Method for self-adjusting control parameters of speed ring of permanent magnet synchronous motor based on fractional orders

The invention discloses a method for self-adjusting control parameters of a speed ring of a permanent magnet synchronous motor based on fractional orders. An integer-order proportional integral (PI) controller in an alternating current servo system of the permanent magnet synchronous motor is replaced by a fractional-order PI controller, parameters of the fractional-order PI controller are automatically adjusted, and the alternating current servo system of the permanent magnet synchronous motor can be controlled. The method specifically comprises the following steps of: firstly, acquiring current and speed signals of the alternating current servo system; secondly, identifying a speed ring controlled object model of a permanent magnet synchronous motor servo system according to the acquired signals, and identifying the parameters of the model; and finally, optimally adjusting the control parameters, and thus obtaining optimal control parameters. According to the method, the original integer-order PI controller is replaced by the fractional-order PI controller, and the parameters of the controller are automatically adjusted; the parameters of the controller are optimized by using a pattern search algorithm; and the adjusted parameters of the controller are high in robust, high in anti-disturbance capacity and high in control accuracy.