OFF-RESONANCE FREQUENCY OPERATION FOR POWER TRANSFER IN A LOOSELY COUPLED AIR CORE TRANSFORMER
First Claim
1. An apparatus for inductively transmitting power to a back EMF generating device, said apparatus comprising:
- a loosely coupled air core transformer including a primary coil in a primary circuit and a secondary coil in a secondary circuit, wherein said primary coil has a first resonance frequency determined by a product of a primary inductance and a primary capacitance in said primary circuit;
an alternating current (AC) voltage supply that supplies alternating voltage at an operating frequency between 50% and 95% of said first resonance frequency; and
a back EMF generating device electrically coupled to said secondary coil.
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Accused Products
Abstract
A power transmission system includes a loosely coupled air core transformer having a resonance frequency determined by a product of inductance and capacitance of a primary circuit including a primary coil. A secondary circuit is configured to have a substantially same product of inductance and capacitance. A back EMF generating device (e.g., a battery), which generates a back EMF with power transfer, is attached to the secondary circuit. Once the load power of the back EMF generating device exceeds a certain threshold level, which depends on the system parameters, the power transfer can be achieved at higher transfer efficiency if performed at an operating frequency less than the resonance frequency, which can be from 50% to 95% of the resonance frequency.
25 Citations
34 Claims
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1. An apparatus for inductively transmitting power to a back EMF generating device, said apparatus comprising:
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a loosely coupled air core transformer including a primary coil in a primary circuit and a secondary coil in a secondary circuit, wherein said primary coil has a first resonance frequency determined by a product of a primary inductance and a primary capacitance in said primary circuit; an alternating current (AC) voltage supply that supplies alternating voltage at an operating frequency between 50% and 95% of said first resonance frequency; and a back EMF generating device electrically coupled to said secondary coil. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of inductively transmitting power to a back EMF generating device comprising:
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providing an apparatus including a loosely coupled air core transformer including a primary coil in a primary circuit and a secondary coil in a secondary circuit, wherein said primary coil has a first resonance frequency determined by a product of a primary inductance and a primary capacitance in said primary circuit; and applying alternating voltage at an operating frequency between 50% and 95% of said first resonance frequency to said primary coil, wherein electrical power is transmitted to a back EMF generating device electrically coupled to said secondary coil through said loosely coupled air core transformer. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification