Patent ID: 7928675

Claim:
A feedback control method for detecting phase currents of three or more phases on fixed coordinates of a polyphase electric motor with current sensors so as to be transformed into detection currents on rotating coordinates by fixed/rotating coordinate transformation and controlling the currents supplied to respective phases of the polyphase electric motor based on the detection currents on the rotating coordinates and target currents on the rotating coordinates, the feedback control method comprising: performing digital conversion of odd-phase current detection signals that are output from the current sensors into phase current data sequentially at a time interval; and on a basis of a reference time point of digital conversion at a center of a sequence of the digital conversion, correcting a pole position of the phase current data whose digital conversion leads ahead of the reference time point into a value that is increased by the lead, correcting the pole position of the phase current data whose digital conversion lags behind the reference time point into a value that is reduced by the lag, and using corrected values for the fixed/rotating coordinate transformation.