Patent ID: 8288977

Claim:
A rotation angle calculation apparatus calculating by means of a multipole resolver a rotation angle of a motor included in a drive apparatus having said motor and an inverter for controlling said motor, a mechanical period taken for said motor to make one full rotation including the number, which is corresponding to the number of poles of said resolver, of resolver periods each taken for a detected angle of said resolver to complete one cycle, said rotation angle calculation apparatus comprising: a calculation unit calculating an error of the detected angle of said resolver for each said resolver period; and a correction unit calculating a corrected value of said detected angle detected by said resolver by correcting said detected angle using said error calculated before said detected angle is detected, and said correction unit performing a transition correction in such a manner that a first extent to which a first error in a resolver period later than a resolver period of one mechanical period ago is reflected on said corrected value is larger when said drive apparatus is in a transition state than the first extent when said drive apparatus is not in the transition state.