Motor drive apparatus and electric power steering apparatus

摘要

The present invention provides a motor drive apparatus capable of calculating an angular velocity and a rotation angle accurately in the entire rotation velocity range of a motor using a cheap Hall sensor having an inferior accuracy without using an expensive resolver having a high accuracy. The present invention includes a first angular velocity calculating means (20) for calculating the angular velocity based on the back-EMF of the motor when it rotates at low speeds and a second angular velocity calculating means (30) for calculating the angular velocity based on a signal from the Hall sensor when it rotates at high speeds. According to the present invention, the angular velocity and rotation angle can be calculated accurately in the entire rotation speed range using the Hall sensor under hybrid usage.