Application of Iron-Gallium Alloy - Energy Harvester and Sensors

1. Seminar topic 1 Application of Iron-Gallium Alloy- Energy Harvester and Sensors Jin-Hyeong YooUniversity of Maryland, College Park, MD 20742

2. Contents • Iron-Gallium Alloy – A New Magnetostrictive Material • Energy Harvester • Sensor Applications • Possible Applications for Soldier System

3. Energy Harvester: Solar Cell • Efficiencies • Crystalline silicon devices: 29% Max. • GaAs multi-junction devices: 42.3 % • Drawbacks • High cost • Needs large amount of space • Heavy weight - portability • It needs sun light K. Sangani, Eng. Technol., vol. 2 2007

5. Thermoelectric Generator • Average electric power of up to hundreds of milliwatts • Application tailoring achieved simply by varying number of thermocouples, deposition parameters, and substrate dimensions • Projected life longer than equivalent batteries • Provides power for the lifetime of the application • Adaptable to wide range of ambient conditions • Small temperature differences for miniature size scale • Poor thermodynamic efficiency This is a conceptual illustration of typical applications in representative environments where natural temperature differences exist. (Pacific Northwest National Lab.)

6. Ambient RF • Issues • Power level • Distance from source Mantiply et al. Pervasive Comput., vol. 4, 2005

7. Piezoelectric - Vibratory Macro-Fiber Composites www.smart-material.com Energy Harvesting Running Shoes Nathan S. Shenck, et al. IEEE Micro, Vol. 21, No. 3 (2001) Shoulder Strap Energy Harvesting Granstrom, et al. Smart Materials and Structures. 16 (2007)

8. Electromagnetic nPowerPEG.com Size: 9" tall, Top & Bottom Cylinders: 1'" diameter, Center Cylinder: 1.5" diameterWeight: 12 oz. (340 gram)Energy Storage Capacity: 1000mAh lithium Polymer batteryVoltage: 5V DC, 500mA output rangeWatts: 2.5 Watts Faraday Flashlights Amazon.com

9. Power Shirt (GIT) Image courtesy Zhong Lin Wang and XudongWang, GIT Regents professor Zhong Lin Wang holds a prototype microfiber nanogenerator composed of two fibers that rub together to produce a small electrical current. Many pairs of these fibers could be woven into a garment to produce a "power shirt.“ (2008)

10. “A change in dimensions exhibited by ferromagnetic materials when subjected to a magnetic field.” (Random House Dictionary) Documented by James Joule in 1842 Curie temperature quite high (~750°C for Fe81-Ga19) Effect will not “de-pole” Domain ordering returns without the need for poling after exceeding Curie temperature. What is Magnetostriction?

11. Actuation modeled by the “direct effect”: Sensing modeled by the “inverse effect”: 1-D Linearized Eqns where H=nI

12. DC or AC Magnetic Field l l + D l  Magnetostrictive Actuation The Direct Effect: The change in the dimensions of a ferromagnetic body caused by a change in its state of magnetization. H=nI

13. DC Magnetic Field l DB Magnetostrictive Sensing The Inverse Effect: The change in the magnetic state of a ferromagnetic body caused by a change in its state of stress. A B A H0=110 Oe B

14. Comparison of active materials • Smaller magnetizing coil • Smaller size • Higher power density • Ability to withstand shock loads • Bending structure

15. Magnetostrictive Electric Harvesting The Inverse Effect: The change in the magnetic state of a ferromagnetic body caused by a change in its state of stress.

