Energy Harvesting: A Survey of Sources and Technologies for Self-Powered Devices - Prof. J, Study notes of Electrical and Electronics Engineering

Download Energy Harvesting: A Survey of Sources and Technologies for Self-Powered Devices - Prof. J and more Study notes Electrical and Electronics Engineering in PDF only on Docsity! Abstract Historically, batteries have been the source of energy for most mobile, embedded and remote system applications. Now, with ubiquitous computing requirements in the fields of embedded systems, wireless sensor networks and low- power electronics such as MEMS devices, an alternative source of energy is required. Also with the limited capacity of finite power sources and the need for supplying energy for a lifetime of a system, there is a requirement for self- powered devices. The process of extracting energy from the surrounding environment is termed as energy harvesting. Energy harvesting, which originated from the windmill and water wheel, is widely being considered as a low- maintenance solution for a wide variety of applications. There are various forms of energy that can be scavenged, like thermal, mechanical, solar, acoustic, wind, and wave. This paper serves as a survey for identifying the sources of energy harvesting based on various technical papers available in the public domain. 1. Introduction With the wide advancements in the field of wireless sensor networks, some applications require the sensor nodes to have a long lifetime. Using conventional batteries is not always advantageous since they require human intervention to replace them. Hence, acquiring the electrical power needed to operate these devices is a major concern. An alternative type of energy source to conventional batteries must be considered. The electrical energy required to run these devices can be obtained by tapping the thermal, light, or mechanical energies available in the ambient environment. This process helps in providing unlimited energy for the lifespan of the electronic device. Therefore, the process of extracting energy from the ambient environment and converting it into consumable electrical energy is known as energy harvesting or power scavenging. The forms of typical ambient energies are sunlight, mechanical energy, thermal energy, and RF energy. The energy harvesting sources can be used to increase the lifetime and capability of the devices by either replacing or augmenting the battery usage [8, 24-26, 35, 48]. The devices powered by energy harvesters can be used to provide vital information on operational and structural circumstances by placing them in inaccessible locations [45]. There is an increasingly volume of research carried out on energy harvesting [1-72]. This paper is a survey of various technical papers on energy harvesting. We identify the various sources of energy available for harvesting and describe the work carried out by researchers. 2. Sources of Energy Harvesting The classification of energy harvesting can be organized on the basis of the form of energy they use to scavenge the power. For example piezoelectric harvesting devices scavenge mechanical energy and convert it into usable electrical energy. The various sources for energy harvesting are wind turbines, photovoltaic cells, thermoelectric generators and mechanical vibration devices such as piezoelectric devices, electromagnetic devices [45]. Table 1 shows some of the harvesting methods with their power generation capability [5]. Table 1: Energy Harvesting Sources [5] Harvesting Method Power Density Solar Cells 15mW/cm3 Piezoelectric 330µW/cm3 Vibration 116µW/cm3 Thermoelectric 40µW/cm3 The general properties to be considered to characterize a portable energy supplier are described by Fry, et al. [18]. The list includes electrical properties such as power density, maximum voltage and current; physical properties such as the size, shape and weight; environmental properties such as water resistance and operating temperature range; as well as operational and maintenance properties. Sufficient care should be taken while using the energy harvesters in the embedded systems to improve the performance and lifetime of the system. 