Study On Design And Analysis Of Novel Permanent Magnet Vernier Wind Generator

Permanent magnet vernier machine(PMVM),as one novel embranchment of low speed large torque PM synchronous machine(PMSM),which has a bright future in driect drive industrial applications of wind power generation and electric vehicle by incorporating the magnetic field modulation into PMSM.The researches on its topology,electromagnetic design and low speed large torque characteristic are significant in both theory and engineering application.Based on the comprehensive investigations of flux focusing magnetic gear(MG)and fractional slot concentrating winding(FSCW)PMVM,a novel type of flux focusing multi-tooth splitting concentrating winding PMVM(FFMSCW-PMVM)is proposed,designed and optimized in this dissertation,which holds the merits of high torque density and simple topology.Also,the generalized design methods and principles are discussed.The concept of 'original PMSM' for MSCW-PMVM is presented through their electromagnetic similarity analysis,both of which have same stator tooth numbers.As a result,the performance of derivative MSCW-PMVMs can be rapidly predicted by their original machines.The unbanced magnetic pull(UMP)of original PMSM is calclulated by analytical method,and its accuracy is verified by the finite element analysis(FEA).Then,the relathionship between machine parameters and UMP is investgited and analyzed.A FFMSCW-PMVM prototype is manufactured and tested,which verifies the correction of related design and analysis.In addition,several methods are proposed to overcome the common problem of low power factor of MSCW-PMVM.The main contents and fruits of this dissertation are summarized as follows:At the beginning,the origination and development of magnetic gear machine(MGM)and PMVM are discussed and summarized.Especially,the merits of PMVM for low speed direct drive are analyzed.Secondly,the working principle of MG,MGM and PMVM is expressed uniformly from magnetic field modulation group view,which solves the issues of existing researches focusing on individual or separately comparisons.The conversion criterions among MG,MGM and PMVM are systemically discussed and verified by using FEA.One novel hybrid PM flux focusing MG with 24/19/5 slot and pole combination is proposed based on the detailed analysis and comparions of existing MG topoligies,the flux modulation poles(FMPs)number,the PM pole-pair numbers of outer stator and inner rotor of which are 24,19 and 5.Differing from the traditional MGs,the proposed MG keeps the flux modulation ring and inner rotor rotating,and the PM materials of inner rotor and outer stator are respectively NdFeB and ferrite to reduce the cost,.The parameters and torque-angle characteristic of the proposed MG are optimized and calculated,respectively.A gear ratio factor method is put forward to evaluate the performance of MG.For FSCW-PMSM and MSCW-PMVM with same stator teeth numbers,the electromagnetic similarity analysis is implemented through the analyzing no-load magnetic field distribution,winding connection,induced electromotive force(EMF)and cogging torque.The 'original PMSM' concept of MSCW-PMVM is proposed,which can be used to make a rapid prediction of the performance of derivative PMVMs.Moreover,the forming reason and characteristics of UMP for original FSCW-PMSMs are studied.The analytical expressions of UMP under no-load state are also derived,and the analytical results match well with those of finite element analysis(FEA).Based on the above analysis of the 24/19/5 MG,a novel FFMSCW-PMVM is proposed,designed and optimized.The power dimension expressions of the proposed machine are derived and calculated,and the corresponding design parameters are optimized.The.electromagnetic properties of the proposed machine are calculated,such as magnetic field distribution,air-gap magnetic density,magnetic flux linkage,no-load induced EMF,winding inductance,cogging torque and external characteristic.And then the thermal analysis model of the proposed machine is established with the aid of FEA,and the thermal loading checking is carried out.Finally,a prototype is fabricated and measured.The corresponding no-and on-load experiments are conducted,which verify the correctness and effectiveness of theoretical derivation,calculation and analysis.