The Research Of Nonlinear Control In AC Permanent Magnet Synchronous Motor

Permanent Magnet Synchronous Motor(PMSM)has some advantages with small size,high efficiency,high power factor,low inertia,high-speed response and easy control,etc.So it is widely used in CNC,robot and electric vehicles and other high accuracy requirement industry.Focusing on the modeling,system analysis and design of advanced control algorithms,the closed-loop performance in AC PMSM servo system will be researched.First of all,this article describes the current status of research and analysis of PMSM control and introduces the vector control method in AC servo system.Then based on this,for improving the anti-interference ability of closed-loop system,it researches the disadvantages of the traditional PID AC servo system.Next it designs an AC servo system method based on nonlinear sliding mode control.In the three closed-loop PMSM control system,it builds a third-order equation with the motor position and desired q-axis the stator current,also discusses the design of sliding mode control algorithm and the stability analysis.Meanwhile it makes simulation and gets the result of sliding mode control's chattering,chattering cause and reducing method.Researching the improvement solution based on saturation function in sliding control system,it can weaken chattering range.Based on these,it raises a new improved saturation function accompanying with simulation studies,and it is verified to get a nice improvement in chattering but also have a better robustness with system load disturbances and parameter variations.