Control method and control device of permanent-magnet type synchronous motor

摘要

The object of the invention is to inhibit the axial displacement caused by the insufficiency of a control response angular frequency of a frequency arithmetic unit of a synchronous motor and realize high-precision torque control also in acceleration/deceleration. To achieve the object, the axial displacement of the synchronous motor caused by the insufficiency of the control response angular frequency of the frequency arithmetic unit is estimated in consideration of the control response angular frequency and input Deltathetac 3 (=Deltathetac 1 +Deltathetac 2 ) including an estimated value Deltathetac 2 in addition to an axial displacement operated value Deltathetac 1 to the frequency arithmetic unit is acquired. Hereby, even if the frequency arithmetic unit has an insufficient control response angular frequency, the quantity of axial displacement which will be caused by the insufficiency is estimated as a second axial displacement signal Deltathetac 2 , is added and input. Therefore, actual axial displacement Deltathetac 1 of the synchronous motor is stable at a value substantially close to zero.