Post on 30-Dec-2015
description
Chapter 18 - Novel RFID TechnologiesEnergy Harvesting for Self-powered Autonomous RFID
Systems
Figure 18.1 Micro-Wireless Dot™ - Courtesy, Axcess International
LF Coil100 - 150
kHz
Antenna860-960
MHz
Antenna315/433
MHz
EnergyAware
Processor
ProtocolAdaptiveFirmware
System-on-a-Chip
SerialPorts
Power Management
NVMemory
ADCDAC
SerialBus
Near-FieldLoad Modulation
Far-FieldTransceiver
Far-FieldBackscatter
GPIO
Table 18.1 RFID/Sensor life time
3 V100 µW
33.33 µA
40 ms4.8 mA
0.000576 Watt-sec200
8 sec0.12 Watt-sec
10 µA
86392 sec2.59 Watt-sec2.71 Watt-sec
7.52 hrs
Energy necessary for transmissions
Energy necessary for idle conditions/day
Current available from vibrations (i source )
Axcess Tag powered by batteryPower available from vibrations
Transmission of ID to receiver takesCurrent draw during transmission (i active )Energy necessary/transmission
Time required to gather this energy from vibrations/day (t 3 )
Number of transmissions/day
Idle state current draw (i sleep )
Idle state time/day (t 1 )
Total energy reqd (idle+transmission)/day
Transmission time/day (t 2 )
Figure 18.2 Block diagram of an EH sensor
EnergySource
EnergyTransducer
EnergyStorage
VoltageRegulator
A/DConverter
Processor
EnvironmentalSensor
WirelessTransceiver
PGM/DataMemory
Energy Harvesting Wireless Sensor
Power Management
Energy Storage
Energy Transducer
Table 18.2 Power densities of EH technologies
Energy Harvesting Source
Power Density (µW/cm3)
Information Source
Solar (Outdoors)15,000 - Direct Sun 150 - Cloudy Day
Commonly Available
Solar (Indoors) 6 - Office Desk ExperimentsVibrations 100 - 200 Roundy et. al.
Acoustic Noise 0.003 @ 75 dB 0.96 @ 100 dB
Theory
Daily Temp. Variation 10 TheoryTemp. Gradient 15 @ 10oC Stordeur & Stark, 1997Piezo Shoe Inserts 330 Starner, 1996
Figure 18.3 EH system for solar cells
DC-DC Converter
CsS1Load
Switching converter (buck or buck-boost) or Switched capacitor converter
Secondary battery (Thin film, lithium, NiMH, etc.) or Ultracapacitor
Figure 18.4 Solar panel V-I characteristics
1
10
100
1000
10000
100000
0 1 2 3 4 5 6
Cu
rren
t (u
A)
Voltage (V)
Full Sun (95000 lx)
3300 lx
300 lx
Figure 18.5 DC-DC buck-boost converter for solar EH
Figure 18.6 A thermoelectric transducer VI characteristics
Figure 18.7 Types of Vibration EH Transducers
ElectrostaticChange in capacitance causes either voltageor charge increase.
Shad Roundy et . al., 2002 Shad Roundy et. al., 2004
PiezoelectricStrain in piezoelectricmaterial causes a charge separation (voltage acrosscapacitor)
Vs
C Rs
Piezoelectric generator
ElectromagneticCoil moves through magnetic field causing current in wire.
Amirtharajah et. al., 1998
Figure 18.8 Piezoelectric conversion modes
Table 18.3 Common vibration sources
Vibration SourcePeak
Frequency (Hz)
Acceleration (m/s2)
Car Engine Compartment 200 12Base of 3-axis machine 70 10Door Frame (after door closes) 125 3Small Microwave Oven 121 2.5HVAC Office Vents 60 0.2 - 1.5Windows on Busy Road 100 0.7CD in Notebook PC 75 0.62nd Story Floor in Busy Office 100 0.2
Figure 18.9 Cantilever characteristics
Figure 18.10 Block diagram of a vibration energy harvesting system
Piezo-electric vibration
transducerVs Rectifier
DC/DCConverter
Load (Battery)
Csource Rsource
Vrect+
-Vbat
+
-
Figure 18.11 DC-DC buck-boost converter with battery load
VB1C1Vrect
+
-
Q1
Vctrl
VC2 C2L
D1
-
+B1
Irect Ibat
Figure 18.12 Vision for EH based Micro-Wireless Dot™ sensor
Flex Circuit Antenna, Circuit Wiring
RF TransceiverCoils
Printed Passive Components
Barcode Label, Graphics, or Thin Film Solar Energy Harvesting Film
Thin-Film Renewable Charge Reservoirs
Piezoelectric MEMS Array & Wiring
Power Management
Figure 18.13 : Top view of the electrode patterns for cantilevers
of different sizes
Figure 18.14 MEMS cantilever – Courtesy, Texas MicroPower Inc
Table 18.4 Comparison of power densities
Author Device Effective Area (mm2)
Power, (μW)
Power density, (μWinch-2)
Power density, (μWinch-2g-1)
A (g) f (Hz)
Kim et al d33 PZT cantilever 0.0442 1 14596.41 1351.52 10.8 13.7k Shen et al d31 PZT cantilever 1.92 2.15 722.45 361.22 2.0 462.5 Marzencki et al d31 AlN cantilever 3.8 0.038 6.45 12.90 0.5 204 Jeon et al d33 PZT cantilever 0.027 1.01 24133.81 2234.61 10.8 13.9k Fang et al d31 PZT cantilever 0.1992 2.16 6995.72 6995.72 1.0 608 Marzencki et al d31 AlN cantilever 0.552 1.97 2302.48 575.62 4.0 1368 Renaud et al d31 PZT cantilever 1.845 40 13987.24 7361.70 1.9 -
Figure 18.15 Adaptive multi-source power management architecture
Optional Rectification
Tranducer DC/DC Converter
Energy Storage Device
PWM Controller
Solar/Vibrations/ Thermal, etc.
AC/DC Conversion
Vrect, Irect Vbat, Ibat
Rechargeable battery, Ultracapacitor, etc.