Research On Primary Staggered Double-Sided Linear Flux-Switching Permanent Magnet Motor And Its Control

With the rapid growth of economy and the continuous development of urbanization construction process,the number of high-rise and super high-rise buildings in China is increasing,and the height is constantly refreshing.As necessary transportation equipment in modern city life,elevators and the related industries have developed rapidly.With the continuous increase of building scale,the disadvantages of traditional traction elevator are becoming more and more prominent,which bring great challenges for reducing waiting time and improving elevator operation quality.By installing the stator and the mover of a linear motor in the hoist way and on the car respectively,ropeless elevators can be obtained,which have the advantages of theoretical unlimited lift height,easy to realize multiple cars in one hoist way,high operating efficiency,good stability and strong fault-tolerant capability.So the ropeless elevator drive by linear motors is an effective solution to the inherent defects of traction elevators.In primary permanent magnet(PM)linear motors,the armature winding and the PMs are located on the primary side,and secondary side is only composed of cheap iron core.When the short primary side and long secondary side structure is adopted for ropeless elevators,the system can not only inherit the characteristics of high efficiency and high power density from linear PM motors,but also possess the advantages of simple structure and low cost of both linear induction motors and linear switched reluctance motors.So this kind of motor has very wide potential application prospects in the field of elevator.Thus,a primary staggered double-sided linear flux-switching permanent magnet(PSDS-LFSPM)is proposed in this thesis.Based on the presentation of motor topology,the operating principle is explained and the design method is discussed.By using finite element method(FEM),the dimension parameters are determined and the electromagnetic performances are calculated and analyzed.Also the drive control strategy is discussed.The main research content of this thesis can be summarized as follows:1.In order to satisfy the demands of high payload ratio,low thrust force ripple and high fault-tolerant capability,a novel PSDS-LFSPM motor is proposed.Two kinds of winding configurations are proposed for the proposed motor based on the general airgap magnetic field modulation theory.By comparing the performances of the motor with the different pole combinations,the different winding configurations and the different end additional teeth,the topology of the PSDS-LFSPM motor is determined.2.The mathematics models of magnetomotive force and magnetic permeance are established,based on which the PM flux density in airgap,the PM flux linkage,and the no-load EMF can be analytical calculated.Thus the power equation of the proposed PSDS-LFSPM motor based on the dimensions can be obtained for the initial motor design.3.In order to improve the payload ratio of the motor,the influence of key size parameters of PSDS-LFSPM motor on performances is analyzed in detail by FEM.The motor performance variation with the thickness ratio of the primary side to the total motor is investigated.Then the design parameters of the prototype are obtained based on the comprehensive consideration of the load ratio,the thrust ripple and the PM utilization ratio.4.To illustrate the advantages of proposed PSDS-LFSPM motor,the basic electromagnetic performances are calculated and analyzed by FEM,and compared with a conventional double-sided C-core linear flux-switching PM motor,which is designed by using the same mothed,thus further proving that the PSDS-LFSPM motor possesses the advantages of higher load ratio,lower thrust ripple and higher PM utilization ratio.5.According to the special double-sided structure and the high reliability requirement for the motor system in elevator field,the dual three-phase operation mode of PSDS-LFSPM motor is proposed and the corresponding mathematical model is derived.Then,the fault-tolerant control principle is introduced,and the fault-tolerant control strategy of PSDS-LFSPM motor is deduced and verified by simulation.6.The PSDS-LFSPM motor is prototyped and the corresponding test platform is built.Then experimental tests are carried out,including no-load induced electromotive force,inductance,static thrust and dynamic characteristics under different working conditions.Based on the experimental results,the correctness and validity of motor design and theoretical analysis can be verified.