3. Mechanical Vibration When a device is subjected to vibration, an inertial mass can be used to create movement. This movement can be converted to electrical energy using three mechanisms: piezoelectric, electrostatic and electromagnetic. The form of energy utilized here is the mechanical energy. A Survey of Energy Harvesting Sources for Embedded Systems Sravanthi Chalasani James M. Conrad Electrical and Computer Engineering Electrical and Computer Engineering University of North Carolina at Charlotte University of North Carolina at Charlotte schalasa@uncc.edu jmconrad@uncc.edu 3.1 Piezoelectric Materials These materials convert mechanical energy from pressure, vibrations or force into electricity. They are capable of generating electrical charge when a mechanical load is applied on them. This property of piezoelectric materials is considered by the researchers to develop various piezoelectric harvesters in order to power different applications [2, 10, 13, 33, 34, 37, 69, 70]. Due to their inherent ability to detect vibrations, piezoelectric materials have become a viable energy- scavenging source. Currently a wide variety of piezoelectric materials are available and the appropriate choice for sensing, actuating, or harvesting energy depends on their characteristics. Some are naturally occurring materials such as quartz. Polycrystalline ceramic is a common piezoelectric material. Lead Zirconate Titanate (PZT) is being considered since it shows a high efficiency of mechanical to electrical energy conversion [23]. With their anisotropic characteristics, the properties of the piezoelectric material differ depending upon the direction of forces and orientation of the polarization and electrodes [8]. Using piezoelectric materials to harvest energy requires a mode of storing the energy generated. This means they can either implement a circuit used to store the energy harvested or a circuit developed to utilize the energy harvested in producing excess energy [57]. The energy harvested can be stored in rechargeable batteries instead of using capacitors to store the energy [16, 27, 66]. The attribute of common capacitors to discharge quickly makes them unsuitable as energy storage devices in computational electronics [57]. Umeda, et al. [66] used a piezo-generator made of a bridge rectifier and a capacitor to store the energy. This resulted in achieving a maximum efficiency of 35% that is three times that of the energy harvested from a solar cell [57]. A self-powered mechanical strain energy sensor designed by Elvin, et al. [16] illustrates a simple beam bending experiment conducted to produce electrical energy from the mechanical stress applied. Here a piezofilm sensor attached to a beam is used to generate the electrical signal. According to Glynne-Jones, et al. [19, 20], an energy- harvesting device is being developed where a thick film of piezoelectric layer is deposited on to a thin steel beam. When the beam is resonated, the piezoelectric material is deformed and electrical energy is generated. By changing the material used, the magnitude of power generated can be improved. This group continues to research in this area and is currently preparing a detailed study to evaluate both piezoelectric and magnet-coil based generators and their possible useful applications. The earliest example for extracting electrical energy from piezoelectric material is from the impact of dropping a steel ball bearing onto a piezoelectric transducer [8, 65]. This energy was then stored in a capacitor or a battery [66]. The recent work by Cavallier, et al. [11] explored the amount of energy generated when a nickel package is used to couple the mechanical impact on to a piezoelectric plate. Callaway and Edgar discuss the harvesting of the electrical energy with the help of piezoelectric materials where human activity is involved [9]. For example, a piezoelectric material such as polyvinylidene fluoride (PVDF) is attached to the heel of a shoe. When the shoe strikes the ground, the energy released is converted by the piezoelectric material into electric charge. This charge can be used for some high-end sneaker designs [30]. In their book on Wireless Sensor Networks [9], Callaway and Edgar also discuss an application where the piezoelectric generator is used commercially in a wireless light switch. The power generated with the toggling of the switch is used in a transmit-only wireless network node. This node communicates with a receive-only wireless node powered by the mains attached to the