Research On Control System Of Linear Flux-switching Permanent Magnet Motor For Elevator

In recent years,with the accelerated process of urbanization in china,more and more highrise and super highrise buildings are appeared,the wire rope hoist system of traditional traction elevators,because of its inherent limitation,can no longer meet the requirements of people.As a result,the ropeless elevator driven by linear motor has drawn great attention for the following reasons: it has no restriction on lifting height and no need for intermediate conversion devices.Accordingly,the linear-motor-driven elevator is an important direction for future development of elevators.Linear flux-switching permanent magnet(LFSPM)motor is a new type of permanent magnet linear motor,in which both the magnets and armature windings are located in primary mover,while the long stator only consists of iron core.Hence,LFSPM motor has the advantages of simple structure,low cost,high power density and high efficiency,which is especially suitable for long stator applications such as ropeless elevator and rail transportation.The key technicial issues on a modular double-sided LFSPM motor control system are investigated in this thesis.Then the hardware for the control system based on digital signal processor is designed.The simulation and experimental verification of the control system are carried out.The main research contents of this thesis include the following aspects:1.The basic structure,working principle and static characteristics of the LFSPM motor are firstly explained.Then the mathematical model of the LFSPM motor is established in the three-phase stator stationary reference frame and two-phase rotating reference frame.2.The vector control strategy of the LFSPM motor is studied and the thrust ripple of the motor is analysed.Then the mathematical model of the cogging force is established and a method based on current harmonics injection is proposed to compensate the main component of cogging torque.3.The principle of sensorless control method based on model reference adaptive system(MRAS)is explained,and an improved speed estimator based on artificial neural network(ANN)is proposed.Then the initial rotor position estimation of LFSPM motor based on high frequency signal injection is investigated.4.Aiming at the energy conservation issue when the LFSPM motor operates as a generator,the energy feedback system based on the single phase PWM rectifier is investigated.Firstly,the working principle of the single phase PWM rectifier is analyzed and the mathematical model in the two-phase rotating reference frame is established.Then a double closed-loop control strategy and a method to restrain the harmonics of AC-side input current are proposed.5.The simulation model of the control system of LFSPM motor for elevator is established based on Matlab/Simulink,and the hardware for the control system based on digital signal processor TMS320F28335 is designed.Finally,both simulation and experimental results verified the feasibility and effectiveness of the proposed control strategies.