Mechanical Design Considerations for Conventionally Laminated, High-Speed, Interior PM Synchronous Machine Rotors

Abstract

Abstract-This paper discusses mechanical design considerations that are particular to conventionally (i.e., radially) laminated rotors of interior permanent-magnet synchronous machines. Focus is placed on applications where the radial forces due to high-speed operation are the major mechanically limiting design factor. Proper design of the lamination bridges, or ribs, at the rotor outer diameter is explained in terms of the both material considerations and electromagnetic performance impact. The tradeoff of complexity versus performance associated with using strengthening ribs in the magnet cavities is discussed. The sensitivity of the mechanical design limitations to the rotor-shaft mounting mechanism is also highlighted. These effects are then analyzed using finite-element analysis for a 150-N m/6-kW integrated starter/alternator designed for operation up to 6000 r/min with an annular rotor to accommodate a torque converter or clutch assembly. This example demonstrates that it is possible to significantly improve the rotor's structural integrity using the techniques described in this paper with only a very modest impact on the projected machine drive cost.Index Terms-Electrical steel, finite-element analysis (FEA), high speed, interior permanent-magnet (IPM) synchronous machine, laminations, magnetic saturation.

Inverterless High-Power Interior Permanent-Magnet Automotive Alternator

“…This could be improved by optimising the location, number and thickness of the rotor ribs [16] and by carefully selecting the heat treatment of the laminations to trade off magnetic properties for improved mechanical strength [17]. Increasing the thickness or number of the rotor ribs will increase the magnet leakage flux and will require more permanent magnet material in the rotor to achieve the same back EMF.…”

Air-Barrier Width Prediction of Interior Permanent Magnet Motor for Electric Vehicle Considering Fatigue Failure by Centrifugal Force

“…The wider width of air-barrier makes the centerpost narrower to let the magnetic flux by means of the magnet of rotor not stay in the rotor and send it in the air gap direction to improve torque. However, because the wider width of air-barrier contributes to narrowing the centerpost, the centerpost may be broken by centrifugal force in driving the motor at high speed [10][11][12]. In this paper, aims to examine the relation by adjusting the width of air-barrier which affects the operation characteristics of the IPM motor and the resulting characteristics of the motor by using the finite element method (FEM) based on 2-D numerical analysis.…”

Determination Method of Centerpost Distance of Interior Permanent Magnet Synchronous Motor for Electric Vehicle Traction Motor considering Mechanical Safety

“…As the energy source of ecofriendly vehicles has been changed to electrical energy from fossil fuels, their driving gear has replaced the engine with motor [3][4]. The motor in driving motor for electric vehicles was used at the similar rate to the induction motor and interior permanent magnet synchronous motor (IPMSM), but since the development of hybrid electric vehicle (HEV) became active, IPMSM was mainstreamed [5][6][7].…”