PIEZOELECTIRC ENERGY HARVESTING SYSTEM WITH FREQUENCY MISMATCH TOLERANCE
First Claim
1. An impedance matching circuit, for use with a piezotransducer that can produce an output voltage waveform in response to a mechanical input stimulus and with an energy storage circuit that can harvest energy from the output voltage waveform, wherein the piezotransducer includes a parasitic capacitor, the impedance matching circuit comprising:
- an inductor configured to be coupled in parallel with the parasitic capacitor;
a peak and valley detection circuit configured to detect output voltage waveform peaks and valleys;
a first switch circuit configured to bias flip the output voltage waveform at a selectable first time relative to a detected peak and at a selectable first time relative to a detected valley;
a second switch circuit configured to couple the inductor to the energy storage circuit at a selectable second time following each output voltage bias flip;
an energy monitoring circuit that includes a voltage detector configured to provide an indication of energy flow from the inductor to the energy storage circuit following each output voltage bias flip; and
a maximum power point tracking (MPPT) circuit configured to select the first time and the second time based at least in part upon the indicated energy flow.
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Accused Products
Abstract
An impedance matching circuit is provided for use with a piezotransducer that includes a parasitic capacitor comprising: an inductor coupled in parallel with the parasitic capacitor; a peak and valley detection circuit configured to detect output voltage waveform peaks and valleys; a first switch circuit configured to bias flip the output voltage waveform at a selectable first time relative to a detected peak and at a selectable first time relative to a detected valley; a second switch circuit configured to couple the inductor to the energy storage circuit at a selectable second time following each output voltage bias flip; an energy monitoring circuit to provide an indication of energy flow from the inductor to the energy storage circuit following each output voltage bias flip; and a maximum power point tracking (MPPT) circuit configured to select the first time and the second time based at least in part upon the indicated energy flow.
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Citations
20 Claims
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1. An impedance matching circuit, for use with a piezotransducer that can produce an output voltage waveform in response to a mechanical input stimulus and with an energy storage circuit that can harvest energy from the output voltage waveform, wherein the piezotransducer includes a parasitic capacitor, the impedance matching circuit comprising:
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an inductor configured to be coupled in parallel with the parasitic capacitor; a peak and valley detection circuit configured to detect output voltage waveform peaks and valleys; a first switch circuit configured to bias flip the output voltage waveform at a selectable first time relative to a detected peak and at a selectable first time relative to a detected valley; a second switch circuit configured to couple the inductor to the energy storage circuit at a selectable second time following each output voltage bias flip; an energy monitoring circuit that includes a voltage detector configured to provide an indication of energy flow from the inductor to the energy storage circuit following each output voltage bias flip; and a maximum power point tracking (MPPT) circuit configured to select the first time and the second time based at least in part upon the indicated energy flow. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An energy harvesting system comprising:
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a piezotransducer configured to produce an output voltage waveform in response to a mechanical input stimulus, wherein the piezotransducer includes a parasitic capacitor; an energy storage circuit that can harvest energy from the output voltage waveform; an inductor configured to be coupled in parallel with the parasitic capacitor; a peak and valley detection circuit configured to detect output voltage waveform peaks and valleys; a first switch circuit configured to bias flip the output voltage waveform at a selectable first time relative to a detected peak and at a selectable first time relative to a detected valley; a second switch circuit configured to, at a selectable second time following each output voltage bias flip, couple the inductor to the energy storage circuit; an energy monitoring circuit that includes a voltage detector configured to provide an indication of energy flow from the inductor to the energy storage circuit following each output voltage bias flip; and a maximum power point tracking (MPPT) circuit configured to select the first time and the second time based at least in part upon the indicated energy flow. - View Dependent Claims (17)
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18. A method to capture energy from a piezotransducer configured to produce an output voltage waveform in response to a mechanical input stimulus, wherein the piezotransducer includes a parasitic capacitor and wherein the parasitic capacitor is coupled in parallel with an inductor comprising:
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bias flipping the output voltage waveform at times leading or lagging the output waveform peaks and at times leading or lagging the output waveform valleys; coupling the inductor to an energy storage device following each bias flip; determining an amount of energy captured by energy storage device during each coupling of the inductor to the energy storage device; and determining the leading or lagging times based at least in part upon the amount of energy captured during each coupling of the inductor to the energy storage device. - View Dependent Claims (19, 20)
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Specification