PURPOSE: To provide a simple control circuit for sensorless driving of an AC motor, where a permanent-magnet type synchronous motor and an induction motor are integrated.
CONSTITUTION: An AC variable-speed driving apparatus has an AC motor 100, wherein a permanent-magnet type synchronous motor 20 and an induction motor 30 are made to form a unitary body, inverters 112 and 122, which supply AC powers into the stator windings of the motor 20 and 30, respectively, and a control circuit for these parts. A speed operating circuit 200 operates the rotating speed of the rotor based on the actual values of the voltage and the current or the command values of the voltage and the current of the synchronous motor 20. The rotating speed (n) operated with the speed operating circuit 200 is used as the speed-command value n* for the induction motor 30, and the speed control loop for the induction motor 30 is constituted.
YANASE TAKAO
FUJITA KOETSU
MOTOYOSHI OSAMU
ITO YOSHIO
