Study On Bipolar Magnetic Field Crosslinking Transverse Flux Permanent Magnet Machine

Transverse flux permanent magnet machine has been attracted wide attention by researchers in recent years due to its characteristics in low speed range and great torque density;however,it has the disadvantages of low stator space and magnet utilization.This thesis studies the novel machine called bipolar magnetic field crosslinking transverse flux permanent magnet machine with ‘9' shaped stator structure improving the stator space utilization effectively,and the crosslinking bipolar magnetic fields between stator core and rotor magnets thus enhancing the power density and torque density.At first,the structure and operating principle of the traditional transverse flux permanent magnet machine and the bipolar magnetic field crosslinking transverse flux permanent magnet machine are compared.And then the highlight structural merits of the novel machine against conventional transverse flux magnet machine are illustrated in detail including higher stator space utilization and crosslinking bipolar magnetic field.Secondly,the mathematical model of the novel machine is built by simplifying the magnetic circuits established with equivalent magnetic field method on the basis of motor structure and operating principle,by which the expressions of primary motor parameters are deduced covering no-load EMF,torque as well as inductor expressions to obtain the analytical calculating results of the main parameters of the designed prototype motor.Then,finite element software is used to analyze the case of no-load operation such as EMF and cogging torque and also the structural parameter influence on motor torque.Furthermore,comparing the above analytical expressions with the simulation results of the designed prototype motor,the effectiveness of the analytical expressions are verified.Besides,the performance comparison between the bipolar magnetic field crosslinking transverse flux permanent magnet machine and the conventional transverse flux permanent magnet machine are carried out so as to verify that the torque density can be promoted by the new structure machine.Finally,the design approach of the novel machine is discussed.By further inferring the obtained parameter expressions,the main dimension expression can be acquired and therefore the design approach of the main dimension is given.In addition,the design approaches of the specific structure that includes windings,stator core,permanent magnet and rotor core are involved.