Design And Efficiency Optimization Of Permanet Magnet Reluctance Synchrous Machine For Electric Vehicle

The Permanent Magnet Reluctance Synchronous Machine(PMRELSynM)has been widely applied in the Electric Vehicle due to the high torque density,wide speed range and high efficiency.This thesis focuses on analyzing and investigating the mechanism between the design parameters and the efficiency characteristics of the PMRELSynM,which aims at improving the efficiency and reducing the material cost.The guidelines of the key design parameters toward high efficiency are provided,and a multiple objectives optimization method which makes a tradeoff between the performance and material cost is proposed.The main research work of this thesis is as follows:1.The electromagnetic model of the PMRELSynM is built to obtain the torque,flux density in the airgap and iron.It is verified by the Finite Element Analysis(FEA)and can be used as the basis to analyze the loss and efficiency characteristics.2.The losses distribution of the PMRELSynM is analyzed,and then the main parameters which have great influence on the loss characteristics are selected to derive the loss functions.The procedure to create the efficiency is built by combining the electromagnetic model and loss functions of the PMRELSynM.The efficiency map of the PMRELSynM can be obtained effectively considering the voltage and current limits.3,The loss coefficients of the PMRELSynM are obtained by stripping the operating condition from the loss functions,and then the loss evaluation system is built as a tool to investigate the mechanism between the parameters and the efficiency characteristics.The theoretical basis is established to analyze and design the PMRELSynM,and the guidelines of the key parameters are given.4.The multiple objectives optimization based on the driving cycle is launched to improve the efficiency and reduce the material cost.To reduce the computation and time cost,the loss evaluation system is brought to the optimization.The prototype of the PMRELSynM with two flux barriers is manufactured and tested under noload and load conditions to verify the analysis.5.The bypass-rib is proposed.The main parameters of the bypass-rib are introduced and the operating principle is described using the FEA method.The influence on the anti-demagnetization ability,constant power range and the efficiency under flux weakening is investigated,and the criteria of the bypass-rib is summarized.6.The characteristics of different topologies of permanent magnet machines are analyzed and compared.The difference of the mechanism between the parameter and efficiency characteristics are described,which is the useful reference to the topology selection.