Patent ID: 7332888
Filing Date: 2008-02-19
Classification: H02P

Abstract:
1. A motor driving apparatus, which drives an induction motor, comprising: a current instruction calculator, for calculating a current instruction value based on a deviation between a speed instruction value and an estimated speed value; a current controller, for controlling an output current based on the current instruction value; a frequency instruction calculator, for calculating a frequency instruction value based on an output voltage instruction value or on an output voltage detection value; wherein, when the induction motor is to be activated, the current instruction value and the frequency instruction value are calculated using the speed instruction value, and an output current and an output frequency are controlled in accordance with the current instruction value and the frequency instruction value; wherein the current instruction calculator includes: a speed controller, for receiving a difference between a speed instruction value and an estimated speed value and outputting a first torque instruction; a speed control output correction unit, for, when the induction motor is to be activated, reducing the first torque instruction output by the speed controller; and a torque calculation instruction unit, for receiving the speed instruction value and outputting a second torque instruction value; and wherein, when the induction motor is to be activated, the magnitude of the first torque instruction value is reduced, and a current instruction value is calculated based on the second torque instruction value.