Apparatus for controlling an A-C powered elevator
First Claim
1. An apparatus for controlling an A-C powered induction motor for an elevator cage, said apparatus comprising:
- a rectifier for converting 3-phase A-C power into D-C electric power,an inverter connected to said rectifier for converting the D-C power into A-C power of variable voltage and variable frequency,a current detector connected to detect input current of said inverter,a power means for detecting power supplied to said inverter based upon an output of said current detector,control means for generating a command signal to control said inverter in accordance with slip of the induction motor as determined by the power supplied to the inverter, andcorrecting means operable responsive to the power detected by said power detector means for operating said inverter to correct the slip of said motor to maintain the power supplied to the inverter at predetermined values.
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Accused Products
Abstract
An apparatus for controlling an A-C powered induction motor for an elevator cage, said apparatus comprising a rectifier for converting 3-phase A-C power into D-C electric power, an inverter connected to the rectifier for converting the D-C power into A-C power of variable voltage and variable frequency, a current detector connected to detect input current of the inverter, a power detector for detecting power supplied to the inverter based upon an output of the current detector, a control unit for generating a command signal to control the inverter in accordance with slip of the induction motor as determined by the power supplied to the inverter, and a correcting unit operable responsive to the power detected by the power detector for correcting the slip of the motor to maintain the power supplied to the inverter at predetermined values.
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Citations
11 Claims
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1. An apparatus for controlling an A-C powered induction motor for an elevator cage, said apparatus comprising:
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a rectifier for converting 3-phase A-C power into D-C electric power, an inverter connected to said rectifier for converting the D-C power into A-C power of variable voltage and variable frequency, a current detector connected to detect input current of said inverter, a power means for detecting power supplied to said inverter based upon an output of said current detector, control means for generating a command signal to control said inverter in accordance with slip of the induction motor as determined by the power supplied to the inverter, and correcting means operable responsive to the power detected by said power detector means for operating said inverter to correct the slip of said motor to maintain the power supplied to the inverter at predetermined values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for controlling an A-C powered induction motor for an elevator cage, said apparatus comprising:
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a rectifier for converting 3-phase A-C powered into D-C electric power, an inverter connected to said rectifier for converting the D-C power into A-C power of variable voltage and variable frequency, a current transformer for detecting current of said motor and for generating a motor current signal, current command generating means for generating a current command signal for the inverter, a voltage command generator for generating a voltage command signal for the inverter from a deviation between the current command signal and the motor current signal, a phase detector means for detecting phase of the voltage command signal so as to determine slip of the induction motor represented by power supplied to said inverter, and slip correcting means for correcting the slip of the induction motor to maintain the power supplied to the inverter at predetermined values and for supplying the corrected slip from the output of said phase detector means to said current command generator means. - View Dependent Claims (10, 11)
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Specification