Research On Flux-Modulation Brushless Dual-Electrical-Port Dual-Mechanical-Port Permanent Magnet Machine

In recent years,with the development of modern emerging industries such as new energy power generation and new energy vehicles,multi-electrical-port multi-mechanical-port system has become a new research direction.It operates through multiple mechanical and electrical ports to achieve rich functions and meet the requires of emerging industries.The multi-electrical-port multi-mechanical-port system has the characteristics of multifunction and multi-motion-mode.However,due to the combination of "multiple motors and mechanical components ",this kind of system has the problems of increasing volume and weight,reduced reliability and frequent maintenance.In order to solve these problems,the researchers proposed a multi-function integrated machine system,which represented by the flux-modulation brushless dual-electrical-port dual-mechanical-port(DEP-DMP)permanent magnet machine,using one machine instead of "multiple machines and mechanical components".It has the advantages of high compactness,high integration,and contactless power transmission,which has a good application prospect.In this paper,performance improvement of DEP-DMP machine is taken as the main line.The basic theory,topology construction,design and structural innovation are carried out.The main research contents and contributions are as follows:(1)This paper reviews and summarizes the research of the DEP-DMP machine and high-performance flux modulation machine.Then,a general topology construction method of DEP-DMP machine based on the integration of the flux modulation machine metamodel is proposed to solve the problem that the existing topology is random and difficult to be studied by regular magnetic circuit optimization method.The integration method of the electrical-port and the mechanical-port and the performance characteristics of the integrated structure are summarized.By changing the metamodel motion module,relative position and port integration,a variety of the DEP-DMP topologies are constructed.It realizes the generalization of the existing topology.Besides,a series of novel topologies represented by Spoke-Array DEP-DMP machine are proposed.(2)The air-gap mapping model of the DEP-DMP machine is proposed to solve the problem of difficulty in quantitative calculation caused by double air-gap,dual rotor and dual winding structure.In the air-gap mapping model,the reluctance inner rotor with slot-effect is mapped to the excitation magnetomotive force(MMF)of the outer rotor through the inner air-gap permeance function and nodal equations,which simplifies the double air-gap equivalent magnetic circuit model into a single air-gap model.Combined with the MMF-permeance model,the air-gap flux density,back-EMF and average torque expression are derived.The machine size equations are further deduced,and the main parameters affecting the performance of the machine are described.This provides theoretical guidance for the performance improvement of the DEP-DMP machine(3)A novel machine design method of constant torque ratio based on electric load distribution is proposed to solve the problem that the influences of the dimension parameters on the inner and outer rotor torques are negative,resulting in difficult to obtain the comprehensive optimal design.The origin of the proposed design method is explained from the structural characteristics and application requirements of DEP-DMP machine.Then,the general design procedure is established.The influence of some dimension parameters,including stator split ratio,magnet height,inner rotor slot opening factor,on outer rotor torque is studied and the optimal design parameters are determined.According to this,a prototype is built,and the experiment verifies that the machine can realize the independent control of the torques and speeds of the two mechanical-ports.(4)The dual-electrical-port integrated winding is proposed to solve the problem of processing difficulty,low slot filling factor and easy insulation breakdown caused by two windings sharing one stator.The integrated winding is to replace the original two armature windings,and improve the torque density.In this paper,it is shown that two independent controllable armature magnetic fields with differnet pole-pairs can be generated by passing a current with two components into the integrated winding.Then,the general construction method of the integrated winding,the phase separation rule and the feasible pole-slot combinations of the six-phase integrated winding are given,and the validity of the integrated winding is verified by finite element analysis(FEA)and prototype experiments.It is proved that the efficiency of the integrated winding DEP-DMP prototype is higher than that of the dual-winding prototype under the same torque and speed.