Permanent Magnet Linear Motor Magnetic Levitation System Robust Control Strategy Research

The dissertation is based on high precision high speed CNC machine tools application as a background, and research on magnetic levitation permanent magnet linear synchronous motor and the magnetic levitation subsystem of the motor under the help 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". The main research contents are as follows:(1)Rsearch on operation mechanism of magnetic levitation permanent magnet linear synchronous motor. Mathematical models of electromagnetic force, voltage equation, flux equation, dynamic equation are derived based on the operating principle and vector control theory of magnetic levitation permanent magnet linear synchronous motor when a special control strategy iq=0 is used on the magnetic levitation-winding. Further more, the correctness and effectiveness of magnetic levitation force mathematical model is confirmed.(2) H∞robust controller of magnetic levitation subsystem of the magnetic levitation permanent magnet linear synchronous motor is designed. On the basis of nonlinear mathematical model of the motor, derive the nonlinear system state feedback linearization control law with the input/output feedback linearization method. And the magnetic levitation subsystem linear state space model is obtained through the coordinate transformation. The magnetic levitation subsystem control problem convert as a standard H∞control problem, and the H∞robust controller which inhibition of the uncertain external disturbances is got from a positive definite solution by solving the Riccati inequality. Finally, Matlab/Simulink is used for simulation research for the magnetic levitation subsystem.(3)Hardware design and software design of the magnetic levitation digital control system. The main circuit of the control system adopts IPM module PM50RSA120 as the core of voltage source type inverter. The control circuit is mainly composed by TMS320F2812. The software includes a main program, timer underflow interrupt service subprogram and capture interruption service subprogram.(4)Experimental research for the magnetic levitation permanent magnet linear synchronous motor. On the purpose of research the prototype performance, magnetic levitation-winding no-load back electromotive force of the magnetic levitation permanent magnet linear synchronous motor is measured and the harmonic of it is analyzed. At the same time, finite element calculation results are compared with it. Finally, the experimental research is done for eddy current sensor input and output performance which is used for measuring magnetic levitation height.