PURPOSE: To reduce the deviation of an actual value to the target value of torque by variably controlling magnetizing currents together with torque currents.

CONSTITUTION: A torque target value T is divided by a flux arithmetic value ψ2 from a flux computing element 10 in a divider 1, and changed into the target value iT of torque currents. The target value iT of torque currents is divided by the flux arithmetic value ψ2 in a divider 2, turned into the phase θ1 of a flux vector through a multiplier 3, and integrator 4 and an adder 5, and input to a vector rotating equipment 7. The target value iT of torque currents is input to the vector rotating equipment 7 while being input to a nonlinear function generator 8. The nonlinear function generator 8 generates the original target value of magnetizing currents. A value generated at an output end for a limiter 9 is input to the vector rotating equipment 7 as the actual target value iM of magnetizing currents.