Research On Direct Magnetic Levitation Permanent Magnet Linear Motor Feeding System Of Cnc Machine Tools

Research on direct magnetic levitation permanent magnet linear motor feeding system of CNC machine tools is a comprehensive project, which is on the basis of modern servo theory, the direct magnetic levitation permanent magnet linear motor as the object of study, CNC machine tools as the background of application. To eradicate the friction of feeding system in CNC machine tools is the research purpose. This dissertation has project background of the National Natural Science Foundation which is titled "Study on the direct magnetic levitation permanent magnet linear motor of CNC machine tools and its servo control system (No.50975181)". From the application status quo of linear servo system and the structural features of various new linear motor, this dissertation studies the direct magnetic levitation permanent magnet linear motor and its feeding system combined with the magnetic levitation theory. The main contents are as follows:1. Study on the working principle of direct magnetic levitation permanent magnet linear motor. The mover consists of two sets of windings. One is used to generate electromagnetic thrust, the other is used to generate magnetic levitation force. And two current control strategies of id=0 and iq=0 are respectively used in thrust winding and levitation winding to realize friction-free feed on the basis of stable levitation.2. Deduce the mathematical model of direct magnetic levitation permanent magnet linear motor. On the basis of magnetic hierarchical model of direct magnetic levitation permanent magnet linear motor, starting from the magnetic field energy, the expression of electromagnetic force is derived through the virtual displacement method. 3. The direct magnetic levitation permanent magnet linear motor is analyzed with FEA. Through the static magnetic field analysis, the rationality of motor structure is investigated; through transient field analysis, the adding and subtracting magnetism effect of levitation windings is mainly studied when the motor is operating stably.4. Study on the feeding system field-circuit coupled simulation of direct magnetic levitation permanent magnet linear motor. In order to achieve the co-simulation of motor feeding process with stable suspension of motor, the main circuit and control circuit model is built by Simplorer, and the finite element model of motor is established by Maxwell software.