Power generation unit, electronic apparatus, transportation device, and method of controlling power generation unit
A power generation unit includes: a deforming member adapted to deform while switching a deformation direction; a piezoelectric device provided to the deforming member, and having a pair of electrodes; a displacement sensor adapted to detect a deformation amount of the deforming member, and then output deformation amount information as information related to the deformation amount; an inductor electrically connected to the piezoelectric device; a switch disposed between the piezoelectric device and the inductor; and a switch control section adapted to control the switch so as to set the pair of electrodes to a shorted state for a predetermined period of time when the deformation amount exceeds a predetermined level.
1. A power generation unit comprising:
a deforming member adapted to deform while switching a deformation direction;
a piezoelectric device provided to the deforming member, and having a pair of electrodes;
a displacement sensor adapted to detect a deformation amount of the deforming member, and then output deformation amount information as information related to the deformation amount;
an inductor electrically connected to the piezoelectric device;
a switch disposed between the piezoelectric device and the inductor; and
a switch control section adapted to control the switch so as to set the pair of electrodes to a shorted state for a predetermined period of time when the deformation amount exceeds a predetermined level.
2. The power generation unit according to claim 1 , wherein
in a period in which the deformation amount is lower than the predetermined level, the switch control section sets the switch to a connected state when the deformation direction of the deforming member is switched, and then sets the switch to a disconnected state when a time period corresponding to a half cycle of a resonance period calculated using a capacitive component of the piezoelectric device and an inductance of the inductor.
3. The power generation unit according to claim 1 , wherein
the deformation amount information corresponds to a magnitude of a displacement due to the deformation of the deforming member, and
the switch control section controls the switch to set the pair of electrodes to the shorted state for a predetermined period of time when the magnitude of the displacement exceeds a predetermined threshold value.
4. The power generation unit according to claim 1 , wherein
the deformation amount information corresponds to a magnitude of a displacement due to the deformation of the deforming member, and
the switch control section performs second-order differentiation on the magnitude of the displacement to thereby obtain an acceleration, and controls the switch to set the pair of electrodes to the shorted state for a predetermined period of time when a level of the acceleration exceeds a predetermined threshold level.
5. The power generation unit according to claim 1 , wherein
the displacement sensor is of an eddy current type.
6. The power generation unit according to claim 1 , wherein
the displacement sensor is of an optical type.
7. The power generation unit according to claim 1 , wherein
the displacement sensor is of an ultrasonic type.
8. The power generation unit according to claim 1 , wherein
the displacement sensor is of a capacitance type.
9. A battery comprising the power generation unit according to claim 1 .
10. A battery comprising the power generation unit according to claim 2 .
11. A battery comprising the power generation unit according to claim 3 .
12. A battery comprising the power generation unit according to claim 4 .
13. An electronic apparatus comprising the power generation unit according to claim 1 .
14. An electronic apparatus comprising the power generation unit according to claim 2 .
15. An electronic apparatus comprising the power generation unit according to claim 3 .
16. An electronic apparatus comprising the power generation unit according to claim 4 .
17. A transportation device comprising the power generation unit according to claim 1 .
18. A transportation device comprising the power generation unit according to claim 2 .
19. A transportation device comprising the power generation unit according to claim 3 .
20. A method of controlling a power generation unit including
a deforming member adapted to deform while switching a deformation direction,
a piezoelectric device provided to the deforming member,
a displacement sensor adapted to detect a deformation amount of the deforming member, and then output deformation amount information as information related to the deformation amount,
an inductor electrically connected to the piezoelectric device, and
a switch disposed between the piezoelectric device and the inductor, the method comprising:
acquiring the deformation amount information; and
controlling the switch to set the piezoelectric device and the inductor to a shorted state for a predetermined period of time when the deformation amount exceeds a predetermined value.