light. A study is currently underway to examine generating power by inserting piezoelectric devices within orthopedic implants [47]. The article on energy harvesting projects by Joseph [23] mentions that the current piezoelectric energy harvesting research falls into two key areas. One is developing optimal energy harvesting structures and the other is designing electrical circuits that are efficient enough to store the generated charge. The research carried out at The University of Pittsburgh focuses on the first area, where the goal is to create small, lightweight structures that couple efficiently to mechanical excitation and produce usable electrical energy. This team is concentrating on developing optimal devices which are capable of converting the ambient mechanical energy available into electrical energy. Recently, a new power-conditioning circuit for piezoelectric energy scavenging systems has been proposed. Ottman, et al. [40-41] offers a greatly improved efficiency over existing designs under sinusoidal vibration. This circuit uses a step-down converter and harvested more than four times the power of the same circuit when the converter was not used. More than 70 mW of power was harvested from the new system, which is sufficient to power a wireless sensor network node, even in continuous receive mode. Later a simplified converter was employed which helped in producing more power. This work can be considered as a prominent step in the usage of energy generated from using piezoelectric materials. The properties of piezoelectric materials vary with age, stress and temperature. The possible advantages of using piezoelectric materials are the direct generation of desired voltage since they do not need a separate voltage source and additional components. These generators are compatible with the MEMs. These generators are the simplest and can be used in force and impact-coupled harvesting applications [8, 58]. Some disadvantages are that piezoelectric materials are brittle in nature and sometimes allow the leakage of charge [67]. 3.2 Electrostatic (Capacitive) Energy Harvesting This type of harvesting is based on the changing capacitance of vibration-dependent varactors. Vibrations separate the plates of an initially charged varactor (variable capacitor), and mechanical energy is converted into electrical energy. Electrostatic generators are mechanical devices that produce electricity by using manual power [14, 46]. The basic operating principle is well explained by Engineering Conference Proceedings, Vancouver, BC, Canada, 1999, v 34. [18] Fry D N, Holcomb D E, Munro J K, Oakes L C, and Maston M J, “Compact Portable Electric Power Sources,” Report, Oak Ridge National Laboratory, ORNL/TM-13360, 1997. [19] Glynne-Jones P, El-hami M, Beeby S P, James E P, Brown A D, Hill M and White N M, “A vibration-powered generator for wireless Microsystems”, Proceedings on Smart Structures and Microsystems in International Symposium, HongKong, October 2000. [20] Glynne-Jones P and White N M, “Self-powered systems: a review of energy sources,” Journal of Sensor Review, 2001, v 21, pp 91-98. [21] Gross W, “Optical power supply for fibre-optic hybrid sensors,” Journal of Sensors and Actuators A, 1991, v 25-27, pp 475-480. [22] Huang W S, Tzeng K E, Cheng M C and Huang R S, “Design and fabrication of a vibrational micro-generator for wearable MEMS,” Proceedings of Eurosensors XVII, Guimaraes, Portugal, 2003, pp 695–697. [23] Joseph A D “Works in Progress-Energy Harvesting Projects,” IEEE Pervasive Computing, January-March 2005, pp.69-71. [24] Kansal A and Srivastava M B, “An Environmental Energy harvesting framework for Sensor Networks,” Proceedings of International Symposium on Low Power Electronics and Design (ISLPED ’03). ACM Press, 2003, pp 481-486. [25] Kansal A, Potter D and Srivastava M B, “Performance Aware Tasking for Environmentally Powered Sensor Networks,” Proceedings on the Measurement and Modeling of Computer Systems in Joint International Conference, ACM Press, 2004, pp. 223–234. [26] Kansal A and Srivastava M B, “Distributed Energy Harvesting for Energy Neutral Sensor Networks,” IEEE Pervasive Computing, v 4, January-March 2005. [27] Kasyap A, Lim J, Johnson D, Horowitz S, Nishida T, Ngo K, Sheplak M and Cattafesta L, “Energy Reclamation from a Vibrating Piezoceramic Composite Beam,” Proceedings