Research On The Position Sensorless Control System Of A Novel Axial Field Flux-switching Machine

Hybrid Excitation Axial Field Flux-Switching Permanent-Magnet(HEAFFSPM)machine is a new type of stator-typed double salient permanent magnet machine,which has the advantages of large power density,high efficiency,strong fault tolerance and wide speed range,so it has a good application prospect in the field of electric vehicles.In this paper,a 6 / 14 pole HEAFFSPM machine is taken as the control object,and its position sensorless control system is studied.Firstly,the topology of the HEAFFSPM machine is introduced,the working principle of the machine is explained,and the mathematical model of the HEAFFSPM machine is established in three-phase stationary abc coordinate system,two-phase stationary αβ coordinate system and two-phase rotating dq coordinate system,respectively.Secondly,based on the model reference adaptive system(MRAS)principle,the HEAFFSPM machine position nsensorless control system of the stator current and stator flux MRAS algorithms are constructed respectively.Based on MATLAB / Simulink and Real Time Unit(Rtunit)controller,the simulation and experiment of the two control methods are studied,and the results of simulation and experiment are compared and analyzed.Then,in order to osolve the shortcomings of large position error,insufficient lowspeed performance and poor load performance of the MRAS algorithm in the HEAFFSPM machine position sensorless control system,an improved MRAS position sensorless composite control method is proposed.In the medium and high speed range,the traditional stator current MRAS is improved to estimate the rotor speed and position information by adding excitation winding,whilst increasing the load capability;in the zero and low speed range,the pulse high-frequency voltage injection(PHFVI)method is used to estimate the rotor speed and position information;the control strategy based on weighted algorithm is adopted to realize the smooth switching between the medium high speed and zero low speed domains.In addition,based on MATLAB / Simulink,the dynamic and steady-state performance of the HEAFFSPM machine control system are studied under the PHFVI,the improved MRAS,and the composite control method,respectively.Finally,the hardware circuits of rotor detection,signal sampling,drive and power supply are designed by the software of Altium designer 13.The programs of the control system are made by MATLAB / Simulink and Rtunit Toolbox.The experimental platform of position sensorless control system for HEAFFSPM machine is built on the basis of Rtunit controller,on which the improved MRAS position sensorless composite control method is researched.The experimental results verify the composite control method can carry out full-speed operation of the HEAFFSPM machine with position sensorless,reduce the rotor position and speed errors,and improve the load capability of the system.The research results lay the foundations theoretically and practically for the application and development of HEAFFSPM machine in the field of electric vehicles.