System and method for efficiently harvesting environmental energy

• US 9,385,626 B2
• Filed: 04/26/2012
• Issued: 07/05/2016
• Est. Priority Date: 04/29/2011
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Gasparini, Alessandro, Ramorini, Stefano, Membretti, Giorgio Massimiliano
• Primary Examiner(s): Wells, Kenneth B
• Assistant Examiner(s): Evans, James P
• Application Number:
  US13/456,814
• Publication Number:
  US 20120274144A1
• Time in Patent Office: 1,531 Days
• Field of Search: 307/80, 307/81, 290/1.R
• US Class Current: 1/1
• CPC Class Codes: B60C 23/041 Means for supplying power to the signal- transmitting means on the wheel
• CPC Class Codes: B60C 23/0411 Piezoelectric generators
• CPC Class Codes: H02M 7/2176 comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output

Abstract

A transducer converts energy coming from an energy source into an electrical signal for storage as electrical energy on a first storage element. A switch is selectively actuated to pass electrical energy from the first storage element to a second storage element. The selective actuation of the switch is driven by sensing electrical energy stored in the second storage element. The switch is closed when electrical energy in the second storage element is sensed to fall below a first threshold. The switch is opened when electrical energy in the second storage element is sensed to rise above a second threshold.

Claims

1. A system, comprising:

an energy-harvesting system for use in harvesting energy from movement of a support;

a transducer configured to convert energy coming from the energy-harvesting system into an electrical signal;

a first capacitive storage element coupled to an output of the transducer and configured to receive said electrical signal and store electrical energy,

a second capacitive storage element configured to store electrical energy; and

a switch coupled between the first and the second capacitive storage elements and operable to directly connect the first and second capacitive storage elements to one another to transfer electrical energy from the first capacitive storage element to the second capacitive storage element and, alternatively, uncouple the first and second capacitive storage elements from one another;

a DC-DC converter coupled between the second capacitive element and an electrical load, said DC-DC converter configured to receive electrical energy from the first capacitive storage element when the switch is closed and receive electrical energy from the second capacitive storage element when the switch is opened to produce a regulated output voltage; and

control logic having an output coupled to control said switch, said control logic configured to close the switch when the electrical energy stored in the second capacitive storage element is lower than a first threshold value, and further configured to open the switch when the electrical energy stored in the second capacitive storage element is higher than a second threshold value.

2. The system according to claim 1, wherein the first capacitive storage element comprises a first conduction terminal and a second conduction terminal, wherein the second capacitive storage element comprises a first conduction terminal and a second conduction terminal, wherein the second conduction terminals of the first and second capacitive storage elements are connected to a common reference terminal, wherein the first conduction terminals of the first and second capacitive storage elements are directly connected to respective terminals of the switch in such a way that, when the switch is operated to electrically couple the first and second capacitive storage elements, the respective first conduction terminals of the first and second capacitive storage elements are directly connected to one another.

3. The system according to claim 1, wherein said first capacitive storage element has an electrical energy storage capacity greater than that of said second capacitive storage element.

4. The system according to claim 1, wherein the control logic comprises:

a comparator with hysteresis configured to receive on a first input a first comparison signal indicative of electrical energy stored in the second capacitive storage element, and receive on a second input a second predefined comparison signal, and supply at the output a third comparison signal indicative of a result of a comparison between the first and second comparison signals;

a control and driving circuit configured to receive the third comparison signal and, on the basis of the third comparison signal, control opening or closing of the switch.

5. The system according to claim 1, wherein the electrical signal generated by the transducer is an AC voltage signal, the system further comprising a scavenging interface having an input connected to the transducer and an output connected to the first capacitive storage element, the scavenging interface configured to receive at an input the electrical signal and generate at an output a first intermediate DC signal to charge the first capacitive storage element.

6. The system according to claim 5, the DC-DC converter further configured to accept a voltage signal having a value lower than a maximum value, and the second capacitive storage element being configured in such a way that the difference of potential that, in use, is set up across its terminals has a value lower than said maximum value.

7. The system according to claim 1, wherein said support is a means of transport.

8. The system according to claim 1, wherein said transducer is chosen from the group consisting of:

electrochemical transducer, electromechanical transducer, electroacoustic transducer, electromagnetic transducer, photoelectric transducer, electrostatic transducer, thermoelectrical transducer.