro-grid and electric vehicle
Power Estimation for Wearable Piezoelectric Energy HarvesterTELKOMNIKA JOURNAL
The aim of this research work is to estimate the amount of electricity produced to power up wearable devices using a piezoelectric actuator, as an alternative to external power supply. A prototype of the device has been designed to continuously rotate a piezoelectric actuator mounted on a cantilever beam. A MATLAB® simulation was done to predict the amount of power harvested from human kinetic energy. Further simulation was conducted using COMSOL Multiphysics® to model a cantilever beam with piezoelectric layer. With the base excitation and the presence of tip mass at the beam, the natural frequencies and mode shapes have been analyzed to improve the amount of energy harvested. In this work, it was estimated that a maximum amount of power that could be generated is 250 μW with up to 5.5V DC output. The outcome from this research works will aid in optimising the design of the energy harvester. This research work provides optimistic possibility in harvesting sufficient energy required for wearable devices.
These slides present the maximum power point tracking (MPPT ) algorithms for solar (PV) systems. Later of the class we will discuss on MPPT control of wind generators.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Types of islands in power systems with DR
Issues with unintentional islands
Methods of protecting against unintentional islands
Standard testing for unintentional islanding
Advanced testing of inverters for anti-islanding functionality
Probability of unintentional islanding
The future of anti-islanding protection
What is energy harvesting?
What are some of its applications?
Can we make that at home?
#WikiCourses
https://wikicourses.wikispaces.com/XTopic+Energy+Harvesting
In this presentation, it proposes efficient method of storing energy by the use of piezoceramic. It is very reliable to use
piezo ceramic for generating electrical energy which can be used for powering any portable devices. The basic concept
of piezo ceramic is that the mechanical strain applied on to the ceramic such as bimorph or unimorph piezo converts it
into electrical energy. In the present day scenerio, wherein there is great demand for energy, this idea of piezoelectric
concept works well.
RF Energy Harvesting for Wireless DevicesIJERD Editor
Radio Frequency (RF) energy transfer and harvesting techniques have recently become alternative methods to empower the next generation wireless networks. As this emerging technology enables proactive energy replenishment of wireless devices, it is advantageous in supporting applications with quality of service requirements. In this paper, some wireless power transfer methods, RF energy harvesting networks, various receiver architectures and existing applications are presented. Finally, some open research directions are envisioned.
What is islanding ?
Consider the power network as shown in fig.1
Now if we disconnect the line AB from the infinite transmission grid there will be an isolated region . The D1, D2 are power sources (eg : inverter , solar power cells ). The power generated in this region is fed to the island only.
We see that there no longer is any control over the island voltage at the bus X . Also there is no mechanism here for control of frequency.
This state is referred to as islanding.
Development of a Wireless Sensors Network powered by Energy Harvesting techni...Daniele Costarella
Develer Workshop:
A workshop focused on the principles and benefits of applying the Energy Harvesting techniques on Wireless Sensor Networks. The contents come from my Better Embedded 2013 talk.
Modeling and Simulation of Solar Photovoltaic module using Matlab/SimulinkIOSR Journals
Abstract: This paper presents the circuit model of photovoltaic (PV) module. Simulation and modeling is done
using MATLAB/ Simulink software package. The proposed model is user friendly and can be used as a common
platform for both applied physics scientist and power electronics engineers. A detailed modeling procedure is
presented. The designed model is verified by using STP255-20/Wd PV module. The IV and PV characteristics
are simulated at different temperature and irradiance conditions and the results are verified. The proposed
model is very simple fast and accurate. The designed model can be used for analysis of PV characteristics and
for simulation of maximum power point tracking algorithms
A single stage photo voltaic grid-connected inverter using spwmSHAIK AMANULLA
A Single-stage PhotoVoltaic Grid-Connected Inverter using SPWM. It was simulated and modeled with MATLAB/SIMULINK. It was simulated with constant and variable irradiation profiles. I got the results with variations in PV characteristics with different irradiation with SPWM technique.
