Sliding Mode Variable Structure Control Of Permanent Magnet Toroidal Motor

Permanent magnet toroidal motor is a kind of permanent magnet synchronous motor with planetary worm structure,It has the advantages of large transmission ratio,compact structure,smooth operation,no friction,etc.It realizes the combination of the power device and the reducing mechanism,and simplifies the mechanical and electrical transmission system,which makes it potential applications in the aerospace and other occasions with high requirements for space utilization.In this paper,the inductance of stator and planet gear,the vector control method of motor and the design of sliding mode variable structure controller are deeply studied.Based on the special structure of permanent magnet toroidal motor,the structural characteristics of the permanent magnet toroidal motor are analyzed,a three phase winding coordinate system is established in the right view direction of the worm equivalent pitch circle and the positive view of the central worm and planet wheel.The analytical calculation of the inductance parameters of the permanent toroidal magnet motor is completed,the relationship between the sine and cosine values of the inner spiral angle with Planet frame angle is deduced,the influence of the helix angle and leakage inductance on the inductance equation is analyzed,the inductance equation is Simplified.A mathematical model of permanent magnet toroidal motor is built in three coordinate systems.A permanent magnet toroidal motor vector control system is established,and the tuning method of PI controller is analyzed.A dual closed loop vector control system model of permanent magnetic toroidal motor speed/current is established in Matlab/Simulink.The PI controller and the traditional sliding mode variable structure controller are introduced to get the simulation results.After comparison,it is concluded that the sliding mode controller has smaller system chattering.In view of the problems existing in the PI controller and the traditional sliding mode variable structure controller,a sliding mode variable structure controller based on a new exponential approach rate is designed.The state variables of the system are added to the variable speed of the controller,and the approach speed can be changed with the change of the system state.Compared with the PI controller and the traditional sliding mode controller,the approach speed is speeded up,the system shock is reduced,the chattering of the system is reduced,and the robustness of the system is increased.