A motor control method comprises detecting operating parameters of a motor system comprising a plurality of windings, a rotor, a stator magnetically coupled to the rotor and a plurality of power converters connected to the plurality of windings, determining, by a controller, a suitable pole number and a preliminary set of operating variables based upon the operating parameters, reducing operating stresses of the motor system gradually and after reducing the operating stresses, configuring the plurality of power converters so as to adjust the number of poles of the motor system according to the suitable pole number.