Research On Linear Primary Permanent Magnet Motor And Control System For Elevator

As a transportation equipment,the elevator is essential for the high-rise building in the modern city.With the development of urbanization,the urban population is growing by the day and the urban buildings are becoming larger and higher to adapt to the tendency of urbanization.In the high-rise building,the existing traction elevator with steel ropes suffers from low transportation efficiency,long waiting time,large footprint,and limited lift height,making the research and development of new elevator become more and more important.The ropeless elevator powered by linear motors doesn't need steel ropes and incorporates multiple cabins in the same elevator hoistway.Therefore,the ropeless elevator can overcome the aforementioned disadvantages of the traction elevator.The linear induction motor,linear synchronous motor,and linear switched reluctance motor are mainly used to power the ropeless elevator.As a new type of linear motor,linear primary permanent magnet motor has permanent magnets and armature windings on the short mover and the long stator is only made of iron.Hence,it is suitable for the long-distance drive system,such as the ropeless elevator.In this thesis,the linear flux-switching permanent magnet motor is proposed to power the ropeless elevator.The fruits of this thesis are as follows:1.By considering the high requirements of thrust force,thrust force ripple and fault-tolerant capability with respect to the linear motor in the ropeless elevator and analyzing the existing compact thin yoke linear flux-switching permanent magnet(CTYLFSPM)motor,modular thin yoke linear flux-switching permanent magnet(MTYLFSPM)motor is proposed and the operating principles are illustrated.Based on the finite element method,the magnetic field,back electromotive force,inductance,thrust force,end-effect,efficiency map and so on are analyzed.The results show that the proposed MTYLFSPM motor exhibits symmetrical back electromotive force,good thrust force performance,and strong fault-tolerant capability.2.To improve the optimization efficiency of the finite element model,the existing surrogate-based optimization(SBO)algorithm is investigated and an improved SBO algorithm is proposed.The proposed algorithm adopts new infill criterion and makes full use of the computer parallel computing to improve the convergence of the algorithm.Numerical experiments on test functions validate the effectiveness of the proposed improved SBO algorithm.3.Taking a ropeless elevator model as the application object,the MTYLFSPM motors and CTYLFSPM motors with the different mover and stator pole pitch ratios ?m/?s are optimized with the proposed improved SBO algorithm.The details of the current density determination and optimization objective creation during the optimization process are presented.The optimization results show that the best pole pitch ratio of the MTYLFSPM motor is ?m/?s=6.5/6,and the best pole pitch ratio is ?m/?s=7/6 for the CTYLFSPM motor.These two optimized motors exhibit close performance,but the former has a strong fault-tolerant capability that the latter does not possess.A prototype ?m/?s=6.5/6 MTYLFSPM motor is designed.4.The MATLAB/Simulink model considering saturation and spatial harmonics of the designed MTYLFSPM motor is built.The control strategy combining vector control and active disturbance rejection control technique is proposed.Then,the simulation platform of the drive system is built.Simulating cabin moving up and down,the displacement and velocity compound control is investigated based on the simulation platform.5.The experimental platform is built based on the designed MTYLFSPM motor.The hardware circuit and software program are designed based on d SPACE controller.For the prototype,the back electromotive force,resistance,inductance,detent force,static thrust force,and temperature rise are investigated experimentally.The velocity closed-loop control displacement and velocity compound control are performed.6.For the elevator powered by MTYLFSPM motor,the brake control in the case of an electrical outage and the failed mechanical brake is investigated.The braking method using external braking resistors is adopted.For the MTYLFSPM motors with the silicon steel sheet stators and A3 mild steel stators,the resistances are calculated to stabilize the falling velocity of the cabin.Further,for the MTYLFSPM motor with A3 mild steel stators,the brake control in case of an electrical outage,failed mechanical brake and external resistors is analyzed.The results show that the braking force introduced by the eddy current in the stators can slow down the cabin and stabilize the falling velocity.The experiments are conducted to validate the analytical results.7.The sandwiched thin yoke linear flux-switching permanent magnet(STYLFSPM)motor is proposed.The proposed motor exhibiting high thrust force performance combines the characteristics of the rotary sandwiched flux-switching permanent magnet motor and MTYLFSPM motor.Based on the finite element method,the operating principles,electromagnetic performance and efficiency map are analyzed.With the proposed improved SBO algorithm,the STYLFSPM motors with different pole pitch ratios are optimized.The optimization results show that the STYLFSPM motor with ?m/?s=8/6 exhibits the best performance,which is 30% higher than that of the optimized CTYLFSPM motor and MTYLFSPM motor.