System and method for automatic tuning of a magnetic field generator
First Claim
1. An automatic tuning system for a magnetic field generator comprising:
- a processor;
a power source;
a tuned circuit comprising a magnetic field generating inductor (L) and an adjustable capacitor (C), the values of the L and C establishing the tuned circuit resonant frequency,a power amplifier coupled to the power source, said power amplifier having an output coupled to and adapted to drive the tuned circuit;
a reference frequency oscillator circuit coupled to the power amplifier so as to cause the power amplifier to generate an output signal at a reference frequency; and
a sense circuit coupled to the power amplifier and adapted to sense a signal indicative of the power delivered by the power amplifier to the tuned circuit and provide thereby a power level signal relating to such power delivered, whereby the power delivered by the power amplifier is a function of the resonant frequency of the tuned circuit, and wherein the processor monitors the power level signal and causes the adjustable capacitor to be adjusted to a capacitance value that maximizes the power delivered by the power amplifier.
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Accused Products
Abstract
An automatic tuning system for a magnetic field generating tuned circuit includes a processor configured to maintain the resonant frequency of a tuned circuit equal to a reference frequency. The tuned circuit is driven by a power amplifier whose output provides an amplified signal at the reference frequency. The tuned circuit includes a magnetic field generating inductor and a bank of individually switchable capacitors controlled by the processor capable of adding and removing the respective capacitances to and from the tuned circuit. The inductor includes a Faraday shield to shield the tuned circuit from the influence of electric fields. A power sense circuit monitors the power delivered by the power amplifier to the tuned circuit and the processor sequentially switches the capacitors in a binary progression format to achieve maximum power delivery indicative of conforming the resonant frequency of the tuned circuit to the reference frequency. In an alternate embodiment of the invention, the inductor includes a plurality of taps that provide individually selectable inductance values available for use in the process of conforming the resonant frequency of the tuned circuit to the reference frequency. In further alternate embodiments, the variable capacitor is in the form of a motor driven variable capacitor and the tuning sequence relies on a phase locked loop using the phase of a reference frequency signal and the phase of the inductor current as control parameters.
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Citations
61 Claims
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1. An automatic tuning system for a magnetic field generator comprising:
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a processor; a power source; a tuned circuit comprising a magnetic field generating inductor (L) and an adjustable capacitor (C), the values of the L and C establishing the tuned circuit resonant frequency, a power amplifier coupled to the power source, said power amplifier having an output coupled to and adapted to drive the tuned circuit; a reference frequency oscillator circuit coupled to the power amplifier so as to cause the power amplifier to generate an output signal at a reference frequency; and a sense circuit coupled to the power amplifier and adapted to sense a signal indicative of the power delivered by the power amplifier to the tuned circuit and provide thereby a power level signal relating to such power delivered, whereby the power delivered by the power amplifier is a function of the resonant frequency of the tuned circuit, and wherein the processor monitors the power level signal and causes the adjustable capacitor to be adjusted to a capacitance value that maximizes the power delivered by the power amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. In an automatic tuning system for a magnetic field generator comprising, a tuned circuit comprising a magnetic field generating inductor (L) and an adjustable capacitor (C), the values of the L and C establishing a tuned circuit resonant frequency, a power amplifier having an output coupled to and adapted to drive the tuned circuit, the power amplifier providing, at said output, an amplified signal at a preselected reference frequency, the method of tuning the tuned circuit comprising the steps of:
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(1) adjusting the adjustable capacitor to a predetermined initial capacitance value; (2) measuring the power delivered by the power amplifier to the tuned circuit; (3) incrementally changing the capacitance value of the adjustable capacitor; (4) repeating steps 2 and 3 for all possible capacitance values of the adjustable capacitor; and (5) readjusting the adjustable capacitor to have the capacitance value that maximizes the power (max a power point) delivered to the tuned circuit. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. An automatic tuning system for a magnetic field generator comprising:
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a processor; a power source; a tuned circuit comprising an adjustable magnetic field generating inductor (L) and an adjustable capacitor (C), the adjusted values of the L and C establishing the tuned circuit resonant frequency, a power amplifier coupled to the power source, said power amplifier having an output coupled to and adapted to drive the tuned circuit; a reference frequency oscillator circuit coupled to the power amplifier so as to cause the power amplifier to generate an output signal at a reference frequency; and a sense circuit coupled to the power amplifier and adapted to sense a signal indicative of the power delivered by the power amplifier to the tuned circuit and provide thereby a power level signal relating to such power delivered, whereby the power delivered by the power amplifier is a function of the resonant frequency of the tuned circuit, and wherein the processor monitors the power level signal and causes the adjustable capacitor and the adjustable inductor to be adjusted to respective capacitance and inductance values that maximizes the power delivered by the power amplifier. - View Dependent Claims (46, 47, 48, 49)
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50. An automatic tuning system for a magnetic field generator comprising:
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tuned circuit means comprising inductor means and capacitor means, the values of the inductor means and capacitor means establishing the resonant frequency of the tuned circuit means, power means for delivering power to the tuned circuit means at a reference frequency; and means for adjusting the resonant frequency of the tuned circuit means for maximizing the power transferred from the power means to the tuned circuit means, whereby the power delivered by the power means is a function of the resonant frequency of the tuned circuit, wherein the delivered power is maximized when the resonant frequency of the tuned circuit means equals the reference frequency. - View Dependent Claims (51, 52, 53, 54, 55)
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56. In an automatic tuning system for a magnetic field generator comprising, a tuned circuit comprising a magnetic field generating inductor (L) and an adjustable capacitor (C), the values of the L and C establishing the tuned circuit resonant frequency, a power amplifier having an output coupled to and adapted to drive the tuned circuit, the power amplifier providing, at said output, a tuned circuit drive signal at a preselected reference frequency, a method of tuning the tuned circuit comprising the steps of:
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(1) commencing the tuning of the tuned circuit with the adjustable capacitor at an initial capacitance value; (2) measuring the power delivered by the power amplifier to the tuned circuit; (3) changing the capacitance value of the adjustable capacitor; (4) repeating steps 2 and 3 through a range of capacitance values of the adjustable capacitor; and (5) adjusting the adjustable capacitor to have the capacitance value that provided the maximum value of the delivered power measured in step (2).
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57. An automatic tuning system for a magnetic field generator comprising:
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a processor; a power source; a tuned circuit comprising a magnetic field generating inductor (L) and an adjustable capacitor (C), the values of the L and C establishing the resonant frequency of the tuned circuit; a power amplifier coupled to the power source, said power amplifier having an output coupled to and adapted to drive the tuned circuit; a reference frequency oscillator circuit providing a reference frequency signal, said oscillator circuit coupled to the power amplifier so as to cause the power amplifier to generate an output signal at the reference frequency; and a sense circuit coupled to the reference frequency oscillator circuit and adapted to sense a first parameter related to the reference frequency signal, the sense circuit further coupled to the inductor and adapted to sense a second parameter related to the inductor and provide an error signal as a function of the first and second parameters, wherein the power delivered by the power amplifier to the tuned circuit is a function of the resonant frequency of the tuned circuit, and wherein the processor monitors the error signal and causes the adjustable capacitor to be adjusted to a capacitance value that optimizes the error signal to thereby optimize the power delivered by the power amplifier. - View Dependent Claims (58, 59, 60, 61)
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Specification