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This paper investigates the opportunity to use a proper geometry of Line start permanent-magnet synchronous motor (LSPMSM) that allows the same stator to be used for three different rotor structures, namely, typical, solid rotor and strange rotor. The air-gap flux density, back electromotive force (EMF), cogging torque, efficiency, starting performance and synchronization capability of the three machines are analyzed and compared. It is demonstrated that the typical rotor has the highest air-gap flux density, and the strange rotor has the lowest cogging torque and highest starting torque. In addition, the solid rotor has the lowest total harmonic distortion (THD), the highest efficiency, and the lowest cost. The size of PM and rotor structure are optimized to maximize the starting torque and efficiency of the solid rotor LSPMSM based on response surface method (RSM). Finally, the solid rotor LSPMSM is prototyped to verify the results of the finite element analysis. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to optimize the PM arc ratio of consequent pole permanent magnet vernier machine (CP_PMVM). The operation principle of the CP_PMVM is discussed. An optimization parameter K related to the PM arc ratio is derived. For the CP_PMVM, the amplitudes of the 4th and 14th order harmonics of the air-gap flux density, the amplitude of the back electromotive force (back-EMF) and the average torque all have positive correlations with K. The optimal PM arc ratio is 0.64. The three phase inductances are approximately constants, and the d-axis inductance is equal to the q-axis inductance. The PM flux linkages are sinusoidal. The no-load back-EMF waveform of the measured phase is nearly sinusoidal. The gear ratio of the CP_PMVM evaluated from the back-EMF is close to the design value. Furthermore, a controller according to the mathematical model is designed. The CP_PMVM vector control with a sliding-mode (SM) speed controller exhibits a smooth starting, and has an anti-jamming capability. [ABSTRACT FROM AUTHOR]

This paper presents an analytical method to calculate the air-gap magnetic flux density distribution of a permanent magnet (PM) vernier motor. For this purpose, the air gap permeance, the magneto-motive force (MMF) of rotor magnets and the MMF from stator winding are respectively expressed in the form of Fourier series. The permeance function whose values of the all harmonics are given in terms of geometry, is utilized with the MMF of PMs to analyze the air gap flux density of the vernier machine. In addition, the role of each harmonic components of flux density in the production of back electromotive force (back-EMF) and torque is examined. Finally, the effectiveness and accuracy of the derived expressions are checked with the help of finite element (FE) analysis. [ABSTRACT FROM AUTHOR]