In order to improve speed loop control performance of permanent magnet synchronous motor（PMSM）

chattering problem is further difficult to eliminate on the basis of integral sliding mode

and stability of speed control and load resistance are improved.The extended state observer is used to expand the load and its interference into a state variable

and the expansion state is compensated to the control quantity

thereby improving the static characteristics of the system.At the same time

the proportional state variable is introduced into the integral state variable link to accelerate the reaction time of the integral sliding mode and improve the dynamic characteristics of the control system.Finally

the simulation experiment and the traditional PI control are used to compare the system simulation load resistance

and the speed stability experiment is compared.The results show that the dynamic and static performance of the system is improved compared to the traditional control method.