Electromechanical generator for, and method of, converting mechanical vibrational energy into electrical energy

• US 20070210580A1
• Filed: 03/08/2006
• Published: 09/13/2007
• Est. Priority Date: 03/08/2006
• Status: Active Grant

• Current Assignee: Hitachi Rail Ltd. (Hitachi, Ltd.)
• Original Assignee: Perpetuum, Ltd. (Hitachi, Ltd.)
• Inventors: Roberts, Stephen, Chini, Behrooz
• Granted Patent: US 7,345,372 B2
• Time in Patent Office: Days
• US Class Current: 290/1.R
• CPC Class Codes: F03G 7/08 recovering energy derived from swinging, rolling, pitching or like movements, e.g. from the vibrations of a machine
• CPC Class Codes: H02K 7/1892 Generators with parts oscillating or vibrating about an axis
• CPC Class Codes: H02P 9/006 Means for protecting the generator by using control H02H7/06 takes precedence; control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10

Abstract

An electromechanical generator comprising an electromechanical device for converting mechanical vibrational energy into electrical energy, the electromechanical device having a vibratable mass adapted to resonate with an oscillation amplitude at a frequency and a regulator for regulating the oscillation amplitude to a value not greater than a maximum threshold.

Claims

1. An electromechanical generator comprising an electromechanical device for converting mechanical vibrational energy into electrical energy, the electromechanical device having a vibratable mass adapted to resonate with an oscillation amplitude at a frequency and a regulator for regulating the oscillation amplitude to a value not greater than a maximum threshold.

2. An electromechanical generator according to claim 1 wherein the regulator comprises at least one voltage regulator for an output voltage of the electromechanical device, the at least one voltage regulator being adapted to cause short circuiting of an output of the electromechanical device when the output voltage exceeds a threshold voltage.

3. An electromechanical generator according to claim 2 wherein the voltage regulator comprising at least one Zener diode.

4. An electromechanical generator according to claim 2 wherein the regulator comprises two voltage regulators connected across an alternating current electrical output of the electromechanical device, the two voltage regulators each having a predetermined breakdown voltage and being connected in series and in an opposite current configuration across the electrical output.

5. An electromechanical generator according to claim 2 wherein the regulator comprises a voltage regulator connected across a direct current electrical output of the electromechanical device, the voltage regulator having a predetermined breakdown voltage.

6. An electromechanical generator according to claim 2 wherein the regulator comprises two first voltage regulators connected across an alternating current electrical output of the electromechanical device, the two voltage regulators each having a predetermined breakdown voltage and being connected in series and in an opposite current configuration across the electrical output, a rectifier connected to the voltage regulators, and a second voltage regulator connected across a direct current electrical output of the rectifier, the second voltage regulator having a predetermined breakdown voltage.

7. An electromechanical generator according to claim 2 wherein the regulator comprises a rectifier connected across an alternating current electrical output of the electromechanical device, the rectifier incorporating a plurality of voltage regulators each having a predetermined breakdown voltage.

8. An electromechanical generator according to claim 1 further comprising a detector for detecting the oscillation amplitude, and a comparator for determining whether the detected oscillation amplitude is above a predetermined maximum threshold, and wherein the regulator is operable in response to the comparator.

9. An electromechanical generator according to claim 8 wherein the detector is adapted to detect an electrical output from the electromechanical device, and the comparator is adapted to compare the detected electrical output to a threshold value of electrical output corresponding to the predetermined maximum amplitude.

10. An electromechanical generator according to claim 9 wherein the detector is adapted to detect an alternating current and an alternating voltage outputted from the electromechanical device.

11. An electromechanical generator according to claim 10 wherein the comparator is adapted to calculate a value of the electromotive force generated by the electromechanical device, and to compare that value with a preset value of electromotive force.

12. An electromechanical generator according to claim 9 further comprising a rectifier for rectifying the electrical output of the electromechanical device, and wherein the detector is adapted to detect a direct current and a direct voltage outputted from the rectifier.

13. An electromechanical generator according to claim 9 further comprising a shunt impedance element, having variable impedance, connected across output terminals of the electromechanical device and wherein the regulator is adapted to adjust the impedance of the shunt impedance element thereby to regulate the oscillation amplitude.

14. An electromechanical generator according to claim 13 wherein the impedance of the shunt impedance element is relatively high when the oscillation amplitude is not greater than the predetermined maximum threshold, and the impedance of the shunt impedance element is relatively low when the oscillation amplitude is above the predetermined maximum threshold.

15. An electromechanical generator according to claim 8 wherein the detector is selected from one of an optical proximity device;

a magnetic proximity device;

a mechanical proximity device;

a piezoelectric device;

an electromagnetic induction device;

or a magnetostrictive device.

16. An electromechanical generator according to claim 8 wherein the regulator is adapted to provided a dynamic feedback control of the amplitude in response to the detected amplitude.

17. An electromechanical generator according to claim 16 wherein the dynamic feedback control is continuous or intermittent.

18. A method of converting mechanical vibrational energy into electrical energy using an electromechanical generator, the method comprising the steps of:

(a) providing an electromechanical generator comprising an electromechanical device for converting mechanical vibrational energy into electrical energy at an electrical output of the electromechanical device, the electromechanical device having a vibratable mass adapted to resonate with an oscillation amplitude at a resonant frequency;

(b) vibrating the electromechanical device thereby to vibrate the vibratable mass thereby to generate an output voltage at the electrical output; and

(c) controlling the output voltage to below a predetermined maximum threshold value by short circuiting the electrical output when the output voltage is above the predetermined maximum threshold thereby to regulate the oscillation amplitude to a value not greater than a predetermined maximum threshold value.

19. An electromechanical generator comprising an electromechanical device for converting mechanical vibrational energy into electrical energy, the electromechanical device having a vibratable mass adapted to resonate with an oscillation amplitude at a frequency, an electrical output for the electrical energy, and at least one voltage regulator for regulating an output voltage at the electrical output, the at least one voltage regulator being connected across the electrical output and being adapted to short circuit the electrical output of the electromechanical device when the output voltage exceeds a threshold voltage thereby to cause damping of the vibration of the vibratable mass.

20. An electromechanical generator comprising an electromechanical device for converting mechanical vibrational energy into electrical energy, the electromechanical device having a vibratable mass adapted to resonate with an oscillation amplitude at a frequency, the vibratable mass comprising a first element selected from the group consisting of at least one coil and at least one magnet, and the vibratable mass being arranged to vibrate relative to a second element of the electromechanical device selected from the group consisting of at least one magnet and at least one coil, respectively;

a detector for detecting an electrical output from the at least one coil of the electromechanical device;

a comparator for calculating a value of the electromotive force generated by the at least one coil of the electromechanical device, and to compare that value with a preset value of electromotive force;

a shunt impedance element, having variable impedance, connected across output terminals of the electromechanical device; and

a regulator, operable in response to the comparator, which is adapted to adjust the impedance of the shunt impedance element thereby to regulate the calculated value of the electromotive force to a value not greater than the preset value of electromotive force.