US 5,703,474 A · Power transfer of piezoelectric generated energy

Abstract

The electric energy generated by a piezoelectric device (PEG), when mechanically stressed, is transferred from the PEG to a storage element (e.g., a capacitor or a battery) by selectively coupling an inductor in the conduction path between the PEG and the storage element. In one embodiment, the transfer of energy is optimized by allowing the amplitude of the electric signal to reach a peak value before transferring the electrical energy via an inductive network to a capacitor or a battery for storage. Electrically, the PEG is operated without a significant loading (e.g., essentially open circuited) when the amplitude of the voltage generated by the PEG is increasing. When the amplitude of the voltage has peaked, or reached a predetermined value, the electrical energy generated by the PEG is coupled to an inductive-capacitive network for absorbing and storing the energy produced by the PEG.

Claims24

Dependent claims

A combination comprising:

a piezoelectric generator (PEG) having first and second terminals across which an alternating current (AC) electrical signal is generated when the PEG is stressed;
rectifying means having an input means coupled across said first and second terminals of said PEG and having an output means for producing thereat a rectified output signal corresponding to said generated AC electrical signal;
means connecting a switch means in series with an inductor and a charge storage means across the output means of the rectifying means;
and
enabling means coupled to said switch means for selectively enabling said switch means, said enabling means including means for sensing the amplitude of the voltage at the output of the rectifying means and for sensing when the amplitude of the voltage has peaked and for then producing a turn-on pulse to enable said switch means and causing the inductor and charge storage means to be connected in circuit with said PEG for absorbing and storing the electrical energy generated by the PEG.

2 more elements

A combination comprising:

a piezoelectric generator (PEG) having first and second terminals across which an alternating current (AC) electrical signal is generated when the PEG is stressed;
said AC signal varying about a reference potential so as to increase above and decrease below said reference potential;
rectifying means having an input means coupled across said first and second terminals of said PEG and having first and second output terminals for producing thereat a rectified output signal corresponding to said generated AC electrical signal;
means coupling a selectively enabled switch means in series with an inductor and a charge storage means across the first and second output terminals of the rectifying means;
and
enabling means for sensing the voltage at the output of the rectifying means, said enabling means being coupled to said switch means and being responsive to said AC signal attaining a certain level for enabling said switch means and causing the inductor and charge storage means to be connected in circuit with said PEG for absorbing and storing the electrical energy generated by the PEG, and said switch means being disabled, within a first time period of being enabled, for removing the loading effect of the inductor and storage means and enabling the maximum amplitude of the signal produced between said first and second output terminals of said rectifying means to exceed the amplitude of the corresponding AC signal relative to said reference potential.

3 more elements

A combination comprising:

a piezoelectric generator (PEG) having first and second terminals across which an AC electrical signal is generated when the PEG is stressed;
a rectifying means having an input means coupled across said first and second terminals of said PEG and having first and second output terminals for producing thereat a rectified output signal corresponding to said generated electrical signal;
an inductor;
a capacitor;
a selectively enabled switching means;
means for coupling said selectively enabled switch means in series with said inductor and in series with said capacitor across said first and second output terminals of the rectifying means;
and
said selectively enabled switch means being connected between said inductor and said capacitor.

5 more elements

Dependencies are inferred from the claim text.

Power transfer of piezoelectric generated energy

Life of this patent

Power transfer of piezoelectric generated energy

Life of this patent

Abstract

Claims24