SENSORLESS CONTROL DEVICE FOR SYNCHRONOUS ELECTRIC MOTOR

摘要

A synchronous electric motor sensorless control device for driving a synchronous electric motor without using any rotational position measuring device. The sensorless control device comprises a relative position counter 4 for resetting an accumulated value to zero when a reference position signal serving as a reference for a positioning count is inputted and fetching a magnetic pole position estimate as a reference position from the position/speed estimator to start the accumulation, and a speed command generator 3 having a position controller 29 for controlling the position by the difference between the command value of the displacement from the reference position and the accumulated value outputted as a relative position from the relative position counter, and adapted for outputting a speed command. Thus, the sensorless control device can place the synchronous electric motor having no position sensor in a predetermined position.