Inverter control apparatus
First Claim
1. An inverter control apparatus for controlling a three-phase inverter which operates a three-phase induction motor under a power running condition or a regeneration running condition according to a motor control signal, said inverter control apparatus comprising:
- a current-signal generator for generating a set current signal according to said motor control signal;
a current detector for detecting a real current and for generating a real current signal;
a deviation detector for detecting a deviation between a set-current and said real current based on said set current signal and said real current signal;
first means for providing a three-phase modulation control of said motor in which a modulation percentage of said phase voltage of said inverter is applied to each phase-winding of said motor and for providing a two-phase modulation control of said motor in which a fixed modulation percentage of one phase-voltage of said inverter is applied to one-phase-winding of said motor during a fixed period;
second means for causing said first means to provide said two-phase modulation control if said motor is operating under said power running condition and to provide said three-phase modulation control if said motor is operating under said regenerating running condition; and
a wave-signal generator for controlling said inverter according to an output of said second means and said detected deviation thereby causing a first voltage wave for said two-phase modulation control to be applied to said phase winding of said motor if said two-phase modulation control is performed and causing a second voltage wave for said three-phase modulation control to be applied to said phase windings of said motor if said three-phase modulation control is performed.
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Accused Products
Abstract
In order to reduce distortion of a real-current wave form and to suppress substantial transient fluctuation of the current and torque during changeover from a regeneration running condition to the power running condition of a three-phase induction motor, changeover from the three-phase-modulation control to the two-phase-modulation control is carried at the same time the power running condition of the motor is changed to the regeneration running condition according to the motor-state-quantum such as a detected slip ratio, detected torque, detected current or the like. Thus, distortion of the motor-current wave form is reduced and significant fluctuation of the motor-current and torque during the changeover is reduced.
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Citations
10 Claims
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1. An inverter control apparatus for controlling a three-phase inverter which operates a three-phase induction motor under a power running condition or a regeneration running condition according to a motor control signal, said inverter control apparatus comprising:
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a current-signal generator for generating a set current signal according to said motor control signal; a current detector for detecting a real current and for generating a real current signal; a deviation detector for detecting a deviation between a set-current and said real current based on said set current signal and said real current signal; first means for providing a three-phase modulation control of said motor in which a modulation percentage of said phase voltage of said inverter is applied to each phase-winding of said motor and for providing a two-phase modulation control of said motor in which a fixed modulation percentage of one phase-voltage of said inverter is applied to one-phase-winding of said motor during a fixed period; second means for causing said first means to provide said two-phase modulation control if said motor is operating under said power running condition and to provide said three-phase modulation control if said motor is operating under said regenerating running condition; and a wave-signal generator for controlling said inverter according to an output of said second means and said detected deviation thereby causing a first voltage wave for said two-phase modulation control to be applied to said phase winding of said motor if said two-phase modulation control is performed and causing a second voltage wave for said three-phase modulation control to be applied to said phase windings of said motor if said three-phase modulation control is performed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification