TY - GEN

T1 - Methodology to evaluate the mechanical stress in high speed electric machines with buried magnets

AU - Gerlach, Martin Enno

AU - Zajonc, Maximilian

AU - Ponick, Bernd

N1 - Funding Information: Supported by: Federal Ministry of Economic Affairs and Energy on the basis of a decision by the German Bundestag.

PY - 2020

Y1 - 2020

N2 - High speed electric machines are gaining in importance due to their high power density. The evaluation of the mechanical stress in the rotor is one crucial part of the design process for this type of machines. It is insufficient to evaluate just the static mechanical stress at maximum speed. The dynamic mechanical stress between the state of standstill and maximum speed needs to be considered as well to evaluate the high fatigue strength of the rotor.One criterion that is commonly used to analyze the dynamic load in a material is the Smith diagram. In this work, a new methodology is introduced to evaluate both, the dynamic and the static mechanical stress, in the rotor of an high speed electric machine. First, the von Mises stress criterion is used to examine the static mechanical stress in the rotor core. Then, the Smith diagram is used to evaluate the dynamic mechanical stress and the high fatigue resistant of the rotor.The methodology is then applied to a high speed electric machine with buried magnets in v-shape for analyzing the state of stress. Therefore, the state of stress is calculated using an FEM simulation model. It can be seen that high dynamic stress occurs at the bridges in the rotor. The stress alternates with up to σalt = 300 MPa. The design is though limited due to the high static stress at the edge bridge of the magnet slot.

AB - High speed electric machines are gaining in importance due to their high power density. The evaluation of the mechanical stress in the rotor is one crucial part of the design process for this type of machines. It is insufficient to evaluate just the static mechanical stress at maximum speed. The dynamic mechanical stress between the state of standstill and maximum speed needs to be considered as well to evaluate the high fatigue strength of the rotor.One criterion that is commonly used to analyze the dynamic load in a material is the Smith diagram. In this work, a new methodology is introduced to evaluate both, the dynamic and the static mechanical stress, in the rotor of an high speed electric machine. First, the von Mises stress criterion is used to examine the static mechanical stress in the rotor core. Then, the Smith diagram is used to evaluate the dynamic mechanical stress and the high fatigue resistant of the rotor.The methodology is then applied to a high speed electric machine with buried magnets in v-shape for analyzing the state of stress. Therefore, the state of stress is calculated using an FEM simulation model. It can be seen that high dynamic stress occurs at the bridges in the rotor. The stress alternates with up to σalt = 300 MPa. The design is though limited due to the high static stress at the edge bridge of the magnet slot.

KW - High fatigue strength

KW - High speed electric machines

KW - Hooke's law

KW - Mechanical stress

KW - Smith diagram

KW - Static strength

KW - Von Mises stress

UR - http://www.scopus.com/inward/record.url?scp=85091190509&partnerID=8YFLogxK

U2 - 10.1109/speedam48782.2020.9161946

DO - 10.1109/speedam48782.2020.9161946

M3 - Conference contribution

AN - SCOPUS:85091190509

SN - 978-1-7281-7018-3

SN - 978-1-7281-7020-6

SP - 77

EP - 84

BT - 2020 International Symposium on Power Electronics, Electrical Drives, Automation and Motion, SPEEDAM 2020

PB - Institute of Electrical and Electronics Engineers Inc.

T2 - 2020 International Symposium on Power Electronics, Electrical Drives, Automation and Motion, SPEEDAM 2020

Y2 - 24 June 2020 through 26 June 2020

ER -