16. Galfenol as Energy Harvester Galfenol has high permeability and high saturation magnetization  We expect high energy output! High Magnetic Efficiency ~2500 Gauss/ppm High Saturation Magnetization ~1.6 Tesla Strain

17. Galfenol Energy Harvester Pickup Coil Conceptual diagram On a vibration stage Al beam Pickup coils Galfenol beam Magnet

18. Mechanical Response of Beam Galfenol Harvester 2” Aluminum (t=0.05”) 1.5” Pickup Coil Mode Shape at 223Hz Galfenol (t=0.03”)

19. Magnetic Efficiency of Galfenol Piezomagnetic Constitutive Equation Sensor Coil Response Piezomagnetic Coupling Coefficient n= 1000 turns, A =b x t

20. Numerical Simulation H~50 Oe Strain range

21. Output Volts: Measured and Predicted

22. Output Power Test Setup Shaker Controller Vibration Command Accelerometer FFT analyzer Shaker Resistance Box

23. Output Power Test Results V Output volt and current at given resistance load (n=1000) R Galfenol-Al beam R = 1, 10, 36, 50, 100, 1000, infW a = 1.0, 2.0, 3.0, 4.0 g

24. Max. Output and Efficiency Sensor Coil M meff Vibration Harvester Pin

25. Applications for soldier system One early change by the US Army was to put multi-functional, low power, lightweight electronics on the wrist as shown in the picture and later work extensively employs energy harvesting. Manpack Antennas (Hascall-Denke)

26. Micro Gyro Sensor Development

27. Ω(t) GMR Magnetic sensor Fe79Ga21 Strips Sensing prong VD Actuator prong Permanent Magnet y x • Gyro Sensor Configuration Ω(t) Permanent Magnet Sensing prong Actuator prong VS VD y x Original Design Modified Design Modified thickness of prongs and sensor coil measurement

28. Tuning Fork Gyro Sensor • Basic Principle Coriolis Force • Excite one tuning fork leg to induce sympathetic vibration of second leg • Coriolis force will induce orthogonal deflection • Permeability will be changed by deflection of the Galfenol strip Maximize Dx to maximize F(t) z Ω(t) GMR sensor Dx Galfenol Strips VS VD y x (a) Drive mode (b) Sensing mode

29. Gyro Sensor Structure Driving Coil GMR Sensor GMR Sensor Holder Magnet • GMR sensor (NVE AA002-02) • 15 Oe max. • 0.9828Oe/V Adapter Sensor Assembly GMR sensor Assembly • JH Yoo, U Marschner and AB Flatau, Proceedings of SPIE, 5764-14, 2005.

30. Sensor Coil Output Spectrum Vibration Mode Test Ω(t) Permanent Magnet Sensing prong Actuator prong VS VD y x 0Hz 5Hz 20Hz

31. 1 Hz moment input 0.2 Hz moment input It has high sensitivity at low frequency!

32. Applications for Soldier System Indoor GPS compensation Hand Shaking Compensation Garmin ForetrexLightweight Wrist Mounted GPS Navigation

33. Wide Band Accelerometer Shaft & washers Sensor coil Hall sensor Sprung Mass Galfenol Cylinders Base • Alloy 79 – high permeable material as a flux return path. • 20 g of sprung mass, 0.3 Tesla permanent magnet • 3 Galfenol cylinders were tested (1/8”, 1/16”, and 1/32” wall thickness, ¼” long)

34. Single Crystal-Like Galfenol Patch placed on the surface of Aluminum Shaft at 45 ° with bias magnet Hall effect voltage vs. strain measured from strain gage at 45° on shaft Non-Contact Torque Measurement using Galfenol Galfenol Patch Hall Sensor Bias Magnet D. Douglas, SM Na, JH Yoo and AB Flatau, SPIE Smart Structures and Materials, 2010

35. Rotational Test 1/8 HP 30 rpm geared driving motor 220 inch-lbs torque 1/10 HP brake motor 1.8 inch-lbs torque Rotational Test Setup Brake Motor Hall Sensor Commercial Torque Sensor Driving Motor D. Douglas, SM Na, JH Yoo and AB Flatau, SPIE Smart Structures and Materials, 2010 Patch bonded to shaft

36. Bias magnet mounted with hall sensor Rotational Test Results Bias Magnet Hall Sensor Galfenol Patch corner 1 corner 2 Rotation Galfenol patch corner 1 passing under hall sensor Galfenol patch corner 2 passing under hall sensor

37. Summary: Advantage of Galfenol Sensor • Shock tolerable structural sensor • No energy input needed with • sensor coil (Green) • Easy to design • High sensitivity @ high frequency • Harsh condition application