The invention relates to a jiggling phase searching method, wherein a phase searching current is applied to the winding of the three-phase AC
servo motor, and an electric
angle alpha of the rotor magnetic pole relative to the
stator is determined through measuring jiggling of the motor, which includes steps: 1. defining and initializing the phase searching parameters; 2. applying a gradually increased phase searching current corresponding to the assumed value of the electric
angle alpha[0] so as to generate jiggling of the rotor, then turning to the step 5 if the phase searching current reaches a maximum value I[max] and the movement of the rotor still does not exceed a permitted deviation angle
delta; 3. determining an angle modification value theta; 4. modifying the assumed value of the electric
angle alpha[0] based on jiggling direction of the
servo motor and the angle modification value theta, then returning to the step 2; 5. using the assumed value of the electric angle alpha' as the actual value of the electric angle alpha; and optionally 6. determining and correcting the phase sequence of the three-phase winding wiring of the motor, wherein the angle modification value can be determined by subsequently using a
bisection method and a bias weighted stepping method. Comparing with methods in prior art, the method has features of small
stroke, fast phase searching speed, high phase searching precision, and wide range of compatibility because it is applicable not only to the rotation motors, but also to the linear motors.