Patent ID: 7336456

Claim:
A control-motor system, the system for driving a 2m-pole motor based on a rotor rotation angle θ detected by a 2n-pole resolver, where m and n being counting numbers, the system comprising: the sum of the square of a signal modulated by sin θ and the square of a signal modulated by cos θ in the resolver in which an excitation signal generated in said system is modulated by sin θ and cos θ in response to the rotor rotation angle θ of the resolver is compared to a predetermined malfunction threshold value, so that malfunction determination related to the resolver is performed, and also, given that the sum is a 2 when the resolver is recognized to be in normal operation, the malfunction determination threshold value is made to be not smaller than {a×cos((π/2)/(m/n))} 2 .