Patent ID: 7538700

Claim:
An angular position detector that detects an angular position of a rotor included in a rotary electric device, comprising: a resolver that outputs a signal indicating a rotational angle of the rotor; and a signal processing circuit that calculates the rotational angle of the rotor based on the signal output from the resolver, and outputs the signal indicating the rotational angle, wherein the signal processing circuit includes: sampling device to sample the signal output from the resolver at predetermined intervals, and convert the signal into a digital signal; absolute angle calculation circuit to calculate an instantaneous value of the rotational angle at sampling time, at which the signal output from the resolver is sampled, based on the digital signal; angular speed calculation circuit to calculate an angular speed at the sampling time based on the instantaneous value of the rotational angle; and rotational angle calculation circuit to convert the angular speed into a temporal change in the rotational angle, and for calculating the rotational angle at the sampling time, which accurately matches an actual rotational angle that changes with time.