Piezoelectric electric based energy harvesting

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Piezoelectric electric based energy harvesting

  1. 1. Piezoelectric Electric based energy harvesting Nuthan Raju V. Karthik T.P Mohd Jaffar Ahmed Khan M.S.Ramaiah School of Advanced Studies 1
  2. 2. Contents• Introduction• Simple molecular model• Energy Harvesting• Piezoelectric Energy Harvesting• Sources of vibration for crystal• Applications of piezoelectricity• Conclusion M.S.Ramaiah School of Advanced Studies 2
  3. 3. Introduction Piezoelectricity, discovered by Curie brothers in 1880, originated from the Greek word“piezenin”, meaning, to press. The original meaning of the word “piezoelectric” implies “Pressure electricity’ –the generation ofelectric field from applied pressure. This definition ignores the fact that the process is reversible,thusallowing the generation of mechanical motion by applying a field. Piezoelectricity is observed if astress is applied to a solid, for example, by bending twisting or squeezing it. The piezoelectric effect is a special material property that exists in many single crystalline materials.Some such crystalline structures are Quartz, Rochelle salt, Topaz, Tourmaline, Cane sugar, Berlinite(AlPO4), bone, tendon, silk, enamel, dentin, Barium Titanate (BaTiO3), Lead Titanate (PbTiO3),Potassium Niobate (KNbO3), Lithium Niobate (LiNbO3) etc. Direct piezoelectric effect – the production of electricity when stress is applied, Converse piezoelectric effect – the production of stress and/or strain when an electric field isapplied. M.S.Ramaiah School of Advanced Studies 3
  4. 4. Simple molecular model  Before subjecting the material to some external stress:  The centres of the negative and positive charges of each molecule coincide,  The external effects of the charges are reciprocally cancelled,  As a result, an electrically neutral molecule appears. M.S.Ramaiah School of Advanced Studies
  5. 5. Simple molecular model  After exerting some pressure on the material:  The internal structure is deformed,  That causes the separation of the positive and negative centres of the molecules,  As a result, little dipoles are generated. M.S.Ramaiah School of Advanced Studies 5
  6. 6. Simple molecular model Eventually:  The facing poles inside the material are mutually cancelled,  A distribution of a linked charge appears in the material’s surfaces and the material is polarized,  The polarization generates an electric field and can be used to transform the mechanical energy of the material’s deformation into electrical energy. M.S.Ramaiah School of Advanced Studies 6
  7. 7. Energy HarvestingEnergy harvesting describes the process of changing parasitic mechanical energy, for instance ofa vibrating structure, into electrical energy. This energy is used for other purposes. For exampledriving an electrical circuit or for storage in a battery or a large capacitor. Energy harvesting is the process by which energy is derived from external sources andutilized to drive the machines directly, or the energy is captured and stored for future use. Some traditional energy harvesting schemes are solar farms, wind farms, tidal energyutilizing farms, geothermal energy farms and many more. With the advent of technology,utilization of these sources has increased. When viewed on a large scale, energy harvestingschemes can be categorized as shown in Table. M.S.Ramaiah School of Advanced Studies 7
  8. 8. Piezoelectric Energy Harvesting Piezoelectric Energy Harvesting comes under the category of Micro scale energy harvestingscheme. The energy harvesting via. Piezoelectricity uses direct piezoelectric effect. The phenomenonwill be clear from the diagrams shown below. Fig 1. Principle of direct piezoelectric effect Fig 2. Structure of a piezoelectric component M.S.Ramaiah School of Advanced Studies 8
  9. 9. Piezoelectric Energy HarvestingThe output voltage obtained from a single piezoelectric crystal is in milli volt range, whichis different for different crystals. And the wattage is in microwatt range. In order to achieve higher voltages, the piezoelectric crystals can be arranged in series.The energy thus obtained is stored in lithium batteries or capacitors. This is the workingprinciple behind piezoelectric energy harvesting system.SOURCES OF VIBRATION FOR CRYSTALA. POWER GENERATING SIDEWALKThe piezoelectric crystal arrays are laid underneathpavements, side walks and other high traffic areaslike highways, speed breakers for maximum voltagegeneration. The voltage thus generated from the arraycan be used to charge the chargeable Lithiumbatteries, capacitors etc. These batteries can be usedas per the requirement. M.S.Ramaiah School of Advanced Studies 9
  10. 10. Sources of vibration for crystalB. POWER GENERATING BOOTS OR SHOESAn idea is being researched by DARPA in the UnitedStates in a project called Energy Harvesting, whichincludes an attempt to power battlefield equipmentby piezoelectric generators embedded in soldiersboots. However, these energy harvesting sources byassociation have an impact on the body. DARPAseffort to harness 1-2 watts from continuous shoeimpact while walking were abandoned due to thediscomfort from the additional energy expended by aperson wearing the shoes. M.S.Ramaiah School of Advanced Studies 10
  11. 11. Sources of vibration for crystalC. GYMS AND WORKPLACESResearchers are also working on the idea of utilizing thevibrations caused from the machines in the gym. Atworkplaces, while sitting on the chair, energy can be stored inthe batteries by laying piezoelectric crystals in the chair. Also,the studies are being carried out to utilize the vibrations in avehicle, like at clutches, gears, seats, shock-ups, foot rests.D. MOBILE KEYPAD AND KEYBOARDSThe piezoelectric crystals can be laid down under the keys of a mobile unit and keyboards. For thepress of every key, the vibrations being created can be used for piezoelectric crystal and hence canbe used for charging purpose.E. FLOOR MATS, TILES AND CARPETSA series of crystals can be laid below the floor mats, tiles and carpets which are frequently uses atpublic places. M.S.Ramaiah School of Advanced Studies 11
