Patent ID: 9571019
Date: 2017-02-14
CPC Classifications: H02P

Claim:
1. A control device of a motor that rotates a rotor by a magnetic flux generated by supplying an excitation current to a coil, the control device of a motor comprising: a detection section that detects a value of a counter-electromotive voltage induced in the coil by rotation of the rotor; a normalizing section that normalizes the value of the counter-electromotive voltage by using a normalization coefficient according to a speed of rotation of the rotor; and a specifying section that specifies a position of the rotor based on the value of the counter-electromotive voltage that is normalized, wherein a value of the normalization coefficient is decreased with an increase in the speed when the speed is equal to or greater than a predetermined value and is a constant value when the speed is less than the predetermined value.