Patent ID: 8134317

Claim:
A motor controller for controlling a permanent magnet motor including a rotor provided with a permanent magnet and a stator provided with multiphase windings, comprising: a position detector that generates and outputs a rotational position signal of the rotor; a waveform data storage that stores sinusoidal waveform data; a drive signal output section that reads the waveform data from the waveform data storage at timings determined based on the rotational position signal and that outputs a voltage signal corresponding to the waveform data to the windings through a drive section; a data history storage that stores data corresponding to the voltage signal outputted in a previous control period; and an output data modifier that, when outputting the voltage signal in a current control period, compares corresponding waveform data with a previous data stored in the data history storage, and if difference between the current waveform data and the previous data is equal to or greater than a predetermined value, data to be currently outputted is modified by an amount corresponding to a portion of the difference.