Research On Electric Control System Of Heavy-load Magnetic Bearing

Heavy-load magnetic bearing requires greater maximum bearing capacity and faster force response speed,which are directly related to its electric control system.In this paper,the power amplifier and switching power supply of the electric control system for heavy-load magnetic bearing are studied in depth.Firstly,this paper analyzes the factors influencing maximum bearing capacity and force response speed of Active Magnetic Bearing(AMB),and studies the features of different power amplifier structures.A high-voltage and high-current power amplifier based on IGBT(Insulated Gate Bipolar Transistor)is developed,and the performance of the power amplifier is tested.Secondly,this paper analyzes the working principles of digital chip FPGA(Field Programmable Gate Array)and A/D conversion chip.The influence of the topologies on switching power supply is studied.A digital high frequency switching power supply based on FPGA is developed.The control software of the digital switching power supply is compiled,and the performance of the switching power supply is tested.Finally,combining the power amplifier and the switching power supply with the existing sensors and controllers in our laboratory,the electric control system of AMB is built and applied to the magnetic suspension flywheel system.The dynamic model of the flywheel system is established,the control program of AMB is compiled,and the high-speed rotation test of the flywheel system is completed.The test results of the power amplifier show that its maximum output current is 120 A,the linearity between the current control signal and the output current is 99%,and its pass band is 1300 Hz under the DC450 V power voltage.The static and dynamic performances of the power amplifier meet the needs of heavy-load magnetic bearing.The performance test results of the switching power supply show that its maximum output voltage is DC450 V,which meets the requirements of the power amplifier developed.The results of high speed test of the flywheel system show that the electric control system of heavy-load magnetic bearing can ensure the stable operation of the flywheel rotor within the working speed range.