Motor controller and vehicular steering system using said motor controller

摘要

A low speed region position estimating portion 41 is designed to be suitable for when the motor is operating in a low speed region, and estimates a low speed estimated rotational position ¸^ L . A high speed region position estimating portion 42 is designed to be suitable for when the motor is operating in a high speed region, and estimates a high speed estimated rotational position ¸^ H . A dividing portion 43 obtains a divided estimated rotational position ¸^ M by internally dividing the low speed estimated rotational position ¸^ L and the high speed estimated rotational position ¸^ H . A rotation speed calculating portion 24 obtains a rotation speed É of a rotor based on an output signal from a steering sensor 4. The rotational position of the rotor is then obtained by selecting one of i) the low speed estimated rotational position ¸^ L , the high speed estimated rotational position ¸^ H , or the divided estimated rotational position ¸^ M , based on that rotation speed É.