Control device for ac rotary machine

A control device for an AC rotary machine, which controls an AC rotary machine in which a rotor is rotated by a rotating magnetic field formed by a multi-phase alternating current flowing through an armature winding of a stator, the control device comprising:

• an inverter that applies a voltage to the armature winding of the AC rotary machine;
• an inverter connection unit that connects the armature winding to the inverter;
• a magnetic field generator that generates an angle detecting magnetic field for detecting a rotation angle of the AC rotary machine by rotating in synchronization with the rotor;
• an angle detector that detects two mutually orthogonal components of the angle detecting magnetic field generated by the magnetic field generator as a sine signal and a cosine signal;
• and
• a control calculation unit that controls a voltage applied to the inverter on the basis of a current command of the AC rotary machine and angle information obtained from the sine signal and the cosine signal,
• wherein the control calculation unit includes an angle correction calculation unit that corrects an error in the angle information caused by a noise magnetic field generated by a multi-phase alternating current flowing through the inverter connection unit by using a correction signal having a phase and an amplitude that are determined in accordance with a current vector of the multi-phase alternating current flowing through the inverter connection unit and a phase correction constant and an amplitude correction constant determined from a relative positional relationship between the inverter connection unit and the angle detector, and
• outputs the corrected error as a corrected electrical angle, and
• the control calculation unit controls the inverter on the basis of the corrected electrical angle.