Research On Fractional Sliding Mode Control Of PMSM Speed Control System

Against the background of the rapid development of modern control methods,permanent magnetic materials and power electronics technology,based on the advantages of high efficiency,simple structure and small volume,PMSM（permanent magnet synchronous motor）,which has been widely used in many industries such as petroleum,rubber,textile,etc..The speed regulation of permanent magnet synchronous motor（PMSM）has been the focus of attention and research.In this paper,the structure of synchronous motor and its mathematical model、basic working principle are introduced at first,and then the coordinate transformation theory,which is often used in the control of synchronous motor,is introduced,the basic idea of the traditional permanent magnet synchronous motor（PMSM）speed control and the realization method are described in detail.Then,the control mode of permanent magnet synchronous motor is discussed in this paper,finally,the vector control strategy with i_d^*=0 is selected.In the field of motor control,PI controller is widely used.With the deepening of application,PI controller can not meet the requirements of modern control.Sliding mode variable structure control has strong anti-interference performance,simple control principle,small amount of calculation and easy program design,but it will also produce chattering which is difficult to eliminate.Based on this,the fractional-order differential and integral theory is introduced into the sliding mode control.The fast power sliding mode approach rate and sliding surface are improved by using the characteristics of the slow energy transfer of fractional calculus,and a speed regulating system based on the fractional-order sliding mode controller is designed,the effectiveness of the algorithm is verified by simulation.Then the fractional-order sliding mode control scheme is compared with the traditional PI and sliding mode Control Scheme,and the results show that the fractional-order sliding mode control has better performance,which improves the dynamic performance of the system and weakens the chattering.Finally,the speed control system platform of PMSM is built,and the hardware circuit and software circuit are designed respectively.Based on the platform,the sliding mode variable structure control strategy proposed in this paper is further verified.The experimental results show that the proposed control scheme is effective.