This slides are the Ph.D. work presentation on Active Power Filter design and implementation for harmonic elimination in micro-grid and electric vehicle
Power Estimation for Wearable Piezoelectric Energy HarvesterTELKOMNIKA JOURNAL
The aim of this research work is to estimate the amount of electricity produced to power up wearable devices using a piezoelectric actuator, as an alternative to external power supply. A prototype of the device has been designed to continuously rotate a piezoelectric actuator mounted on a cantilever beam. A MATLAB® simulation was done to predict the amount of power harvested from human kinetic energy. Further simulation was conducted using COMSOL Multiphysics® to model a cantilever beam with piezoelectric layer. With the base excitation and the presence of tip mass at the beam, the natural frequencies and mode shapes have been analyzed to improve the amount of energy harvested. In this work, it was estimated that a maximum amount of power that could be generated is 250 μW with up to 5.5V DC output. The outcome from this research works will aid in optimising the design of the energy harvester. This research work provides optimistic possibility in harvesting sufficient energy required for wearable devices.
These slides present the maximum power point tracking (MPPT ) algorithms for solar (PV) systems. Later of the class we will discuss on MPPT control of wind generators.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Types of islands in power systems with DR
Issues with unintentional islands
Methods of protecting against unintentional islands
Standard testing for unintentional islanding
Advanced testing of inverters for anti-islanding functionality
Probability of unintentional islanding
The future of anti-islanding protection
What is energy harvesting?
What are some of its applications?
Can we make that at home?
#WikiCourses
https://wikicourses.wikispaces.com/XTopic+Energy+Harvesting
These slides use concepts from my (Jeff Funk) course entitled analyzing hi-tech opportunities to show how energy harvesters are becoming more economically feasible for the Internet of Things (IoT). Small amounts of energy can be harvested from vibrations, temperature differences, and radio frequencies using various types of electronic devices such as piezoelectric, MEMS, thermo-electric power generators, and other devices. As improvements in them occur and as the energy requirements of accelerometers, pressure sensors, gas detectors, bio-sensors, and readout circuits fall from microwatts to hundreds of nano-watts, energy harvesters become cheaper and better than are batteries. Improvements in energy harvesting are occurring in the form of higher power per area or higher power per temperature difference and improvements of about five times are expected to occur in the next 5 to 10 years. The market for energy harvesters is expected to reach $2.5 Billion by 2024. In addition to their impact on buildings and the other usual applications for IoT, they will also impact on agriculture, aircraft, and medical implants.
In an age where every teeny tiny bit of electricity is valued, conservation is much talked about, can piezoelectricity be the messiah to ease the burden off the conventional energy sources?
Who says it cannot?
--
Presentation as a part of seminar coursework.
youtube project created for CRS 225 Public Advocacy, Syracuse University
Song featured: The Cave - Mumford & Sons
I do not claim to hold any rights to the song used and credit Mumford & Sons
Sound or popularly known to us as noise is one of the widely available energy sources which have its range extending al-most to infinity. The noise is considered to be a great contribu-tor in the increasing pollution which is studied under the cat-egory of noise pollution.
Let us first understand the basic definition of sound. Sound basically is mechanical wave that is an oscillation of pressure transmitted through some medium (like air or water), com-posed of frequencies which are within the range of hearing. Thus, considering sound as the wave we can imagine it as the flow of energy from one point to another with the help of a medium as air. The sound waves can be longitudinal as well as transverse as per direction of vibration of the sound parti-cles called phonons.
Sound that is perceptible by humans has frequencies from about 20 Hz to 20,000 Hz. In air at standard temperature and pressure, the corresponding wavelengths of sound waves range from 17 m to 17 mm.
Electricity from vibration & its impactSagardwip das
With the growing demands of human needs the utilisation of conventional energy has increased tremendously. Consequently environmental issues like global warming etc. have risen. Keeping these facts in view this model has been prepared to present an idea on how the daily energy requirement can be fulfilled in a more practical, feasible and economical way by converting mechanical energy of vibration into electric energy
The power generation using solar photovoltaic (PV) system in microgrid requires energy storage system due to their dilute and intermittent nature. The system requires efficient control techniques to ensure the reliable operation of the microgrid. This work presents dynamic power management using a decentralized approach. The control techniques in microgrid including droop controllers in cascade with proportional-integral (PI) controllers for voltage stability and power balance have few limitations. PI controllers alone will not ensure microgrid’s stability. Their parameters cannot be optimized for varying demand and have a slow transient response which increases the settling time. The droop controllers have lower efficiency. The load power variation and steady-state voltage error make the droop control ineffective. This paper presents a control scheme for dynamic power management by incorporating the combined PI and hysteresis controller (CPIHC) technique. The system becomes robust, performs well under varying demand conditions, and shows a faster dynamic response. The proposed DC microgrid has solar PV as an energy source, a lead-acid battery as the energy storage system, constant and dynamic loads. The simulation results show the proposed CPIHC technique efficiently manages the dynamic power, regulates DC link voltage and battery’s state of charge (SoC) compared to conventional combined PI and droop controller (CPIDC).
