| As one of the new critical technology of aero engine in the21stcentury, more-electric enginewith high temperature active magnetic bearings (HTAMB) as the key technology has incomparableadvantages over traditional engine. The high temperature displacement sensor and digital electroniccontrol system of HTAMB are mainly studied in this paper.A differential transformer displacement sensor (DTDS) which can works under550oC ismanufactured, and the influence of high operating temperature on the DTDS mechanism andcharacteristics and the following temperature compensation technology are mainly analyzed. Thetechnical problems of sensor sensitivity increase, temperature and time drift caused by thetemperature rise are solved, and the various performances of DTDS under high temperature can beobtained through detailed calibration. The results show that reducing incentive frequency helps todecrease the sensitivity growth of DTDS when the work temperature rise from environmentaltemperature to550oC, and the sensitivity growth is about4.2%when the excitation frequency is10kHz. With the sensor sensitivity20mV/μm, the sensor maximum temperature drift is344mV andtime drift is17mV without temperature compensation, while the temperature drift becomes150mVand time drift becomes10mV after adopting temperature compensation technology. When themeasurement range is-0.35~+0.35mm with the work temperature550oC, the DTDS has the followingcharacteristics: sensitivity19.62mV/μm, linearity0.74%, repeatability±0.40%, hysteresis±0.40%andcutoff frequency800Hz. Finally, this DTDS is successfully used in a single degree-of-freedom (DOF)HTAMB test bed.For some special HTAMB application occasions that demand the rotor isolated from externalenvironment, the mathematical model of DTDS with metal layers are established. And the theoreticalcalculation formulas concerning the impacts of metal layer magnetic and electric characteristics on theDTDS performances are deduced. The DTDS performance with and without metal layers areseparately simulated on the platform of MATLAB and ANSOFT. And then the DTDS with metallayers are applied to a five-DOF AMB test bed. The research results show that the sensor sensitivityhas decreased8.18%and cutoff frequency decreased5%, while the linearity increased38.7%. Despiteof those changes, the rotor can also be stably suspended and rotated at30000r/min in the five-DOFAMB system. The impacts of displacement sensor measurement errors on the AMB work performance arestudied in detail. The measurement errors for different sensor types, installation methods andassembly locations are theoretically deducted. This research provides a certain theoretical basis for theHTAMB displacement sensor design and installation.Aimed at the displacement sensor processing circuits in AMB electronic-controlled system, theDTDS processing circuits based on FPGA are studied. The digital synchronous demodulation, Costasring and FFT transform algorithm are separately applied to the processing circuits. Then the followingsimulations and experiments are carried out in MATLAB and special static calibration devicerespectively to obtain the various performance of DTDS adopting the above three processing methods.The results show that the different processing method has its own advantages and disadvantages onthe displacement sensor performance, occupied hardware resources and delay time. So it is advisableto choose appropriate treatment methods according to different situations.The controller and power amplifier based on FPGA in AMB system are also studied. Both thePID algorithm and drive signal of tri-level switch power amplifier are simulated using MATLAB.Then the relevant experiments are carried out to study the various performance of power amplifierbased on FPGA. Finally, they are applied to a magnetic levitation ball system. The experiment resultsshow that the new type controller and power amplifier can achieve ball stable levitation.
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