Analysis of radial force harmonics in PMSM responsible for electromagnetic noise

This paper presents an analysis of the air gap radial Maxwell forces in some three-phase, inner rotor Concentrated Winding surface Permanent Magnet Synchronous Machine (CW-PMSM). Two modular winding machines and one asymmetric, winding machine are considered and simulated by a Finite Element method (FE). The air gap Maxwell pressure results from multiplication of the flux density harmonics due to magnetomotive forces and permeance linked to the magnet, to the armature, to the stator slots and their interactions. An analytical prediction tool, (Analytical Calculation of Harmonic Force Orders -ACHFO) calculates the space and time orders of theses magnetic force harmonics while identifying their origin in terms of, interactions between magnet, armature and teeth effects. Additionally, an experimental Operational Deflection Shape measurement (ODS) is realised, for one modular machine prototype, to validate the electromagnetic model results. Finally the analytical prediction of ACHFO is compared with another method to obtain the origin of low orders radial pressure based on radial flux density convolution combination approach.