of 9th International Congress on Sound and Vibration, 2002, Paper No. 271. [28] Kulah H and Najafi K, “An electromagnetic micro power generator for low-frequency environmental vibrations,” Micro Electro Mechanical Systems—17th IEEE Conference on MEMS (Maastricht), 2004, pp 237–240. [29] Kuntz W and Mores R, “Electrically insulated smart sensors: principles for operation and supply,” Journal of Sensors and Actuators A, 1991, v 25-27, pp 497-505. [30] Kymisis J, Paradiso K J and Gershenfeld N, “Parasitic power harvesting in shoes,” Proceedings of IEEE International Conference on Wearable Computing, 1998, pp 132-139. [31] Lawreence E E and Snyder G J, “A Study of Heat Sink Performance in Air and Soil for Use in a Thermoelectric Energy Harvesting Device,” Proceedings of the 21st International Conference on Thermoelectronics, Portland, OR, 2002, pp. 446–449. [32] Lee J B, Chen Z, Allen M G, Rohatgi A and Arya R, “ A miniaturized high-voltage solar cell array as an electrostatic MEMS power supply,” Journal of Microelectromechanical Systems, September 1995, v 4, pp 102-108. [33] Li W. J, Chan G M H, Ching N N H, Leong P H W and Wong H Y, “Dynamical modeling and simulation of a laser- micromachined vibration-based micro power generator,” International Journal of Nonlinear Science Simulation, 2000, v 1, pp 345–353. [34] Liu Y, Ren K L, Hofmann H F and Zhang Q, “Investigation of Electrostrictive Polymers for Energy Harvesting,” IEEE Transactions on Ultrasonics, ferroelectrics and Frequency control, December 2005, v 52, n 12, pp 2411-2417. [35] Meninger S, “A low power controller for a MEMS based energy converter,” M Sc Massachusetts Institute of Technology, 1999. [36] Meninger S, Mur-Miranda J, Lang J, Chandrakasan A, Slocum A, Schmidt M and Amirtharajah R, “Vibration to electric energy conversion,” IEEE Trans Very Large Scale Integration (VLSI) Systems, 2001, v 9, pp 64–76. [37] Mitcheson P D, Green T C, Yeatman E M and Holmes A S, “Architectures for Vibration-Driven Micro-Power Generators,” IEEE Journal of Microelectromechanical Systems, 2004, v 13, pp 429-440. [38] Miyazaki M, Tanaka H, Ono G, Nagano T, Ohkubo N, Kawahara T and Yano K, “Electric-energy generation using variable-capacitive resonator for power-free LSI: efficiency analysis and fundamental experiment,” ISLPED, 2003, pp 193–198. [39] Mizuno M and Chetwynd D, “Investigation of a resonance microgenerator,” Micromech. Microeng, 2003, v 13, pp 209– 216. [40] Ottman G K, Hofmann H F, and Lesieutre G A, “Optimized piezoelectric energy harvesting circuit using step-down converter in discontinuous mode,” IEEE 33rd Annual Power Electronics Specialists Conference, 2002, v 4, pp 1988–1994. [41] Ottman G K, Hofmann H F, Bhatt A C, and Lesieutre G A “Adaptive piezoelectric energy harvesting circuit for wireless remote power supply,” IEEE Transactions Power Electronics, September 2002, v 17, n 5, pp 669–676. [42] Paradiso J A and Starner T, “Energy Scavenging for Mobile and Wireless Electronics,” Pervasive Computing, IEEE CS and IEEE ComSoc, January-March 2005, pp 18-27. [43] Paradiso J A, “Systems for Human-Powered Mobile Computing,” Proceedings of the 43rd annual conference on Design Automation, July 2006, pp 645-650. [44] Park C and Chou P H, “Power utility maximization for multiple-supply systems by a load-matching switch,” Proceedings of ACM/IEEE International Symposium on Low Power Electronics and Design, 2004, pp 168–173. [45] Park G, Farrar C R, Todd M D, Hodgkiss W and Rosing T, “Energy Harvesting for Structural Health Monitoring Sensor Networks,” Technical Report, Los Alamos National Laboratories, LA, February 2007. [46] Peano F and Tambosso T, “Design and optimisation of a MEMS electret-based capacitive energy scavenger,” Journal of Microelectromechanical Systems, 2005, v 14, pp 435–529. [47] Platt S R, Farritor S, Garvin K and Haider H, “The use of piezoelectric ceramics for electric power generation within orthopedic implants,” IEEE/ASME Transactions Mechatron, 2005, v 10, pp 455–461. [48] Rahimi M, Shah H, Sukhatme G S and Estrin D, “Studying the feasibility of Energy harvesting in a mobile sensor network,” Proceedings of IEEE International Conference on Robotics and Automation, 2003, pp 19-24. [49] Raghunathan V, Kansal A, Hsu J, Friedman J and Srivastava M, “Design Considerations for Solar Energy Harvesting Wireless Embedded Systems,” Fourth