To provide a function for automatically measuring and storing of a position compensation value to obtain a d-axis position from the output of a position detector, in order to eliminate the problem of how to eliminate the manual procedures for measurement and procedures to attain no-load condition.

This controller is provided with a measurement storage device, comprising a d-axis estimator for estimating the d-axis position by allowing the predetermined current to flow, a position compensating value calculator for calculating a position compensated value and a compensated value storage for storing a position compensated value.