초록 ▼

A method of controlling current in an AC motor to inhibit small torques on an unloaded motor output shaft and to improve buildup of steady-state operating flux in a rotor includes supplying current to the stator windings through a plurality of semiconductor switches, operating the semiconductor swit

A method of controlling current in an AC motor to inhibit small torques on an unloaded motor output shaft and to improve buildup of steady-state operating flux in a rotor includes supplying current to the stator windings through a plurality of semiconductor switches, operating the semiconductor switches to supply a plurality of gradually increasing currents to the stator windings over a time interval corresponding to approximately one rotor time constant to bring flux in the rotor up to approximately 10% of a steady-state operating flux in the rotor, operating the semiconductor switches to supply a current that is the maximum current rated for pulsed operation of the semiconductor switches for a time interval over which a product of current and time is sufficient to produce steady-state operating flux in the rotor, and then reducing the stator current to a level for maintaining steady-state operating flux in the rotor. A microelectronic apparatus for carrying out the method is also disclosed.

대표청구항 ▼

In a vector control apparatus for controlling flux-producing current and torque-producing current, a method of supplying flux-producing current to windings of a stator in an AC motor to improve buildup of steady-state operating flux in a rotor of the motor, where initially flux is not established in

In a vector control apparatus for controlling flux-producing current and torque-producing current, a method of supplying flux-producing current to windings of a stator in an AC motor to improve buildup of steady-state operating flux in a rotor of the motor, where initially flux is not established in the rotor, the method comprising: supplying current to the windings of the stator through an inverter which includes a plurality of semiconductor switches; commanding flux-producing current to a high level than a level required to maintain steady-state operating flux in the rotor; operating the semiconductor switches in the inverter in response to the commanding of the flux-producing current to supply an initial flux-producing current to the windings of the stator up to the maximum current rated for pulsed operation of the semiconductor switches, wherein the initial current is greater than the steady-state flux-producing current for maintaining normal saturated flux in the rotor; maintaining the initial current for a time interval over which the product of initial current and time is sufficient to produce a steady-state operating flux in the rotor; and after such interval, operating the semiconductor switches in the inverter to reduce current supplied to the windings of the stator to a current for maintaining steady-state operating flux in the rotor.