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1. (WO1984002235) AC MOTOR CONTROL SYSTEM

Pub. No.:    WO/1984/002235    International Application No.:    PCT/JP1983/000421
Publication Date: Jun 7, 1984 International Filing Date: Nov 25, 1983
IPC: H02P 23/00
H02P 25/02
Applicants:
Inventors:
Title: AC MOTOR CONTROL SYSTEM
Abstract:
An AC motor control system comprises: a detector (113) for detecting the angular velocity of an AC motor (101); a detector (112) for detecting the actual current flowing through the AC motor (101); a power drive circuit for driving the AC motor (101); and a control unit (108) which carries out a velocity loop calculation to obtain a current command from the differential velocity between the velocity command of the AC motor (101) and the actual detected velocity, and a current loop calculation to obtain a differential current between the obtained current command and the actual detected current. In the current loop calculation in the control unit (108), a velocity-compensating signal is obtained by amplifying the actual detected velocity by a predetermined amplification factor to compensate for the command to the power drive circuit. The current loop calculation is executed during a sampling period smaller than that of the velocity loop calculation. In the velocity loop calculation, the actual current during a sampling period is estimated from the current command value in the sampling period immediately beforehand, and the current command is calculated from the actual estimated current and the differential velocity.