Environmental Engineering Reference
In-Depth Information
FIGURE 6.10
Experimental testing platform for the magnetic energy harvester.
Once the induced AC voltage
V
emf
of the stray magnetic energy harvester
was input to the voltage doubler, the voltage doubler circuit output a DC and
doubled voltage. By doing so, the design of the power management would
be simpler. The voltage from the secondary coil of the transformer was rec-
tified in the voltage doubler, and then electric charge was accumulated on
the electrolytic storage capacitor C1 of the power storage and supply circuit.
The charging and discharging voltages of C1 were 4 and 6.72 V, respectively
(as shown in
Figure 6.12
)
. The amount of electrical energy stored in the elec-
trolytic capacitor C1 with capacitance value of 47
F was calculated to be
685
J.
For each 12-bit digital data, the time taken for one transmission was 20 ms,
that is, 10 ms of active time and 10 ms of idle time. During the active trans-
mission time, the supply voltage and current of 3.3 V and 4 mA, respectively,
were consumed by the RF transmitter load. As for the remaining time of 10
ms, the RF transmitter load was operating in idle mode, which means that
a very minimal amount of energy would be consumed, so it is reasonable to
exclude the power being consumed by the RF transmitter load during the
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