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Distributed energy resources (DER) based micro grid and Nano-grid framework is most technically viable bottom-top approach to sustainably meet ever-increasing demand of rural and urban communities. Recently the growth of DC operative home appliances like mobile and lap top chargers, ovens and hair dryer’s etc. are increasing and therefore a DC/DC converter is an efficient way to meet the electricity need from the local DER and helps in improving the system efficiency. This paper presents simulation results of a buck boost converter, MPPT algorithm (P & O method) for solar PV module and closed loop PI control system for obtaining constant 12 V and 24 V DC output voltage at DC bus. The proposed methodology is to extract maximum DC power from solar PV system and it is directly fed to DC load or DC Nano grid.
Now-a-days, power generation and utilization became more complicated which further affects the economy of a country. The available non-renewable energy sources that supply the demanded power do not consider environmental challenges like global warming and pollution. This leads to the development of power generation based on Renewable Energy Resources (RES). These RES are connected to the grid through power electronic converters which offer countless power quality issues that must be rectified to deliver a quality power to the end users. The proposed work uses a three phase Voltage Source Inverter (VSI) based Shunt Active Power Filter (SAPF) fed by solar Photo Voltaic (PV) system to eliminate current harmonics at the source side of the grid. The output of the PV system is given to a boost converter along with self–lift single-ended primary-inductor converter (SEPIC) for supplying high voltage gain which is accompanied by a Perturb & Observe Maximum Power Point Tracking (MPPT).The main objective of this paper is to eliminate the current harmonics at the grid side using SAPF. Also, the proposed SAPF is used for exporting the power generated from PV to the grid. The overall system performance is validated with a help of MATLAB/SIMULINK.
Dynamic Power Reduction of Digital Circuits by ClockGatingIJERA Editor
In this paper we have presented clock gating process for low power VLSI (very large scale integration) circuit design. Clock gating is one of the most quite often used systems in RTL to shrink dynamic power consumption without affecting the performance of the design. One process involves inserting gating requisites in the RTL, which the synthesis tool translates to clock gating cells in the clock-path of a register bank. This helps to diminish the switching activity on the clock network, thereby decreasing dynamic power consumption within the design. Due to the fact the translation accomplished via the synthesis tool is solely combinational; it is referred to as combinational clock gating. This transformation does not alter the behavior of the register being gated.
The microgrid concept introduces the reduction of multiple conversions in an individual AC or DC grid and also facilitates connections to variable renewable AC and DC sources and loads to power system.
PERFORMANCE OF MVDC AND MVAC OFFSHORE WIND FARM DISTRIBUTION SYSTEMJournal For Research
Offshore wind farms are becoming more popular because of advantages such as availability of higher and uniform wind speeds, availability of the large sea area and proximity to major load centers. Two types of wind turbine systems for wind power generation exist. Mainly DFIG (30% speed variation) and PMSG (100 % speed variation) generators are used in wind farms. To evaluate any power system network, load flow analysis is necessary. But traditional load flow methods such as the GS and NR-techniques fail to meet the requirements in both performance and robustness aspects of radial connected wind farm distribution systems. Therefore in this work, the direct approach algorithm is used for wind farms in which generators are modelled as PQ bus and transmission line modelled using À model in the algorithm. Basically two types of configuration are possible Medium Voltage AC (MVAC) and Medium Voltage DC (MVDC) offshore WFDS. Due to lower losses in MVDC offshore WFDS, a today lot of research is going on to design MVDC offshore WFDS. The results are presented for both MVAC and MVDC based offshore wind farm distribution system using MATLAB programming. Finally, a performance comparison has been made between the MVAC and MVDC based offshore Wind Farm Distribution System (WFDS).
Similar to Vibration Energy Harvesting: Going Beyond Idealization (20)
PERFORMANCE OF MVDC AND MVAC OFFSHORE WIND FARM DISTRIBUTION SYSTEM
Vibration Energy Harvesting: Going Beyond Idealization
1. Experimental analysis of a piezoelectric
energy harvesting system for
harmonic, random, and sine on random
vibration
JACKSON W. CRYNS
B.S. Applied Mathematics, Engineering and Physics
University of Wisconsin - Madison
Research conducted under Brian K. Hatchell (PNNL) in fulfillment of DOE Office of Science, Science
Undergraduate Laboratory Internship (SULI) and to support projects contracted by the U.S. Army
Sigma Xi - Student Research Showcase 2013
March, 2013 Sigma Xi - Student Resarch Showcase 1
2. Abstract
Advancements in low power electronics in the past decade allow systems to run off of
progressively less energy and even eliminate the need for external power supplies
completely. The key to self-sustaining electronics is the ability to harness energy from
the surrounding environment and turn it into usable electrical energy, or Energy
Harvesting. In many industrial applications, ambient energy is readily available in the
form of mechanical vibrations. Piezoelectric ceramics provide a compact, energy dense
means of transducing mechanical vibrations of the environment to electrical power.
