Patent attributes
A motor control device that controls a permanent-magnet synchronous motor has: a magnetic flux controller that derives, as a specified excitation current value, a specified current value corresponding to a d-axis component of a current passing through an armature winding; and a current controller that controls, based on the specified excitation current value, the current passing through the armature winding. The magnetic flux controller makes the specified excitation current value vary periodically, based on an estimated or detected rotor position, in a current range in which the magnetic flux produced by the permanent magnet is weakened, and changes the specified excitation current value according to a rotation speed of the rotor.