DRIVING DEVICE, DRIVING SYSTEM, AND DRIVING METHOD FOR PERMANENT MAGNET SYNCHRONOUS MOTOR

When controlling the driving of a permanent magnet synchronous motor, in order to estimate magnet's magnetic flux with high accuracy and robustness against harmonic components of induced voltage and errors in setting constants for resistance and inductance without using a voltage sensor, a speed sensor, and data from magnetic field analysis or experiments, this driving device for a permanent magnet synchronous motor has capability of improving torque accuracy by estimating the amount of magnetic flux or the temperature of the magnet in the permanent magnet synchronous motor on the basis of a voltage command value and speed information about the permanent magnet synchronous motor, in a state in which a current command value when the torque command value is zero is being output, so as to estimate the magnet's magnetic flux or the temperature with high accuracy and robustness against harmonic components of induced voltage and errors in setting constants for resistance and an inductance without using the data from magnetic field analysis or experiments.