Harvesting power with a commercially available piezoelectric vibration powered
generator using a full-wave rectifier conditioning circuit is experimentally compared for
varying sinusoidal, random and sine on random (SOR) input vibration scenarios. Much
of the available literature focuses on maximizing harvested power through theoretical
predictions and power processing circuits that require accurate knowledge of generator
internal electromechanical characteristics and idealization of input vibration, which
cannot be assumed in general application. Characteristics of complex vibration sources
significantly alter power generation and processing requirements, likely rendering
idealized analysis inaccurate. Going beyond idealized steady state sinusoidal and
simplified random vibration input, SOR testing allows for more accurate representation
of real world ambient vibration and is an invaluable tool in harvester development.
March, 2013 Sigma Xi - Student Resarch Showcase 2
3. Background
What is Energy Harvesting?
Application Goals
Vibration Powered Generators (Transducers)
Piezoelectric Effect
Power Conditioning
March, 2013 Sigma Xi - Student Resarch Showcase 3
4. What is Energy Harvesting?
• Every process dissipates waste energy to the surrounding environment
• Ambient energy comes in many usable forms
[5]
Electromagnetic Radiation (1) Thermal Gradient (2) Potential Energy Forms (3) Vibration (Potential + Kinetic) (4)
• Convert ambient energy to usable electrical energy – transducers
• Small amounts of power – mW or µW (milli-Watts or micro-Watts) [3]
(5) (6) (7) (8)
• Not a new idea!
March, 2013 Sigma Xi - Student Resarch Showcase 4
5. Application Goals
Supply power to off grid devices
Remote equipment
Monitors in hazardous environments (9)
Wireless data logging and transmission
Reduce maintenance requirements and costs
Relieve dependence on primary batteries
(10)
Fits into national “green” initiatives
March, 2013 Sigma Xi - Student Resarch Showcase 5
6. Vibration Powered Generators (Transducers)
Machines, moving parts and large power generators present
significant vibration energy [2, 3, 8]
Three transduction mechanisms [1, 8, 10]:
Electrostatic – parallel plate capacitor
Electromagnetic – magnetic induction
Piezoelectric – piezoelectric effect
Numerous studies have been conducted on power transduction [15,3,9]
(11) (12) (13)
Driving and Biking Walking Numerical and Theoretical Simulations
Piezoelectric transducers are the most energy dense [8,12]
March, 2013 Sigma Xi - Student Resarch Showcase 6
7. Piezoelectric Effect
Electric charge accumulates in certain materials in response to
applied mechanical stress [11]
(14) (15)
This study analyzes a commercially available bimorph transducer
Two piezoelectric layers
Two electrical signals of opposite sines
March, 2013 Sigma Xi - Student Resarch Showcase 7
8. Power Conditioning
Conditioning circuitry – the components necessary to supply power
from the transducer to the target electronics with specified current and
voltage characteristics
(16)
Example conditioning circuit
This study includes the target electronics in the conditioning circuit
March, 2013 Sigma Xi - Student Resarch Showcase 8
9. Research Overview
Research Goals {10}
Energy Harvesting Architecture {11 – 18 }
Literature Review and Harvester Validation {19 – 36}
Expanded Vibration Testing {37 – 46}
Discussion and Design Implications {47 – 50}
March, 2013 Sigma Xi - Student Resarch Showcase 9
10. Research Goals
Convince the reader that accurate experimental testing is an
invaluable and essential tool in harvester development
Determine implications of complex vibration characteristics on
harvester performance
Show that theoretical power harvesting predictions and numerical
simulations require assumptions that cannot be made in general
application:
Oversimplifying assumptions of input vibration
Exact knowledge of transducer internal electrical and mechanical
characteristics
March, 2013 Sigma Xi - Student Resarch Showcase 10
12. Energy Harvesting Architecture
Piezoelectric transducer
V25w QuickPack® actuator
produced by Midé [24,25]
AC signal
Proof mass
(for frequency tuning)
Rigid clamp
(fixed-free cantilever beam)
Vibration Source Exact transducer internal electrical and
mechanical characteristics unknown
LDS V721 – 1000 L shaker
Closed loop vibration control
[17]
Power conditioning circuitry