  12. 12. Sources of vibration for crystalF. PEOPLE POWERED DANCE CLUBSIn Europe, certain nightclubs have already begun to power their night clubs, strobes and stereosby use of piezoelectric crystals. The crystals are laid underneath the dance floor. When a bulk ofpeople use this dance floor, enormous amount of voltage is generated which can be used to powerthe equipments of the night clubG. PIEZOELECTRIC WIND MILLThe piezoelectric wind mill consists of a fan with three blades to effectively capture the windflow. A disc is connected at the lower end of translator, such that whenever it moves upwards anddownwards, it compresses the piezoelectric crystals. Hence for different speeds of wind also, thatis for different frequencies, the Piezoelectric Wind mill may function. Hence, it has higherworkable bandwidth. The constant compression of piezoelectric crystals causes a huge amount ofenergy to be generated, which can drive the remotely placed low power consuming devices. M.S.Ramaiah School of Advanced Studies 12
  13. 13. Applications of piezoelectricity1. As sensing elementsDetection of pressure variations in the form of sound is the most common sensor application, e.g.piezoelectric microphones. Sound waves bend the piezoelectric material, creating a changing voltage.2. Ultrasound imagingPiezoelectric sensors are used with high frequency sound in ultrasonic transducers for medical imaging .For many sensing techniques, the sensor can act as both a sensor and an actuator. Ultrasonic transducers,for example, can inject ultrasound waves into the body, receive the returned wave, and convert it to anelectrical signal (a voltage).3. Sonar sensorsPiezoelectric elements are also used in the detection and generation of sonar waves. Applications includepower monitoring in high power applications such as medical treatment, sonochemistry and industrialprocessing etc.4. As chemical and biological sensorsPiezoelectric microbalances are used as very sensitive chemical and biological sensors. Piezo are alsoused as strain gauges. M.S.Ramaiah School of Advanced Studies 13
  14. 14. Applications of piezoelectricity5. In Music instrumentsPiezoelectric transducers are used in electronic drum pads to detect the impact of the drummer’s sticks.6. Automotive applicationAutomotive engine management systems use a piezoelectric transducer to detect detonation by samplingthe vibrations of the engine block. Ultrasonic piezosensors are used in the detection of acoustic emissionsin acoustic emission testing.7. Piezoresistive silicon devicesThe Piezoresistive effect of semiconductors has been used for sensor devices employing all kinds ofsemiconductor materials such as germanium, polycrystalline silicon, amorphous silicon, and singlecrystal silicon. Since silicon is today the material of choice for integrated digital and analog circuits theuse of Piezoresistive silicon devices has been of great interest. It enables the easy integration of stresssensors with Bipolar and CMOS circuits.8. PiezoresistorsPiezoresistors are resistors made from a Piezoresistive material and are usually used for measurement ofmechanical stress. They are the simplest form of Piezoresistive device. M.S.Ramaiah School of Advanced Studies 14
  15. 15. Applications of piezoelectricity5. In Music instrumentsPiezoelectric transducers are used in electronic drum pads to detect the impact of the drummer’s sticks.6. Automotive applicationAutomotive engine management systems use a piezoelectric transducer to detect detonation by samplingthe vibrations of the engine block. Ultrasonic piezosensors are used in the detection of acoustic emissionsin acoustic emission testing.7. Piezoresistive silicon devicesThe Piezoresistive effect of semiconductors has been used for sensor devices employing all kinds ofsemiconductor materials such as germanium, polycrystalline silicon, amorphous silicon, and singlecrystal silicon. Since silicon is today the material of choice for integrated digital and analog circuits theuse of Piezoresistive silicon devices has been of great interest. It enables the easy integration of stresssensors with Bipolar and CMOS circuits.8. PiezoresistorsPiezoresistors are resistors made from a Piezoresistive material and are usually used for measurement ofmechanical stress. They are the simplest form of Piezoresistive device. M.S.Ramaiah School of Advanced Studies 15
  16. 16. Conclusion Flexible piezoelectric materials are attractive for power harvesting applications because of their ability to withstand large amounts of strain. PZT materials that can convert the ambient vibration energy surrounding them into electrical energy. This electrical energy can then be used to power other devices or stored for later use. This technology has gained an increasing attention due to the recent advances in wireless and MEMS technology, allowing sensors to be placed in remote locations and operate at very low power. The need for power harvesting devices is caused by the use batteries as power supplies for these wireless electronics. M.S.Ramaiah School of Advanced Studies 16
  17. 17. References[1]. Tomasz G. Zielinski, “ Fundamentals of piezoelectricity”, Institute Of Fundamental TechnologicalResearch, Warsaw, Poland.[2]. Tanvi Dikshit, Dhawal Shrivastava, (February 25 , 2010),“ Energy Harvesting via Piezoelectricity”,ChameliDevi Institute of Technology and Management, School of Electronics, DAVV, Indore M.S.Ramaiah School of Advanced Studies 17
  18. 18. M.S.Ramaiah School of Advanced Studies 18
  19. 19. Sl.No Topic Max Marks Marks Awarded 1. Quality Of Slides 5 2. Clarity of subject 5 3. Presentation 5 4. Effort and Question 5 Handling Total Marks = 20 = M.S.Ramaiah School of Advanced Studies 19

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