Acoustics of a 6-phase transversal flux outer-rotor switched reluctance drive

Switched reluctance machines are appealing to the automotive industry due to their cost-efficiency. However, switched reluctance traction drives are likely to be unacceptably noisy. The aim of this paper is to prove that transversal-flux switched reluctance drives exhibit great vibro-acoustic benefits compared to conventional radial-flux reluctance machines. The principle of modal superposition is used to simulate run-up spectrograms for both a transversal-flux machine and a radial-flux benchmark. Modal transfer functions are determined by structural finite-element simulation. The modal excitations stem from the simulated magnetic forces during the run-ups. The comparison of the two machine types highlights the acoustic benefits of the transversal-flux machine. These advantages make it a cost-efficient and at the same time acoustically acceptable alternative to the customary permanent-magnet or induction machines in today´s electric-vehicle market.