Analysis of electromagnetic force causing wheel imbalance in hub motor drive
In order to analyze the influence of factors such as motor slot shape,pole pairs,and different types of eccentricity on the unbalanced electromagnetic force of hub motors,a finite element model of surface-mounted outer-rotor permanent magnet synchronous hub motors is established.Based on electromagnetic simulation,the magnetic flux density distributions at air gap are obtained.The research results indicate that the slot opening size,symmetry of slots,and use of fillets in slots all affect the numerical values of unbalanced electromagnetic forces.Changing the number of pole pairs significantly affects the distribution of the motor's overall magnetic flux density;as the number of pole pairs increases,the magnetic flux density at the air gap increases significantly,leading to an exponential increase in unbalanced electromagnetic forces and a more uniform distribution.Different types of eccentricities increase unbalanced electromagnetic forces,where dynamic eccentricity and mixed eccentricity result in complex harmonic generation,with multiples of the fundamental period correlating with the number of pole pairs.
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