Multiphase Fractional-slot Concentrated Winding Permanent Magnet Machines Modeling And Simulation

Simulation is an effective auxiliary mean of the design and drive of novel machines. As one of novel machines, multiphase permanent magnet machines take the advantages of both of multiphase machines and permanent magnet machines, and it has a promising prospect. Based on the multiphase fractional-slot concentrated full-pitch winding permanent magnet machine(MFPM), this paper researches the modeling of multiphase permanent magnet machines whose back electromotive force(EMF) is flat-topped and the performances when it is injected with harmonic currents, laying a good stone for the following project work.First of all, this paper introduces the construction and performance of MFPM with quasi- trapezoidal permanent magnets(PM) and points out that this machine features flat-topped EMF and the torque density can be improved by harmonic current injection. Multidimensional d-q model of the machine is then built and based on this model, the current and torque performances of MFPM excited with sinusoidal and harmonic current are analyzed and compared, verifying that the injected harmonic current produce additional torque and improves the torque density. However, the result may have some deviations because the multidimensional d-q model of MFPM neglects the higher harmonics of EMF and the variation of inductances.Secondly, the modeling methods of phase variable model(PVM) of machine, parameter calculations and searching methods are analyzed and the PVM of MFPM is built based on circuit components. According to the characteristics of the multidimensional d-q model, the paper builds PVM which has higher accuracy for MFPM. Consequently, simulation results based on the two models are compared and the effect of neglecting the higher harmonics of EMF and inductance variation by multidimensional d-q model are investigated. For the sake of improving accuracy of PVM, the fixed permeability method for inductance calculation are compared with the methods in related literature. What's more, multi-lookup tables are used for inductance searching to improve the accuracy of inductance.Finally, the FLUX-SIMULINK combined simulation model are set up to further analyze the machine performance and verifies the feasibility of multiphase machine PVM. Methods and steps for the establishment of the combined simulation model are analyzed and summarized, and the performances of MFPM and its variable-speed system under different working conditions are simulated using the FLUX-SIMULINK combined simulation model. Comparison of the results with those obtained using PVM shows the feasibility of multiphase PM machine PVM. In addition, the characteristics and applicable scope of the mentioned three models of MFPM are analyzed and compared, providing guidelines for the following research work.