| 摘要 |
PROBLEM TO BE SOLVED: To make stable operation of a motor without generating excessive current, even when the motor is restarted after it is recovered from instantaneous power interrupt ion. SOLUTION: In a control section 7 of an induction motor, a command section 9, a speed acceleration and deceleration control section 10, a feedback current selection circuit 13, a current angular speed control section 14, switches 16, 17, an output angular speed section 18, a current control and judgement circuit 22, an angular speed phase circuit 37, and a reference angular speed section 38 are installed. The angular speed phase circuit 37 comprises a voltage αβ conversion section 30-2, a voltage dq conversion section 31, a zero command section 32, and a proportional and integral operation section 34. At the instantaneous power interruption, an output angular speed value before the instantaneous power interruption is stored as a reference angular speed and the speed acceleration and deceleration control is stopped, and the angular speed phase control is started, to match the output angular speed of a power inverter to the angular speed and phase of the induced voltage of the motor. When the motor is recovered from the instantaneous power interruption, the decline of the induced voltage of the motor to a specified value or below is confirmed and then the angular speed phase control is stopped and the speed acceleration and deceleration control is restarted from the output angular speed which is synchronous with the motor. |
