Wind Energy Harvesting System - Energy Harvesting Autonomous Sensor Systems - page 61

Voltage (V)

Main : 25 k 50 s/div

2.8 V

V cap

3

2.75 V

2

2.55 V

1 I cap

0 50 100 150 200 250 300 350 400 Time (sec)

V in

Without WEH and MPPT
Discharge Time = 275 sec

With WEH and MPPT
Charge Time = 225 sec

FIGURE 2.23
Performance comparison between a conventional sensor node and a WEH sensor node.

Main : 25 k 50 s/div

Voltage (V)

3

2

V cap

1

I cap

0 50 100 150 200 250 300 350 400 Time (sec)

V in

Without
WEH
and
MPPT

With WEH
Without MPPT

With WEH and MPPT

FIGURE 2.24
Operation of a sensor node at a light wind speed of 2.3 m/s.