Synchronous motor and a rotation control method thereof, as well as, an inverter for use of the synchronous motor

Abstract

A rotation control method of a synchronous motor, the motor comprising: a stator having AC windings thereround; and a rotor, being mounted within said stator, rotatably, wherein on an each surface, opposing to the rotor, of poles building up the stator, are formed plural numbers of teeth portions, and on a surface of the rotor, being made of permanent magnet, opposing to the poles of the stator, are also formed plural numbers of teeth portions, with a width being nearly equal to that of the teeth portion in a circumference direction thereof, and further AC voltages having a predetermined voltage-frequency characteristic is supplied to AC windings wound around the poles of the stator, and the AC voltages supplied from the inverter is so determined in the voltage-frequency characteristic thereof, at least within a part of frequency band equal or less than a predetermined rated frequency, a pull-out torque of the synchronous motor is equal to or greater that a rated pull-out torque at the predetermined rated frequency, thereby providing a synchronous motor and also an inverter to be used for such the synchronous motor, but hardly causing the step-out phenomenon in the operating condition when accelerating and decelerating the synchronous motor.