IEEE/ACM International Conference on Information Processing in Sensor Networks, April 2005. [50] Ross J N, “Optical power for sensor interfaces,” Journal of Measurement Science and Technology, 1992, v 3, pp 651-655. [51] Roundy S, Wright P and Pister K, “Micro-electrostatic vibration-to-electricity converters,” Proceedings, IMECE, 2002, pp 1–10. [52] Roundy S J, “Energy Scavenging for Wireless Sensor Nodes with a Focus on Vibration to Electricity Conversion,” Ph.D. Dissertation, Department of Mechanical Engineering, University of California, Berkeley, 2003. [53] Rowe M D, Min G, Williams S G, Aoune A, Matsuura K, Kuznetsov V L, and Fu L W, “Thermoelectric Recovery of Waste Heat – Case Studies,” Proceedings of the 32nd Intersociety Energy Conversion Engineering Conference, Honolulu, HI, July 27–Aug 1st 1997, pp 1075–1079. [54] Shearwood C and Yates R B, “Development of a resonant electromagnetic micro-generator”, electronic letters, 1997, v 33 n 22, pp 1883-1884. [55] Snarski S R, Kasper R G and Bruno A B, “ Device for electro- magnetohydrodynamic (EMHD) energy harvesting,” Proceedings of the SPIE, 2004, v 5417, pp 147-161. [56] Sodano H A, Dereux R, Simmers G E, and Inman D J, “Power Harvesting Using Thermal Gradients for Recharging Batteries,” Proceedings of 15th International Conference on Adaptive Structures and Technologies, Bar Harbor, ME, October 25–27 2004 [57] Sodano H A, Inman D J, and Park G., “A Review of Power Harvesting from Vibration Using Piezoelectric Materials,” The Shock and Vibration Digest, 2004, v 36, pp. 197–205. [58] Sodano H A, Inman D J and Park G, “Comparison of Piezoelectric Energy Harvesting Devices for Recharging Batteries,” Journal of Intelligent Material Systems and Structures. 2005, v 16, pp 799-807. [59] Sodano H A, Simmers G E, Dereux R, and Inman D J, “Recharging Batteries using Energy Harvested from Thermal Gradients,” Journal of Intelligent Material Systems and Structures, January 1, 2007, v 18, pp 3 - 10. [60] Sterken T, Baert K, Puers R and Borghs S “Power extraction from ambient vibration,” Proceedings of 3rd Workshop on Semiconductor Sensors and Actuators, November 2002, pp 680–683. [61] Sterken T, Fiorini P, Baert K, Borghs G and Puers R, “Novel design and fabrication of a MEMS electrostatic vibration scavenger,” Power MEMS Conference, Kyoto, Japan, 2004, pp 18–21. [62] Staley M E and Flatau A B, “Characterization of energy harvesting potential of Terfenol-D and Galfenol,” Proceedings of SPIE, 2005, pp 630-640. [63] Tashiro R, Kabei N, Katayama K, Tsuboi F and Tsuchiya K, “Development of an electrostatic generator for a cardiac pacemaker that harnesses the ventricular wall motion,” Journal on Artifcial Organs, 2002, pp 239–245. [64] Tashiro R, Kabai N, Katayama K, Ishizuka Y, Tsuboi F and Tsuchiya K, “Development of an electrostatic generator that harnesses the motion of a living body,” JSME International Journal Series C, 2000, c 43, pp 916–922. [65] Umeda M, Nakamura K and Ueha S, “Analysis of the transformation of mechanical impact energy to electric energy using piezoelectric vibrator,” Japan, Journal of Applied Physics, 1996, v 35, pp 3267–3273. [66] Umeda M, Nakamura K, and Ueha, S, “Energy Storage characteristics of a piezo-generator using impact induced vibration”, Journal of Applied Physics, 1997, v 36, pp 3146- 3151. [67] Wang L and Yuan F G, “Energy harvesting by magnetostrictive material (MsM) for powering wireless sensors in SHM,” SPIE Smart Structures and Materials & NDE and Health Monitoring, 14th International Symposium (SSN07), 18-22 March, 2007. [68] Warneke B, Last M, Liebowitz B and Pister K S J, “Smart Dust: communicating with a cubic-millimeter,” Journal of Computer, January 2001, v 34, pp 44-51. [69] White N M, Glynne-Jones P and Beeby S, “A novel thick- film piezoelectric micro-generator,” Smart Material Structures, August 2001, v 10, pp 850–852. [70] Williams C B and Yates R B, “Analysis of a micro-electric generator for microsystems,” in Proceedings of Solid-State Sensors and Actuator and in Eurosensors IX. Transducers, 1995, v 1, pp 369–372. [71] Williams C B, Pavic A, Crouch R S, and Wood R C, “Feasibility study of vibration-electric generator for bridge vibration sensors,” IMAC-Proceedings 16th International Modal Analysis Conference, 1998, v 32, pp 1111-1117. [72] http://energyscavenging.anu.edu.au/bibliography.php