Electromagnetic force density calculation in surface‐mounted PM synchronous machine with rotor eccentricity by an equivalent transformation method

Abstract

An equivalent transformation method is proposed to calculate the electromagnetic force density of surface‐mounted permanent magnet (PM) synchronous machine with static and dynamic eccentricities. It hypothetically transforms the original, eccentric machine into a concentric one with redistributed PM remanence and current density according to equivalent transformation principle. On the basis of the magnetic field of the concentric machine obtained by the subdomain method, the air‐gap flux density of the eccentric machine is then achieved. Finally, the electromagnetic force density is predicted by the air‐gap field based on Maxwell stress tensor method and analysed by the two‐dimensional Fourier transform. The effectiveness of this method is verified on both static and dynamic eccentricities conditions by the finite‐element method and experiment.

Research on Electromagnetic and Structural Characteristics of Canned Electric‐Actuated Valve Permanent Magnet Synchronous Motor under Eccentricity

“…Substituting formula (5) into formula (10), the expression of the no-load radial electromagnetic force density can be obtained as:…”

“…It can be known from (51) that when the magnetic field of order μp ± 1 (or vp ± 1) interacts with the order of vp (or μp) magnetic field, the order of the force wave generated is μp ± 1 ± νp = (μ ± ν)p ± 1. The radial electromagnetic force density under dynamic eccentricity can be deduced by (10), and (50-51) are not expanded one by one. The radial electromagnetic force F r can be expressed as [22]:…”

“…In Ref. [10], Ren et al introduced an equivalent change method to equivalently transform the magnetic flux density and current density under eccentricity conditions, and analyze the magnetic field distribution, but the three-dimensional model cannot be accurately analyzed. Zhu ZQ divided the motor model with eccentric rotor into several regions in the Refs.…”

Analysis and weakening of radial electromagnetic forces in high‐speed permanent magnet motors with external rotors based on shape functions

“…Based on the analysis of flux density harmonics, the effect of radial and tangential air‐gap magnetic field components on the radial force was analysed [7]. An equivalent transformation method for calculating the radial electromagnetic force density of a surface‐mounted type permanent magnet synchronous motor, at mixed eccentricity, is presented in Paper 8 [8]. According to the concentric magnetic field obtained by the subdomain method, the air‐gap flux density of the motor at eccentricity was derived.…”

Design and fabrication of an outer rotor permanent magnet synchronous generator with fractional winding for micro‐wind turbines

“…CT reduction techniques are simulated by using FEM on computers and the optimal CT is determined [20]. FEM analysis allows users to consider the magnetic saturation effect [21]. This method could not consider saturation, and by aiding FEM and choosing the values at the midpoint, saturation is avoided in this study.…”