Device and method for harvesting energy from a power line magnetic field

1. In an energy harvesting device (CTH) for harvesting electrical energy from an electrical conductor installed in an electrical distribution system, the CTH being electrically connected to a current transformer (CT) having an electrical winding imposed on the electrical conductor, and wherein the CT receives electrical energy induced in the winding by a magnetic flux caused by the flow of an alternating current through the electrical conductor, the CT being electrically coupled to the winding for producing an induced electrical current which is converted into electrical energy for powering one or more ancillary electrical devices employed in the distribution system, the CTH including a voltage regulator configured to receive the induced current and produce a clamping voltage matched to a power curve of the CT; the improvement comprising the CTH further including a second and supplementary voltage regulator separate from the first said voltage regulator and which continuously operates to maximize the amount of electrical energy recovered from the current transformer.

2. The improvement of claim 1 in which the second voltage regulator of the CTH adjusts the clamped voltage in pre-determined steps to obtain optimum power recovery.

3. The improvement of claim 2 in which the second voltage regulator makes adjustments in response to monitored voltage and current values from the CT.

4. The improvement of claim 2 further including a microcontroller responsive to the monitored voltage and current values to have the second voltage regulator modify the voltage regulation point.

5. The improvement of claim 1 in which the second voltage regulator includes a switching regulator which converts recovered current from the CT into electrical energy used to power the ancillary electrical devices.

6. The improvement of claim 5 further including energy storage means for storing the electrical energy.

7. The improvement of claim 6 in which the energy storage means includes one of:

a battery;

an electrolytic capacitor;

a double layer electrolytic capacitor.

8. An energy harvesting device (CTH) for harvesting electrical energy from an electrical conductor installed in an electrical distribution system, the CTH being electrically connected to a current transformer (CT) having an electrical winding imposed on the electrical conductor, and wherein the CT receives electrical energy induced in the winding by a magnetic flux caused by the flow of an alternating current through the electrical conductor, the CT electrically coupled to the winding for producing an induced electrical current which is converted into electrical energy for powering one or more ancillary electrical devices employed in the distribution system, the CTH comprising:

a first voltage regulator circuit configured to receive the induced current and produce a clamping voltage matched to a power curve of the CT;

a second voltage regulator circuit separate from the first said voltage regulator circuit and continuously operating to maximize the amount of electrical energy recovered from the CT, the second voltage regulator circuit adjusting the clamped voltage in pre-determined steps by which optimum power recovery is achieved; and,

a microcontroller responsive to sensed voltage and current values to control the second voltage regulator circuit to modify the voltage regulation point.

9. The CTH of claim 8 in which the second voltage regulator circuit includes a switching regulator which converts the recovered current into electrical energy used to power the ancillary electrical devices.

10. The CTH of claim 8 further including energy storage means for storing the electrical energy.

11. The CTH of claim 10 in which the energy storage means includes one of:

a battery;

an electrolytic capacitor;

a double layer electrolytic capacitor.

12. In an energy harvesting device (CTH) for harvesting electrical energy from an electrical conductor installed in an electrical distribution system, the CTH electrically connected to a current transformer (CT) having an electrical winding imposed on the electrical conductor, and wherein the CT receives electrical energy induced in the winding by a magnetic flux caused by the flow of an alternating current through the electrical conductor, the CT electrically coupled to the winding for producing an induced electrical current which is converted into electrical energy for powering one or more ancillary electrical devices employed in the distribution system, the CTH including a voltage regulator circuit configured to receive the induced current and produce a clamping voltage matched to a power curve of the CT:

a method for continuously maximizing the amount of electrical energy recovered from the current transformer for powering the ancillary electrical devices, the method including: monitoring, by a microcontroller, sensed voltage and current values of the CT; and,

adjusting, by a second CTH voltage regulator circuit separate from the first voltage regulator circuit of the CTH, the clamping voltage in response to commands from the microcontroller.

13. The method of claim 12 wherein the second voltage regulator circuit adjusts the clamped voltage in pre-determined steps in response to inputs from the microcontroller so to achieve an optimum power recovery.

14. The method of claim 12 further including converting the recovered current into electrical energy used to power the ancillary electrical devices.

15. The method of claim 14 wherein the conversion is performed by a switching regulator of the second voltage regulator circuit.

16. The method of claim 14 further including storing the electrical energy used to power the ancillary electrical devices.