H_∞ Control For Magnetic Levitation Permanent Magnet Linear Servo System Based On LMI

Magnetic levitation permanent magnet linear motor, which partakes of both permanent magnet motor and linear motor, has many advantages such as no contact, and no friction etc. It has a broad application prospect. 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)". This dissertation researches on the magnetic levitation permanent magnet linear servo driving system. Aiming at the uncertainty disturbance of magnetic levitation permanent magnet linear motor, an H∞robust control design for driving system based on linear matrix inequality (LMI) was proposed in order to make the magnetic levitation permanent magnet linear servo driving system has good robust performance when disturb uncertainly. The main contents are as follow.First, the mechanism of the servo driving system is discussed and a mathematical model is constructed. There are two independent winding with respect to electric on rotor, one can be used to produce magnetic driving, and the other can be used to adjust levitation. For the driving winding, the mathematical model is obtained under rotating d-q reference.Second, for magnetic levitation permanent magnet linear servo driving system, the vector control's method is used for decoupling the nonlinear system to unattached linear current subsystem and speed subsystem. According to the H∞performance and the LMI equivalence, design effort converts into finding solution by LMI method, after that a state feedback H∞controller for magnetic levitation permanent magnet motor system is acquired. To verify the design effective, a simulation model is conducted by Simulink based on MATLAB.Third, applied the vector control theory, the design of the magnetic levitation permanent magnet servo system is proposed in this paper which uses the digital signal processor TMS320F2812 as the control center and utilizes Intelligent Power Module PM25RSH120 of MITSUBISHI as apparatus of the inverter as well as the Space Vector Pulse Width Modulation as the control algorithm. At the same time, current detection circuit with current sensor chip IR2175 and protection circuit is designed. And experiments are conducted.