Terminal Sliding Mode Control of PMSM Based on Extended State Observer

In order to weaken the chattering of the sliding mode control and improve the convergence speed of the approaching motion phase and the sliding mode motion phase.Introducing the inverse tangent function of the absolute value of the state variable and the hyperbolic sine function of the switching function to design a new reaching law,combined with non-singular fast terminal sliding mode to design control law.In order to reduce the effects of viscosity coefficient and load torque disturbance,and improve the robustness of the permanent magnet synchronous motor control system.Observing the disturbance with a second-order extended state observer,the observations are introduced into the sliding mode speed controller for feedforward compensation.The nonlinear function adopts hyperbolic sine function to avoid the observer parameter being too large.The simulation result shows that second-order extended state observer is ability to quickly and accurately track disturbances.Compared to PI control,sliding mode control with feedforward compensation, no overshoot, faster response and stronger robustness.