Ultrasonic frequency power supply
First Claim
1. An ultrasonic frequency power supply for driving transducer means providing ultrasonic energy to a cleaning liquid, comprising:
- means for receiving alternating current input and providing substantially unfiltered full wave rectified direct current output, the undulations of the direct current voltage output having substantially the same phase and amplitude as the voltage of said alternating current input;
inverter means coupled for receiving said direct current output and producing responsive to power control means acting upon said inverter means and series connected impedance matching means an alternating current voltage for driving said transducer means;
said power control means operating said inverter means responsive to;
(a) power measuring means and power adjustable means connected to said control means for causing said transducer means to operate at a set average power level;
(b) phase detection means and frequency control means connected to said control means for causing said transducer means to operate substantially at its resonant frequency; and
(c) power modulation means connected to said control means for optionally providing to said transducer means peak power pulses of a set amplitude but at constant said set average power level.
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Accused Products
Abstract
An ultrasonic power supply for driving piezoelectric transducers in an ultrasonic cleaning apparatus comprises a full-wave rectifier for providing unfiltered direct current to an inverter circuit of the clamped mode resonant converter type, which provides alternating current output at the series resonant frequency condition of the transducers. The inverter circuit switching cycle is controlled responsive to means for causing a set average power level to be maintained, means for causing the resonant frequency to be maintained and including means for causing the resonant frequency to be swept symmetrically by an adjustable sweep frequency. Also, power modulation means are provided for optionally providing to the transducers power bursts of a set amplitude, but at the set average power level. As a result of the unfiltered direct current from the full-wave rectifier, the power supply will operate substantially at unity power factor.
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Citations
9 Claims
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1. An ultrasonic frequency power supply for driving transducer means providing ultrasonic energy to a cleaning liquid, comprising:
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means for receiving alternating current input and providing substantially unfiltered full wave rectified direct current output, the undulations of the direct current voltage output having substantially the same phase and amplitude as the voltage of said alternating current input; inverter means coupled for receiving said direct current output and producing responsive to power control means acting upon said inverter means and series connected impedance matching means an alternating current voltage for driving said transducer means; said power control means operating said inverter means responsive to; (a) power measuring means and power adjustable means connected to said control means for causing said transducer means to operate at a set average power level; (b) phase detection means and frequency control means connected to said control means for causing said transducer means to operate substantially at its resonant frequency; and (c) power modulation means connected to said control means for optionally providing to said transducer means peak power pulses of a set amplitude but at constant said set average power level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An ultrasonic frequency power supply for driving transducer means at its series resonant frequency and said transducer means adapted to provide ultrasonic energy to a cleaning liquid comprising:
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rectifier means for receiving alternating current input and providing a substantially unfiltered direct current voltage having undulations whose amplitude and phrase are substantially coincident with the alternating current input voltage; inverter means having switching means coupled for receiving said direct current voltage and producing, responsive to power control means acting upon said switching means, a direct current voltage, the value of which is commensurate with pulse width modulation effective upon said switching means by said power control means; impedance matching means coupled in series with said inverter means for receiving said direct current voltage from said inverter means and causing filtered alternating current voltage for energizing said transducer means; frequency control means and phase detection means coupled to said power control means for receiving a signal responsive to the phase difference between the alternating voltage and current energizing said transducer means and controlling said inverter means responsive to said phase difference signal for minimizing said phase signal indicating said resonance frequency condition; means coupled for causing said resonant frequency to be swept symmetrically over a set frequency range and at a set rate; further means coupled for measuring the electrical power energizing said transducer means and causing said power control means to control the pulse width modulation of said switching means to provide a substantially constant set average power; power modulator means coupled to said power control means for optionally causing power bursts of a set peak to set average power ratio to be provided to said transducer means; and electrical circuit means coupled in circuit with said power control means for causing the power delivered to said transducer means to be ramped up from a power OFF condition to the set average power.
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Specification