Patent ID: 8344723

Claim:
A phase difference resolver comprising: an excitation coil for receiving an excitation signal, a detection coil for outputting a detection signal, and a control unit for outputting an estimated real-time angular signal based on a phase difference between an excitation-signal zero cross point of the excitation signal and a detection-signal zero cross point of the detection signal, wherein the control unit is configured to detect angles at each detection-signal zero cross point from the phase difference between the detection signal and the excitation signal, estimate a velocity at an angle at a detection-signal zero cross point based on the angle and an angle at a previous detection-signal zero cross point, calculate an estimated angle at a next detection-signal zero cross point based on the velocity, divide a difference between the estimated angle and the angle by predetermined minimum detection angles, and output the estimated real-time angular signal changing by the minimum detection angles in a range after the angle but before the estimated angle.