| With the wide application and development of hydrodynamic gas bearing and active magnetic bearing that both are contactless and high performance in energy power and high-end manufacturing equipment,the disadvantages of both in high speed rotating machinery are increasingly prominent,and with the further improvement of the requirements of high speed,high accuracy,high reliability and high performance,the need to develop next generation bearings is increasingly urgent.Hybrid magneticfoil bearings combine the advantages of two bearings,and eliminate the disadvantage of wear at low speed and single performance of hydrodynamic gas bearing,make up for the shortage of high speed performance and reliability of active magnetic bearing,is the ideal direction for the development of next generation high-performance bearings.At present,there are few researches on hybrid magnetic-foil bearings in the world,and there is almost no relevant experimental research on bearings and rotors in China.Based on the above,the main work of this paper for the hybrid magnetic-foil bearings are as follows:The structure design method of the hybrid magnetic-foil bearing is proposed,and the rotor test bench is built.Based on the magnetic levitation force calculation theory and the magnetic circuit design theory,combined with the foil design and manufacturing process,the hybrid magnetic-foil bearings structure and bearing electrical parameters are designed.The bearing rotor test bench is built based on the radial hybrid magnetic-foil bearings to facilitate subsequent research on the dynamic characteristics of the rotor supported by the hybrid magnetic-foil bearings.The power amplifier hardware for hybrid magnetic-foil bearings is designed.Digital power amplifier hardware for hybrid magnetic-foil bearings is designed based on three-level control method,the signal conditioning circuits of eddy current displacement sensor and current sensor are designed,the PCB of the control system hardware has been designed.The PID differential closed-loop control software program is designed based on DSP controller.This article studies the control strategy and load distribution of hybrid magnetic-foil bearings,completed the development of PID closed-loop current control software for the eight-pole coil on the TMS320F28377 D platform.This paper achieved three-level control effect by software based on F28377 D,and compared the steadystate current and current ripple of two-level and three-level strategies through theoretical calculations and simulations.This paper studied the control system and bearing rotor system through experiments.The dynamic characteristics of the designed closed-loop control system software and hardware platform is tested to verify its performance range.Start-stop test on the bearing is carried out to study the torque and take-off speed of the bearing under different static load distribution ratios,verify that the load distribution has a significant effect on the start-stop performance of the foil bearing.And the non-linear characteristics of the hybrid magnetic-foil bearings can be verified through the bearing static load cycle experiment.Rotor dynamics is experimental researched based on the rotor testbed supported by hybrid magnetic-foil bearings,the experimental results show that the load distribution has a significant suppression effect on the rotor subsynchronous vibration. |
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