Research On Position Sensorless Control System Of Axial Flux High Speed Reluctance Motor

The Axial Flux High Speed Reluctance Motor(AFHSRM)is similar to switched reluctance motor in structure and principle.The stator and rotor structures are made of silicon steel sheet superposition.The windings are centrally wound around the stator teeth and the rotor has no permanent magnet and no winding structure.Compared with permanent magnet high speed motor,AFHSRM has higher rotor mechanical strength and less eddy current loss.AFHSRM is a new type of high speed motor with high reliability,low cost and can adapt to high temperature and other harsh environment.The position sensor in the motor system not only increases the cost,but also reduces the reliability of the whole motor system,which limits the application of the motor in special fields.In order to solve this problem effectively,the AFHSRM position sensorless control technology is deeply studied in the thesis.Firstly,the structure and working principle of AFHSRM are introduced in detail,and the mathematical models of motor voltage loop and mechanical motion are derived.The basic control modes of current chopper control,voltage chopper control and angle position control are introduced.The AFHSRM ontology is simulated and analyzed by using three-dimensional finite element method,and the relevant data such as flux linkage and electromagnetic torque are obtained,which provide data support for the construction of motor nonlinear model and sliding mode observer.These lay a foundation for further study of sensorless control technology.Secondly,in order to realize the position sensorless control system of AFHSRM,the thesis deeply studies the sliding mode observer method,uses sigmoid function to replace the traditional switch function,and constructs an improved sliding mode observer,which effectively reduces the chattering of the system and improves the observational accuracy.In order to prove the superiority of the sliding mode observer method,simplified flux linkage method and pulse injection method are also studied in the thesis.The simulation models of three sensorless control methods are built in Matlab / Simulink software,and the simulation data of speed,torque and rotor position are compared.The simulation results show that the improved sliding mode observer sensorless control method has strong anti-interference ability,improves the dynamic performance of motor,and reduces the influence of strong nonlinear magnetic characteristics of AFHSRM on control accuracy.Therefore,this method is selected for the sensorless control of AFHSRM.Finally,the hardware control platform with TMS320F28335 as core controller and with IKCM30F60 GA as core power converter is built,and the required programs are compiled.The experimental results further verify the correctness and feasibility of the sensorless control system based on the improved sliding mode observer.