Standard circuit
March, 2013 12
13. Energy Harvesting Architecture
Piezoelectric Transducer Set-Up
Mount in cantilever configuration
Input vibration at base
Natural frequency
[18]
Tune with proof mass to match source vibration
Modal analysis allows for accurate natural frequency determination
Bare natural frequency of 124.5 Hz
March, 2013 Sigma Xi - Student Resarch Showcase 13
14. Energy Harvesting Architecture
Power Conditioning Duties
AC-DC conversion [19]
Transducer creates AC signal (oscillatory)
Most microelectronics require DC
Full-wave bridge rectifier
Signal smoothing
A time varying signal is damaging
to DC electronics
[20]
Provide power to load
Microelectronics
Resistor
Secondary (rechargeable) battery
http://www.electronics-tutorials.ws/diode/diode_6.html
http://www.eleinmec.com/article.asp?18
March, 2013 Sigma Xi - Student Resarch Showcase 14
15. Energy Harvesting Architecture
Power Conditioning Circuitry [3,7,14-16,26]
Standard (linear) Interface
Target electronics (load) modeled represented by resistor
Net transfer of energy through transient components is null, thus equivalent
resistance is sufficient
Capacitance is constant, locate optimal impedance by varying resistance
CR = 600 µF, RL -> variable.
Non-linear processing not considered in this study
Designed for steady sinusoidal vibration only
Dissipates extra power
Application specific designs require additional voltage control
Additional control circuitry always dissipates extra power
Circuit used here finds the maximum available power for harvesting
(except for loses in rectifier bridge and capacitor leakage)
March, 2013 Sigma Xi - Student Resarch Showcase 15
16. Energy Harvesting Architecture
Test multiple scenarios Impedance head
Harmonic, Random – simplified
SOR – sine and random
superposition for accurate testing
Characterize and control the input
vibration by acceleration
Acceleration response is the most Shaker armature
common form of vibration
measurement and characterization
Allows for subsequent validation in
other experiments
Method assumes harvester does
not alter input dynamics (source is
much larger than harvester) [31]
Monitor force and acceleration with
PCB impedance head 288D01
March, 2013 Sigma Xi - Student Resarch Showcase 16
18. Energy Harvesting Architecture
Fundamental Objective:
How does power harvesting vary with input acceleration
characteristics, transducer natural frequency, and load resistance?
Measure voltage and current delivered to load to find harvested power
Measure input acceleration and force to find input power, when needed
March, 2013 Sigma Xi - Student Resarch Showcase 18
19. Literature Review and
Harvester Validation
General
Sinusoidal input vibration*
Flat random vibration*
*Analytical relations for purely sinusoidal and flat broadband vibration have been developed in other
works for custom developed harvesters and simulations [6, 9 ,18-20]
March, 2013 Sigma Xi - Student Resarch Showcase 19
20. Literature Review and Harvester Validation
Properly developed harvesters can harvest tens to hundreds of mW of
power [1, 3, 6-9]
Vibration Energy Harvesters (VEH) require careful development for
effective power conversion
Characterization of ambient source vibration
Tuning of transducer to achieve resonance
Determination of optimal impedance
Harvesting electrical power induces mechanical damping and alters
the transducer vibration dynamics, creating an electromechanical
system [9]
March, 2013 Sigma Xi - Student Resarch Showcase 20
21. Literature Review and Harvester Validation
Conditioning circuitry designs can range from a few analog
components to complex architectures controlled by firmware [3,7,14-
16,26]
Non-linear power processing has been shown to significantly increase
harvested power over passive (standard) power processing
Synchronized Charge Extraction (SEC)
Synchronized Switch Harvesting with Inductor (SSHI)
Additional control circuitry dissipates extra power, reducing efficiency
[21]
March, 2013 Sigma Xi - Student Resarch Showcase 21
22. Literature Review and Harvester Validation
Previous research heavily focused on two idealized vibration cases:
steady state sinusoidal vibration sources and flat, broadband
random profiles [1, 6, 7, 9, 12, 13, 16, 17]
Analysis and modeling are simplified in these cases
Non-linear SSHI requires steady state sinusoidal
