Non-stationary multi-frequency vibration energy harvesting with tunable electrical impedance

摘要

Harvesting energy from non-stationary, multi-frequency mechanical vibrations using a tunable electrical circuit. In an embodiment, an apparatus for converting vibrational energy to electrical energy includes a vibrational energy harvester having a transducer for generating time-varying electrical signals in response to environmental vibration; at least one power storage device; a switching network operably coupled between the transducer of the vibrational energy harvester and the at least one power storage device, wherein the switching network includes a plurality of switching elements each defining a switchable current path that is controlled by a control signal supplied to the respective switching element; and electronics configured to generate the control signals for supply to the switching elements of the switching network, the electronics including first circuitry, second circuitry, third circuitry, and fourth circuitry.

主权项

1. An apparatus for converting vibrational energy to electrical energy comprising:
a vibrational energy harvester having a transducer for generating time-varying electrical signals in response to environmental vibration; at least one power storage device; a switching network operably coupled between the transducer of the vibrational energy harvester and the at least one power storage device, wherein the switching network includes a plurality of switching elements each defining a switchable current path that is controlled by a control signal supplied to the respective switching element; and electronics configured to generate the control signals for supply to the switching elements of the switching network, the electronics including first circuitry, second circuitry, third circuitry, and fourth circuitry; wherein the first circuitry is configured to generate a measured signal representing magnitude and phase of current flowing through the switching elements of the switching network between the transducer of the energy harvester and the at least one power storage device; wherein the second circuitry is configured to generate a reference signal representing magnitude and phase of a current characteristic of a desired effective impedance of the switching network; wherein the third circuitry is configured to generate an error signal based on a difference between the reference signal and the measured signal; wherein the fourth circuitry is configured to generate the control signals supplied to the switching elements of the switching network, wherein the control signals are based on the error signal and control operation of the switching elements of the switching network such that the switching network provides the desired effective impedance; and wherein the second circuitry comprises a voltage sensing stage with an input operably coupled to an output of the transducer of the energy harvester to generate an output signal that represents measured voltage output by the transducer, and the second circuitry further comprises an integrator stage that integrates an output signal of the voltage sensing stage to generate a signal whose phase lags by 90 degree the phase of the signal output from the voltage sensing stage.