Controller for permanent magnet motor

Abstract

Disclosed is a control device of a permanent magnet electric motor which makes it possible to synchronously control the permanent magnet electric motor even when the magnetic pole logarithm of the permanent magnet electric motor is not an integral multiple of the number of repeats of a rotation phase signal during one rotation. The control device creates a magnetic pole phase signal based on a rotation phase signal, obtained by detecting the rotation of an output axis of the permanent magnet electric motor, and synchronously controls the permanent magnet electric motor in compliance with the magnetic pole phase signal; the control device comprises a first signal conversion unit which converts the rotation phase signal to a rotation angle signal which is proportional to the rotation angle each time a rotor of the permanent magnet electric motor rotates once, and a second signal conversion unit which converts the rotation angle signal to the magnetic pole phase signal, repeated a number of times equal to a magnetic pole logarithm of the permanent magnet electric motor.

Dependencies are inferred from the claim text.