Research On Power Magnetic Bearing Levitation Control System Based On DSP

Power Magnetic Bearing combines rotation driving and radial suspension in a whole, it has many advantages that mechanical bearing and magnetic bearing can't compare, and has open up a new research approach for rotating machinery developing. Power Magnetic Bearing mainly includes Permanent-magnet Synchronous type, induction-type, reluctance-type and so on. The paper is mainly studying on suspension mechanism and control method for induction Power Magnetic Bearing.(1) Based on domestic and overseas developing status and research progress of Power Magnetic Bearing, also according to its suspension principle, the mathematical model of radical suspension force containing rotor eccentricity is built.(2) According to strong coupling characteristic of Power Magnetic Bearing, the coupling relationship between torque subsystem and suspension subsystem is analyzed. Basing on decoupling method of U-I model, the suspension decoupling algorism formula is deduced and the independent control algorism of suspension winding is built. Simulation and experiment result verify the validity of the algorism.(3) Digital control system adopting DSP (TMS320LF2407A) as core is designed, containing rotor displacement detecting system, suspension winding current detecting, PID control and so on. Meanwhile, main circuit of system, over-voltage and under-voltage protection circuit and pump protection circuit are designed, which improve the suspension control reliability of Power Magnetic Bearing.(4) According to the pure integrating link introduced decoupling control algorism for U-I model, a new integrating algorism using two first-order low-pass filters to replace pure integrating link is provided, which eliminates direct current biased error and initial errors caused by pure integrating link, and improves the rotation accuracy of rotor.(5) Rotor of Power Magnetic Bearing has high sensitivity for external disturbance, in order to achieve real-time control for system, all programs in the paper adopt assembly language, which ensures real-time characteristic of system on the basis of steady suspension.