Study On Trajectory Tracking Control Systems Of LPMSM

The linear permanent-magnet synchronous motor(LPMSM) is a typical object with dynamic, time-variable and non-linear character. The main benefits of a LPMSM include the high force density achievable, low thermal losses and most importantly, the high precision and accuracy associated with the simplicity in mechanical structure. Unlike rotary machines, linear motors require no indirect coupling mechanisms as in gear boxes, chains and screws coupling. This greatly reduces the effects of contact-type nonlinearities and disturbances such as backlash and frictional forces, especially when they are used with aerostatic or magnetic bearings. However, the advantages of using mechanical transmission are also consequently lost, such as the inherent ability to reduce the effects of model uncertainties and external disturbances. And a significant and well-known nonlinear effect in the dynamics of the LPMSM is the phenomenon of force ripple arising from the magnetic structure which exhibit characteristics that are position and velocity dependent. Therefore, a reduction of these effects, either through proper physical design or via the control system, is of paramount importance if high-speed and high precision motion control is to be achieved.In this paper the structure and work principle of the LPMSM are analyzed first, based on the mathematics model, the simulink model is built which used the vector control system. A new current compensation method is devoted to overcome the difficulties associated with the nonlinear rippling effects then. The author extend the traditional optimal preview control method, and make it used in any feedback control system. Through the simulink result, the precision effect and respond speed of the new control method can prove it fit for the actual application.