The invention relates to the technical field of
automatic control, and discloses a weak magnetic control method and device for a running speed of an
AC motor. The method comprises the steps of acquiring a direct-axis output
voltage output from a torque inner ring; determining weak magnetic rotational speed compensation according to the direct-axis output
voltage; and adjusting an actual given rotational speed according to the weak magnetic rotational speed compensation, and controlling the rotational speed of the
AC motor according to the adjusted actual given rotational speed. According to the method disclosed by the embodiment of the invention, the weak magnetic rotational speed compensation is determined by acquiring the direct-axis
voltage, the actual given rotational speed after the weak magnetic rotational speed compensation is adjusted according to the weak magnetic rotational speed compensation so as to further control the rotational speed of the
AC motor; and therefore, during deep weak magnetic running of the motor, the rotational speed of the AC motor is controlled according to the actual given rotational speed after the weak magnetic rotational speed compensation, and meanwhile, the working stability of the motor is improved.