Power control system for an A.C. induction motor
First Claim
1. A power control system for an A.C. induction motor, comprising:
- a voltage/current phase difference generator for determining a difference in phase between a voltage applied to the motor and a current drawn by the motor, and for generating a phase difference signal as a function of the determined difference in phase; and
an integrator, the integrator receiving the phase difference signal and generating an error signal for controlling an amount of power supplied to the motor as a function of the phase difference signal;
the integrator including a feedback filter having first and second feedback paths, the first feedback path including a first polarized capacitor, the second feedback path including a second polarized capacitor and a resistor.
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Accused Products
Abstract
A power factor control system for an A.C. induction motor determines the difference in phase between the voltage applied to the motor and the current drawn by the motor. Based upon this difference in phase, an integrator generates an error signal. The error signal is compared with a ramp wave to derive a pulse signal which controls the voltage applied to the motor, which in turn controls the amount of current supplied to the motor, in order to reduce the power consumed by the motor. The integrator includes a dual-path feedback filter having a polarized capacitor in each path. A power supply is used to quickly provide the full operating bias voltages required by several of the components contained in the control system.
46 Citations
18 Claims
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1. A power control system for an A.C. induction motor, comprising:
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a voltage/current phase difference generator for determining a difference in phase between a voltage applied to the motor and a current drawn by the motor, and for generating a phase difference signal as a function of the determined difference in phase; and an integrator, the integrator receiving the phase difference signal and generating an error signal for controlling an amount of power supplied to the motor as a function of the phase difference signal; the integrator including a feedback filter having first and second feedback paths, the first feedback path including a first polarized capacitor, the second feedback path including a second polarized capacitor and a resistor. - View Dependent Claims (2, 3, 4, 5)
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6. A power control system for an A.C. induction motor, comprising:
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a voltage/current phase difference generator for determining a difference in phase between a voltage applied to the motor and a current drawn by the motor, and for generating a phase difference signal as a function of the determined difference in phase; means for controlling an amount of power supplied to the motor as a function of the phase difference signal; an electrical power supply, including; a current-limiting component; a discharge capacitor coupled to the current-limiting component; a rectifier coupled to the discharge capacitor; and a filter capacitor coupled to the rectifier; the rectifier is a full-wave rectifier including a first and second diode; a terminal of the discharge capacitor is coupled to each of an anode of the first diode and a cathode of the second diode; a positive terminal of the filter capacitor is coupled to a cathode of the first diode; and a negative terminal of the filter capacitor is coupled to an anode of the second diode.
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7. A power control system for an A.C. induction motor, comprising:
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means for determining a difference in phase between a voltage applied to the motor and a current drawn by the motor, and for generating a phase difference signal as a function of the determined difference in phase; an integrator, the integrator receiving the phase difference signal and generating an error signal for controlling an amount of power supplied to the motor as a function of the phase difference signal; the integrator including a feedback filter having first and second feedback paths, the first feedback path including a first polarized capacitor, the second feedback path including a second polarized capacitor and a resistor; and an electrical power supply, including; a current-limiting component; a discharge capacitor coupled to the current-limiting component; a rectifier coupled to the discharge capacitor; and a filter capacitor coupled to the rectifier. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A power controller for an A.C. induction motor, comprising:
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a voltage/current phase difference generator for generating a phase difference signal indicative of a difference in phase between a voltage applied to the motor and a current drawn by the motor; and an integrator coupled to the voltage/current phase difference generator for controlling an amount of power consumed by the motor as a function of the phase difference signal, the integrator including a feedback filter having at least one polarized capacitor. - View Dependent Claims (15, 16)
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17. A method of controlling an amount of power supplied to an A.C. induction motor, comprising the steps of:
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determining a difference in phase between a voltage applied to the motor and a current drawn by the motor; generating a phase difference signal as a function of the determined difference in phase; generating a control signal from an integrator receiving the phase difference signal for controlling an amount of power supplied to the motor as a function of the phase difference signal; providing a first feedback through a first polarized capacitor of the integrator; and providing a second feedback through a second polarized capacitor and a resistor of the integrator. - View Dependent Claims (18)
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Specification