Non-linear SEC performance drops in non-sinusoidal vibration
environments
Many studies omit inclusion of the significant power loss from additional
control circuitry that can be on the order of hundred of μW []
No studies addressed voltage fluctuations induced by random vibration
[22] [23]
March, 2013 Sigma Xi - Student Resarch Showcase 22
23. Literature Review and Harvester Validation
Few studies incorporated more complex vibrational sources [2,18]
Sinusoidal and flat random vibration inputs are scarce in application
Real ambient conditions can be accurately modeled by incorporating both
random and sinusoidal content
Acceleration Spectral Density of a
typical Apache Helicopter flight is
significantly more complex than
sinusoidal or flat random vibration
• Peaks are accounted for by
sinusoidal components superposed
on top of a random profile
March, 2013 Sigma Xi - Student Resarch Showcase 23
24. Literature Review and Harvester Validation
Experimental Sinusoidal Input Validation
Unless otherwise stated, harvester is driven at the transducer natural
frequency
Sinusoidal vibrations are characterized by driving frequency and
amplitude
“Amplitude” refers to acceleration amplitude, zero to peak
March, 2013 Sigma Xi - Student Resarch Showcase 24
25. Literature Review and Harvester Validation
Sinusoidal – Amplitude variation
Theoretical Expectations:
Displacement and voltage scale linearly with input amplitude
Power scales quadratically with voltage and thus amplitude
Quadratic trend is clearly exhibited
at two natural frequencies.
March, 2013 Sigma Xi - Student Resarch Showcase 25
26. Literature Review and Harvester Validation
For identical input amplitudes:
lower natural frequencies harvest
more power. *
* Consequence of input power variations
March, 2013 Sigma Xi - Student Resarch Showcase 26
27. Literature Review and Harvester Validation
Sinusoidal – Impedance Variation
Theoretical Expectations:
Resistance (impedance) effects harvested power
Optimal resistance varies with natural frequency
Optimal resistance is around 40 kΩ and 15 kΩ for 58.3Hz and 124.5 Hz respectively
March, 2013 Sigma Xi - Student Resarch Showcase 27
28. Literature Review and Harvester Validation
Sinusoidal – Impedance Variation (cont’d)
As natural frequency
increases, optimal impedance
decreases and peak narrows
March, 2013 Sigma Xi - Student Resarch Showcase 28
29. Literature Review and Harvester Validation
Sinusoidal –Frequency Response Function (FRF) for power
Theoretical expectations:
All mechanical vibratory systems have a frequency dependent transfer
function
Deviating from natural frequency lowers the resulting transducer dynamic
amplitudes and thus harvested power
Harvested power drops by
approximately 50% within 1 Hz deviation
from natural frequency, reinforcing the
importance of accurate tuning of
transducer
Implies that there is an approximate
non-negligible transducer bandwidth of
+/- 3 Hz in which power is generated
March, 2013 Sigma Xi - Student Resarch Showcase 29
30. Literature Review and Harvester Validation
Experimental Random Input Validation
The terms broadband and random vibration are often used
interchangeably, but random vibrations need not be broad in general
Power is averaged of 100s samples to increase repeatability
Random vibrations vary statistically in time [18]
Random vibrations are characterized by Power Spectral Density
(PSD), or acceleration spectral density, profile in units of [g2/Hz]
Integrating the PSD over a frequency range and taking the square root
results in the Root Mean Square (RMS) level of vibration in g’s for that
filtered frequency range
“Amplitude” refers to spectral density near the transducer natural
frequency
It is shown later that spectral densities far from the resonant frequency
negligibly influence the harvester
March, 2013 Sigma Xi - Student Resarch Showcase 30
31. Literature Review and Harvester Validation
Random – Amplitude Variation
Theoretical Expectations:
Power scales linearly with spectral density
Power scales inversely with natural frequency, as with sinusoidal
As derived in [18], harvested power
varies linearly with spectral density
March, 2013 Sigma Xi - Student Resarch Showcase 31
32. Literature Review and Harvester Validation
Random – Impedance Variation
Theoretical Expectations:
Random vibration has higher optimal resistance than sinusoidal vibration
