Research On Redundant Sensor And Driving System Of Magnetic Bearing

Magnetic bearing and its supporting high-speed motor are all the research hotspots.With the continuous development of magnetic levitation technology,as one of the core links of the magnetic bearing system,the performance of the driving system plays a vital role in the stable operation of the magnetic bearings.As a result,the requirement for the design of the driving system are continuously improved.Therefore,the driving system of magnetic bearing is more and more concerned.In addition,the requirements for system reliability are also increasing.In the rotor system of magnetic bearing,the probe of the displacement sensor is installed near the rotor,and the bad working environment makes it one of the most vulnerable parts of the whole system.In order to improve the reliability of magnetic bearing rotor system,it is an effective way to design redundant sensors.In this paper,the sensor redundancy and driving system of magnetic bearing is studied and designed according to the following aspects:The control mode of the magnetic bearing driving system is analyzed.According to the design principle of the power amplifier,a new type of three level switching power amplifier is designed,which combines the advantages of the Sample-and-Hold power amplifier and the PWM power amplifier.A logic circuit that reflects the coil current and control signal is added between the PWM output waveform and the driving circuit to make the power device operate at most once in one cycle and then reduce the loss.The simulation and experimental results show that the designed circuit has fast response,good following and small ripple.Aiming at the active magnetic suspension bearing system with differential displacement sensor,the characteristics of different types of sensor faults are analyzed.The relationship between the interference force of the rotor and the interference signal of the two displacement sensors and the output signal of the controller and the output signal of the two displacement sensors is derived theoretically.And then a fault sensor detection and recognition algorithm based on LMS adaptive filtering is proposed.Simulation results show that the proposed method can detect and identify fault sensors effectively.The principle of sensor fault redundancy is studied and analyzed.A new method to identify,process and transform sensor fault signals and realize sensor redundancy function is proposed.Based on the theoretical analysis,the FPGA modular design of the sensor faultidentification circuit is designed to complete the fabrication of the redundant circuit of the sensor.The simulation and experimental results show that the filter performance and convergence performance of the modular FPGA filter are good,and the identification and redundancy functions of the sensor fault are successfully realized.