Jean LE BESNERAIS 26/09/ EOMYS ENGINEERING / /

Transcription

1 Fast calculation of acoustic noise and vibrations due to magnetic forces during basic and detailed design stages of electrical machines using MANATEE software Jean LE BESNERAIS 26/09/18

2 What is electromagnetic Noise, Vibration, Harshness (e-nvh)? noise and vibrations coming from variable electromagnetic forces forces arising from the presence of a variable magnetic field : Maxwell & magnetostriction 1. variable current source 2. rotating permanent magnet 3. rotating DC current source Always present in: Induction Machines (IM) Switched Reluctance Machines (SRM) Permanent Magnet Synchronous Machines (PMSM) Wound Rotor Synchronous Machines (WRSM) Synchro Reluctance Machines (SyRM) Only present in PM-based motors I=constant Only present in WRSM Tesla SCIM [R1] Toyota Prius IPMSM [R1] Renault Zoe - WRSM Renault Zoe - WRSM 2

3 Example of an EV electric powertrain NVH: Renault ZOE = + + Overall noise Aerodynamic & mechanical noise Source separation done with LEA software [R4] Slot/pole interaction electromagnetic noise Pulse Width Modulation electromagnetic noise

4 Electromagnetic Vs Noise, Vibration, Harshness (NVH) design of e-motors Cost optimization -> thinner yoke -> higher vibrations and acoustic noise Concentrated winding design -> higher Maxwell force harmonic content -> higher risk of resonances Torque ripple is not correlated to acoustic noise Skewing can increase torque ripple and/or acoustic noise at some operating points Slot/pole combination can give 40 db difference at same torque output level: from normal conversation to (diesel-powered) lawn mower +40 db sound power level db Effect of rotor slot number on maximum noise of an induction motor using MANATEE software Electric motor designers have now to run vibro-acoustic analysis along with electromagnetic & heat transfer analysis

5 MANATEE software solutions MANATEE simulation software can be used for the electromagnetic design optimization of electrical machines including the analysis of magnetic vibrations and acoustic noise due to Maxwell forces: fast NVH calculation due to Maxwell forces during early electromagnetic design loops optimized NVH calculation in detailed design phase (automated coupling with numerical CAD models) over full operating range («noise maps») advanced post-processing for NVH root-cause analysis design optimization environments of e-motor noise mitigation techniques stator/rotor skewing pole/slot shaping current injection stator/rotor notching randomized PWM 5

6 MANATEE integration in NVH workflow MANATEE is the central point for the integrated Noise, Vibration, Harshness design process of electric powertrains (e-nvh), from basic vibro-acoustic design at e-motor level to detailed vibro-acoustic design at system level: Third-party electromagnetic design tools Third-party sound quality / psychoacoustics tools Jmag Standalone e-motor NVH solution (electromagnetics +vibro-acoustics) HeadAcoustics Third-party structural design tools Third-party NVH data acquisition tools Ansys Third-party gearbox NVH design tools Third-party acoustic design tools Oros v1.07 coupling v1.08 coupling Masta Actran

7 MANATEE demonstration: Toyota Prius 2004 case Objectives: quickly identify motor whine potential issues using MANATEE software Reference article: Z. Yang, et al., Electromagnetic and vibrational characteristic of IPM over full torquespeed range, IEMDC Proceedings, 2015 [R2] [R2] is based on Ansys workbench simulation, requiring several hours of simulation although acoustic noise is not calculated Conclusions of [R2]: potential resonances between H48 (48 times mechanical frequency) and H96 and breathing mode of the stack close to 3000 and 6000 rpm at open circuit; H24 appears at partial load but does not create significant resonance H96 H48 H24 From [R2] From [R2] 7

8 MANATEE demonstration: electrical machine definition 8

9 MANATEE demonstration: set-up of the electromagnetic model Option 1: 2,5D ANALYTICAL PERMEANCE / MMF MODEL User-defined airgap flux distribution Phase current waveforms Option 2: 2,5D SEMI-ANALYTICAL SUBDOMAIN MODEL Airgap time and space flux distribution Option 3: 2,5D FINITE ELEMENT MODEL (FEMM) Used in this demo 9

10 MANATEE demonstration: set-up of the magnetic force model MAGNETIC FORCE CALCULATION, PROJECTION AND 2D FFT r=0 r=2 r=3 Airgap time and space flux distribution Option 1: Lumped magnetic load vectors Used in this demo Option 2: Surface magnetic force densities Stator and rotor nodal or lumped Maxwell harmonic forces and moments Torque ripple Option 3: Virtual Work Principle nodal magnetic forces 10

11 MANATEE demonstration: set-up of the structural model User defined natural frequencies (e.g. experimental data) Natural frequencies automatically calculated by FEM on a 3D model Option 1: 2,5D ANALYTICAL CYLINDER MODEL Natural frequencies of the circumferential modes of an equivalent ring Dynamic radial deflections Maxwell harmonic forces and moments Static radial deflections Used in this demo Dynamic radial deflections Option 2: 3D FINITE ELEMENT STRUCTURAL MODEL Optistruct/Ansys/Nastran (commercial) or GetDP (free) S=Enveloppe fermée Vibration synthesis of radial deflections FRF calculation of main force wavenumbers 11

