MANATEE software | e-NVH algorithms |
---|---|

Sub-module |
ALG.LEA |

Function |
Load Extrapolation Algorithm (LEA) |

Validation |
ALG_001 ALG_018 ALG_049 |

See also |
ALG.LIA Load Interpolation Algorithm |

### Objectives

The accurate calculation of noise and vibrations of electric motors requires to evaluate their **vibro-acoustic behaviour at variable speed, taking a high number of speed steps** to correctly catch structural resonances. This usually represents a high computational load, as operational magnetic loads must be updated at each operating point.

MANATEE Load Extrapolation Algorithm (LEA) algorithm aims at **speeding up variable speed calculation of operational magnetic loads** in early design phase of e-motors. Using LEA, variable-speed operational magnetic loads can be obtained based on a few single speed simulation and then extrapolated to the full speed range.

**Illustration of spectrogram synthesis technique in MANATEE software**

### Description

LEA is as accurate as quasi-static speed by speed load calculation when **the evolution of the magnetic excitation with speed can be predicted** in terms of magnitude and frequencies (including rotation direction). As an example, the magnitude of the flux density and resulting Maxwell stress in an **open circuit or fixed current angle** permanent magnet synchronous machine is independent of speed (except in case of strong dependency of B(H) curve with frequency): excitation frequencies of magnetic force harmonics change with speed (generally proportionally) but their magnitude is unchanged.

LEA accounts for specified control law (e.g. Id/Iq function of speed) and assume no change on saturation level at variable speed. To account for saturation and load effects more accurately at variable speed, especially in more detailed stages, using ALG.LIA (Load Interpolation Algorithm) instead is recommended to speed up load calculation for each operating point.

### Technical details

Assumptions of the Load Extrapolation Algorithm can be found in What is Load Extrapolation Algorithm (formerly called synthesized spectrogram)?.

### Graphical post-processing

The complete list of plot commands is available on MANATEE plot commands webpage.