Optimal impedance scales inversely with natural frequency
Optimal resistance is higher for
random vibration than
sinusoidal vibration for both
frequencies, and decreases
with natural frequency for
each vibration type
March, 2013 Sigma Xi - Student Resarch Showcase 32
33. Literature Review and Harvester Validation
Random – Bandwidth Variation
Theoretical Expectations:
Power is independent of input bandwidth when significantly longer than
that of transducer
Unspecified results for short bandwidths or varying spectral density profile
shapes
Except for random statistical
deviations from one point the
next, average harvested power
is constant over all bandwidths
March, 2013 Sigma Xi - Student Resarch Showcase 33
34. Literature Review and Harvester Validation
Random – Frequency Variation
Theoretical Expectations:
Harvested power is inversely proportional to transducer natural frequency
For identical input amplitudes and
bandwidths, higher natural frequencies produced
less power
March, 2013 Sigma Xi - Student Resarch Showcase 34
35. Literature Review and Harvester Validation
Harvester met and agreed with theoretical predictions for special cases
Steady state sinusoidal vibration
Flat broadband vibration
Limitations of idealized studies
Real sources commonly consist of numerous sinusoidal peaks, complex
random profiles, nonlinear and transient interactions
No found studies incorporated non-flat random profiles
No found studies incorporated multiple sinusoidal components
No found studies incorporated interactions of both sinusoidal and random
content
No found studies addressed time variations in random vibrations
March, 2013 Sigma Xi - Student Resarch Showcase 35
36. Expanded Vibration Testing
Short bandwidth and non-flat random profiles
Sinusoidal and random component interaction
Multiple sinusoidal component interaction
March, 2013 Sigma Xi - Student Resarch Showcase 36
37. Expanded Vibration Testing
Random – Short Bandwidth Variation
Test varying bandwidths with identical gRMS values
Each random profile in the left plot has a 0.1414 gRMS acceleration level
(note that 50 Hz and 500 Hz expand beyond plot window)
Each scenario was supplied to the bare transducer to produce right plot
The harvester gets progressively worse at harvesting power as bandwidth increases, for
identical input power and gRMS levels.
38. Expanded Vibration Testing
Random – Non-Flat profile
Test impact of spectral density profile variations
Varying shape outside the transducer natural frequency
Identical in the bandwidth of the transducer (124.5 Hz 3 Hz)
Three profiles produced nearly identical
output powers of 0.65, 0.67, and 0.71
μW respectively.
Implies harvested power depends only
on the spectral density near the natural
frequency, other densities do not affect
harvested power.
March, 2013 Sigma Xi - Student Resarch Showcase 38
39. Expanded Vibration Testing
SOR – Constant Sinusoid, Variable Spectral Density
Test the effects of noise when harvesting from sinusoidal peak
0.3 g sinusoidal peak and increasing spectral density, PSDs plotted on left
Linear superposition suggests that power should increase, above the
sinusoidal power, as seen in random vibration
Harvested power increases with spectral density, however differently from the random
case due to time domain variations and imperfect super position in control software
March, 2013 39
40. Expanded Vibration Testing
SOR – Optimal Resistance
Determine the optimal resistance when both sinusoidal and random
content is present
Sinusoidal and random cases had significantly different optimal resistances
Does SOR bridge this gap?
Optimal resistance increases from
~15kΩ for sinusoidal to ~45kΩ for
random as spectral density
increases.
In other words, as vibration
dominance shifts from sinusoidal to
random, so does the optimal
resistance
March, 2013 Sigma Xi - Student Resarch Showcase 40
41. Expanded Vibration Testing
SOR – Multiple Sinusoidal Components
Test interactions of two dominant sinusoidal components
Two tones seen within 3 Hz of each other in Apache helicopter vibration
More components increase input power in the transducer bandwidth
FRF shows that harvested power value depends of frequency separation
Test two tones of 0.3 g amplitude at 58.3 Hz natural frequency
As frequency separation
increases, harvested power approaches
that of a single sinusoid at the natural
frequency.
