Energy Harvesting Applications for Efficient Power Management
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Discover energy harvesting methods & circuit collections for sensor nodes, lithium batteries, solar cells, and more. Learn how to maximize power transfer and store energy efficiently. Explore innovative solutions by Linear Technologies Corporation.
Energy Harvesting Applications for Efficient Power Management
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Presentation Transcript
Energy Harvesting Day 5: Energy Applications - Energy Conversion and Management Silicon April 19, 2013Paul NickelsbergOrchid Technologies Engineering and Consulting, Inc.www.orchid-tech.com
Energy Harvesting Review • Energy harvesting is the process of capturing trace amounts of naturally occurring energy from various sources. • Accumulating the Energy • Storing the Energy • Applying the Energy for Useful Purpose
Energy Applications EnergySource Energy Management EnergyApplication 3
Energy Applications • Sensor Node Power Requirements: • SupplyVoltage: Vs • ContinuousCurrent: Ic • Additional PulsedCurrent: Ip • Pulse Duration: tp • System On Time: ton • NumberofSequences: N • SequenceDuty Cycle: DC Total Energy Bill: Courtesy Linear Technologies Corporation 4
Energy Applications Whereisthesweetspotformaximum power transferbetweenSource andLoad? Whatisthetransferred power atthatpoint? Courtesy Linear Technologies Corporation 5
Energy Applications Storage Cap collectschargeduringSensor Idle State. Actsaslowimpedancesourcewhen Power isneeded. 1 2 Aux Cap collectschargebeforeenabling VOUT control Over source parameter control harvester input power e.g. Maximum power pointcontrol Adjustcurrenttokeeptheinputatthedesiredvoltage. EffectivelyraisestheinputresistanceoftheHarvesterwhentheloadisoverdrivingthesource. Knownas MPPC for Solar Cells. 3 Courtesy Linear Technologies Corporation Over time decouple output and input: e.g. Caps/battery to buffer energy 6
Energy Applications Circuit Collections Rechargeable Lithium Thin Film Battery Source: Cymbet Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 7
Energy Applications Circuit Collections Advanced Linear DevicesALD110902 Source: Advanced Linear Devices Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 8
Energy Applications Circuit Collections SeikoS-882Z Source: Seiko Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 9
Energy Applications Circuit Collections SeikoS-882Z Source: Seiko Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 10
Energy Applications Circuit Collections Source: Mide Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 11
Energy Applications Circuit Collections Solar Cell orTEG Source: Texas Instruments Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 12
Energy Applications Circuit Collections LTC3108/-1: Ultra-Low Voltage (20mV) Step-Up converter and Power Manager • Operates from inputs as low as 20mV • Alternate Fixed Output Voltages • Unique Resonant Power converter / Energy Harvester • Auxiliary LDO • Manages Energy storage between Reservoir and Main Cout or Batt • Compact Step-upTransformer • 3x4mm DFN or GN16 packages Courtesy Linear Technologies Corporation Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 13
Energy Applications Circuit Collections VOUT2: Switched VOUT Rectifier 20mV Vin Source VOUT: Main Output Digital Vout Select Compact Step-Up transformer Depletion mode MOSFET VSTORE: Energy Reservoir 3mA LDO: uController power Courtesy Linear Technologies Corporation VAUX: Intermediate Charge storage and IC bias supply Charge Control and Prioritizer Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 14
Energy Applications Circuit Collections LTC3588 PiezoelectricEnergy Harvester • Key Features: • Integrated rectifier converts piezo AC output to DC ( extremely low leakage ) • 500nA UVLO circuit allows input cap to be charged up before DC/DC enabled – ensures reliable startup • Synchronous step-down DC/DC operates over wide VIN and load current with high efficiency • Overvoltage shunt protects input – dumps excess energy to GND at VIN > 20V • 1uA (typ) no load ICC minimizes wasted energy at low vibration levels Courtesy Linear Technologies Corporation Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 15
Energy Applications Circuit Collections High Efficiency Solar Energy Harvester • Synchronous Boost Converter + LDO starts up at 250mV • Includes Maximum Power Point Control (MPPC), which adjusts the peak inductor current to maintain Vin at a programmed voltage • Operates from higher resistance sources than traditional boosts • Uses burst-mode architecture with variable Ipk and Ivalley Courtesy Linear Technologies Corporation Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 16
Energy Applications Circuit Collections LTC3105: Block Diagram Courtesy Linear Technologies Corporation Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 17
Energy Applications Circuit Collections • LTC3105 boosts the low solar panel output voltage to a higher voltage to allow charging • LTC4070 shunt battery charger limits the maximum battery voltage to 4.2V • NTC thermistor reduces the battery float voltage in 100mV steps at high temperatures • P-FET disconnects the load to prevent damaging the battery from over discharge Courtesy Linear Technologies Corporation Note: Circuits shown are for example purposes only. You must carefully verify circuitry used in your application. 18
Energy HarvestingAdditional Reading • Electrical Energy An Introduction 3rd Edition • Mohamed A. El-Sharkawi • The International System of Units (SI) • Catalog of Units 8th Edition, 2006 • Piezoelectric Energy HarvestingAlper Erturk / Daniel Inman (Wiley 2011) • Materials, Preparation, and Characterization inThermoelectrics, D.M. Rowe (CRC 2012) 19