12 MANATEE demonstration: set-up of the acoustic model Option 1: SEMI-ANALYTICAL ACOUSTIC MODEL Radiation efficiency of an equivalent cylinder Dynamic radial deflections 2D (analytical) or 3D (FEM) spatial-averaged vibration velocity Used in this demo Sound power level Sound pressure level Option 2: NUMERICAL ACOUSTIC MODEL* Sound synthesis.wav *available in MANATEE v

13 MANATEE demonstration: set-up of the simulation workflow 13

14 MANATEE demonstration: NVH post-processing and interpretations 12f s (H48) 24f s (H96) tuto_ipmsm_01 Ansys-based results from [R2] are found within a few seconds of calculation 14

15 MANATEE demonstration: from open-circuit to partial load 6f s (H24) tuto_ipmsm_03 Ansys-based results from [R2] are found within a few seconds of calculation The breathing mode of the stack is driving noise radiation as in most EV/HEV [R3] 15

16 MANATEE demonstration: structural calculation refinement with Electromagnetic Vibration Synthesis CALCULATION OF OPERATIONAL LOADS STRUCTURAL CHARACTERIZATION ELECTROMAGNETIC MODEL 3D airgap flux distribution MANATEE 2,5D electromagnetic models (SDM, PMMF, FEMM) 2D or 3D external FEA software (e.g. Flux, Jmag, Maxwell, Magnet) Unit rotating loads identified with MANATEE r=0, ±2, ±3 STRUCTURAL MODEL Outer yoke velocity field r=0 HARMONIC FORCE PROJECTION r=2 r=3 Tangential and radial harmonic magnetic forces (magnitude, wavenumber, frequency, phase) Complex FRFs (radial & tangential) for each force wavenumber r STRUCTURAL FREQUENCY RESPONSE FUNCTIONS r=0 r=2 ELECTROMAGNETIC VIBRATION SYNTHESIS Vibration and noise spectrum with modal participation MANATEE 2,5D structural model 3D external FEA software (e.g. Optistruct, Ansys, Nastran)

17 MANATEE demonstration: structural calculation refinement with Electromagnetic Vibration Synthesis Possibility to calculate FRF using an existing FEA model or building automatically a concept stator (orthotropic, winding mass, ideal boundary conditions): tuto_ipmsm_20 12f s (H48) 24f s (H96) Automatic set-up of Prius concept stator under Ansys Updated MANATEE spectrogram based on Ansys FRF

18 Examples of MANATEE industrial validation cases Case of a traction concentrated winding PMSM with interior magnets at partial load (blind test): TESTS MANATEE -40 db Motor B Motor A Sound level during a run-up (experiments with gearbox+watercooling+converter harmonics) Sound level during a run-up (MANATEE simulation without converter harmonics) ~10 sec on a laptop Fast electromagnetic models neglecting saturation can be used in early design phase to avoid strong resonances, no need of multiphysic full numerical models

19 Case of a railway squirrel cage traction induction machine with Sound Power Level measurements according ISO3745 in semi-anechoic chamber: TESTS Sound power level during runup (including fan noise) MANATEE Sound power level during a run-up (without air cooling) ~2 sec on a laptop Fast vibroacoustic model neglecting 3D effects can be used in basic design phase to avoid strong resonances, no need of multiphysic full numerical models

20 Case of a salient pole synchronous hydroelectric generator with damper bars TESTS MANATEE 2 resonances Sound level during a run-up Sound level during a run-up ~10 sec on a laptop Fast vibroacoustic model neglecting 3D effects can be used in basic design phase to avoid strong resonances, no need of detailed multiphysic numerical models

21 Case of a traction distributed winding PMSM with interior magnets at partial load: overall SPL avg 3 micros Sound level during a run-up (experiments in non ideal acoustic conditions) Sound level during a run-up (MANATEE simulation, linear subdomain) ~10 sec on a standard PC Sound level during a run-up (MANATEE, coupling with non linear FEMM) ~5 hours on a standard PC Fast electromagnetic models neglecting saturation effects can be used in basic design phase to avoid strong resonances, no need of detailed multiphysic numerical models

22 Conclusions MANATEE is the only software specialized in the assessment of magnetic forces, magnetic vibrations and acoustic noise at variable speed, which has been extensively validated with industrial cases MANATEE gives physical insights on e-nvh, combining efficient noise troubleshooting and noise mitigation tools MANATEE can be used in pre-sizing and detailed e-machine design workflows, providing accelerated simulation times compared to a direct coupling approach contact@eomys.com r=0 r=1 r=2 =

23 REFERENCES [R1] Z. Q. Zhu Advanced Electrical Machine Technologies for Electric and Hybrid Electric Vehicle Applications - A Comparative Study, EVER Conference, 2015 [R2] Z. Yang, M. Krishnamurthy and I. P. Brown, "Electromagnetic and vibrational characteristic of IPM over full torque-speed range," 2013 International Electric Machines & Drives Conference, Chicago, IL, 2013 [R3] A. Hofmann, F. Qi, T. Lange and R. W. De Doncker, "The breathing mode-shape 0: Is it the main acoustic issue in the PMSMs of today's electric vehicles?," th International Conference on Electrical Machines and Systems (ICEMS), Hangzhou, 2014 [R4] J. Le Besnerais, C. Dendievel, Sound quality optimization of electric powertrains for e-mobility applications, CFA (French Congress on Acoustics) Proceedings, 2017