At 0.25 Hz separation, average harvested
power is 28% higher
More than 1 Hz separation, harvested
power is only a few % higher
March, 2013 41
42. Expanded Vibration Testing
SOR – Multiple Sinusoidal Components (cont’d)
Multiple sine components induce significant amplitude beating in
source vibration and output voltage
With negligible random vibration levels, input vibration reaches zero (left)
Filter capacitor prevents load voltage from dropping to zero and alters the
input voltage from the transducer (right)
March, 2013 Sigma Xi - Student Resarch Showcase 42
43. Expanded Vibration Testing
SOR – Multiple Sinusoidal Components (cont’d)
Amplitude beating is dependent on frequency separation
FRF suggests beating should decrease with separation
As frequency separation
increases, beat amplitude approaches
zero
For two sinusoidal components 0.25 Hz
apart, load voltage beats at nearly
100% of single sine component voltage
(~8 V at 58.3 Hz and 3.5 V at 124.5 Hz)
March, 2013 43
44. Expanded Vibration Testing
SOR – Multiple Sinusoidal Components (cont’d)
Inclusion of more sine components in the transducer bandwidth
amplifies effects
Average harvested power and amplitude beating both increase
As number of sinusoidal components increases, responses approaches
that of random vibration with high spectral density
Test three 0.3 g sine components supplied to the bare transducer
March, 2013 44
45. Expanded Vibration Testing
Voltage Fluctuations
Interactions between frequencies induce fluctuations in voltage
delivered to the load
DC electronics are typically, designed to utilize a constant voltage supply
Even slight voltage fluctuations cause electronic devices to drop out of
regulation, affect sensor readings and damage the components
No found studies discussed implications of voltage fluctuations
Sinusoidal vibrations provide nearly constant voltage to the load
See the left plot on slide 18 (the capacitor voltage is the voltage supplied to the load)
Random vibrations induce significant voltage supply fluctuations
SOR vibrations can result in quite complicated vibration interactions
and voltage supply waveforms
March, 2013 Sigma Xi - Student Resarch Showcase 45
46. Expanded Vibration Testing
Voltage Fluctuations (cont’d)
Load supply voltage fluctuations scale with amplitude
Multiple sinusoidal components and random vibrations alter waveform
Sample time responses for 500 Hz bandwidth
random signals supplied to a transducer tuned
to 58.3 Hz at varying spectral densities
Peak to peak:
0.36 V at 2.5e-4 g2/Hz and
3.61 V at 5e-3 g2/Hz
Input power within the transducer natural frequency scales average power
(i.e. including a single sinusoidal component, as in slide 39, translates
waveform vertically but does not increase fluctuation intensity)
March, 2013 46
48. Discussion and Design Implications
Steady state, sinusoidal vibration is the most ideal form of input
vibration
Only requires design for natural frequency and optimal impedance
Lower frequencies harvest more power for similar amplitudes
No significant voltage fluctuations
No time dependencies
Rarely seen application
Random vibration is the least ideal form of input vibration
Only requires design for natural frequency and optimal impedance
Significantly less efficient than sinusoidal
In order to harvest significant power spectral densities, more than 1e-3 g2/Hz
are typically needed
Usually only 1e-6 to 1e-4 g2/Hz in application [2,8,32]
Overshadowed by voltage fluctuations, requires additional charge control
circuitry
March, 2013 Sigma Xi - Student Resarch Showcase 48
49. Discussion and Design Implications
Designing a harvester for use with complex vibration sources requires
acknowledgement of more characteristic factors than sinusoidal or
random vibration
Sinusoidal frequencies, number of sinusoidal components, separation
between sinusoidal components, random spectral density
profile, determination of optimal impedance
Ignoring random content or nearby sinusoidal content gives a poor
representation of harvested power and load voltage
Ignoring random content gives incorrect optimal impedance
Harvested power gains from additional random component or multiple
sinusoidal components are overshadowed by induced voltage fluctuations
Improper source vibration and harvester response representation
during development hurts application
Lowers power harvesting ability and efficiency
Omitting necessary voltage control and processing circuitry can bring
about unexpected consequences such as inaccurate sensor
readings, poor circuit functionality and possible damage to target
electronics
March, 2013 Sigma Xi - Student Resarch Showcase 49
50. Conclusion
Idealized sinusoidal and random vibration studies are NOT sufficient
for general harvester development
Environments with sufficiently low noise or random vibration levels and
sufficiently spread dominant frequencies may suffice
Theoretical and numerical predictions hinge upon exact knowledge of
transducer mechanical and electrical properties
This cannot be assumed in general
Internal transducer electrical and mechanical properties are unknown
unless custom developed by applicant
Sine on random vibration testing and experimental validation is an
essential tool in harvester development
SOR testing can recreate almost any vibration environment
SOR control can provide accurate quantitative results when harvesting
from complex vibrational sources
March, 2013 Sigma Xi - Student Resarch Showcase 50
51. Acknowledgements
Brian Hatchell for mentoring me through this experimental process
and providing the inspiration for the project
Emiliano Santiago-Rojas for applying electrical expertise and making
this cross discipline application possible
Karen Wieda for advising and aiding my assimilating into the PNNL
research environment
A special thanks to:
Department of Energy – Office of Science and the U.S. Army for making
this research project possible
51
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