New Rotor Topologies for Electromagnetic Forces and Acoustic Noise Reduction of claw Pole Alternators

다국어 초록 (Multilingual Abstract)

This paper proposes a new rotor topology to reduce the electromagnetic forces and acoustic noise of automotive claw pole alternators. A noise bench test was first conducted for a 12-pole/36-slot claw pole alternator and the characteristics of the noise were analyzed. The analytical expression of electromagnetic forces was then derived, and the noise generation mechanism was illustrated theoretically. According to the distribution of the electromagnetic forces on the stator surface, a new rotor structure with rotor claw poles offset was proposed to decrease the force harmonics. Simulation results showed that when the rotor claws of N pole and S pole were offset in the same direction which was consistent with the direction of rotor rotation, the electromagnetic noise would be reduced by 6.7 dB(A), without sacrificing the output current. However, when the rotor claws were offset in the opposite direction, the electromagnetic noise could not be effectively reduced and was even slightly increased. The topology proposed in this paper provides an effective solution for the design and optimization of electromagnetic noise in claw pole alternators.