2015_04_16 Noise and vibration DSA of electrical machines
Transcription
2015_04_16 Noise and vibration DSA of electrical machines
EOMYS ENGINEERING Noise and vibration Dynamic Signal Analysis on electrical machines 15/04/2015 LE BESNERAIS Jean SOURON Quentin www.eomys.com © EOMYS ENGINEERING 2014-2015 1 A. EOMYS ENGINEERING B. Why Dewesoft ? C. Magnetic acoustic noise and vibrations in electrical machines D. Measurement set-up E. Acquisition software set-up F. Post-processings G. Conclusion EOMYS ENGINEERING 2014-2015 (C) ©EOMYS ENGINEERING 2013-2014 2 A. EOMYS ENGINEERING Overview • Young Innovative Company* created in may 2013 • Located in Lille, North of France • Activities : engineering consultancy & applied research specialized in electrical engineering • Sectors : transportation (railway, automotive, marine, aeronautics), energy (wind, hydro), industry *"Jeune Entreprise Innovante": the French government recognises that EOMYS runs significant R&D activities © EOMYS ENGINEERING 2014-2015 3 Services Analyze and solve your multi-physics technical issues • • • • multiphysics experiments (investigation, pre-certification) and simulations advanced post-processings of experimental and simulation data sensitivity studies, technical state of the art proposal of technical solutions and validation by tests or simulation Improve your design process performance • • • • development, validation and integration of high performance models development of user-specific design interfaces formalization of design rules delivery of high-level technical trainings Optimize your products and processes • • • coupling with multiobjective constrained optimization methods automation of the design process optimization of the “virtual prototyping” chain Innovate • • • technical state of the art, ideation, concept ranking and validation research consortium / co-development projects licence granting © EOMYS ENGINEERING 2014-2015 4 MANATEE software • • • • • • fast electromagnetic and vibro-acoustic simulation of electrical machines (Matlab-based) use of analytical, semi analytical and numerical models to reach the best compromise accuracy / speed automated coupling with FEMM (electromagnetic) and GetDP (mechanics) modeling of all space and time harmonics fault simulation (e.g. eccentricity, broken bar, demagnetization) more than 100 post processing graphs … see more at www.eomys.com © EOMYS ENGINEERING 2014-2015 EOMYS ENGINEERING – 121, rue de Chanzy 59260 Lille-Hellemmes FRANCE 5 Experience Optimal design of innovative systems permanent magnet synchronous wind generators, traction induction machines transformers and inductors Scientific software development use of open sources (FEMM, GetDP, OpenFoam, Octave) & commercial software (Flux, Opera, Ansys, Matlab) advanced optimization methods (multiobjective constrained genetic algorithms, space-mapping) development and distribution of MANATEE® software Analytical, semi-analytical and numerical modelling CFD simulation coupled to thermal nodal networks, hydraulic networks electromagnetic subdomain models, reluctance network models structural beam element models Experimental characterization noise and vibration measurements thermal and electrical measurements © EOMYS ENGINEERING 2014-2015 6 Internal R&D programme Reduction of noise & vibration in electrotechnical systems active and passive techniques in rotating electrical machines and passive components 3D electro-vibro-acoustic simulation of rotating machines (asymmetries, skewing) modeling of magnetic forces in rotating machines magnetostriction and Maxwell force simulation (GetDP) development of hybrid simulation methods (FEM / semi-analytic) Experimental vibroacoustic characterization advanced post processings new measuring methods of structural modes and operational deflection shapes © EOMYS ENGINEERING 2014-2015 EOMYS ENGINEERING – 121, rue de Chanzy 59260 Lille-Hellemmes FRANCE 7 B. WHY DEWESOFT ? • A “multiphysic” acquisition software suitable for multiphysics consulting activities of EOMYS (electrical engineering, thermics, vibro-acoustics, etc.) • A flexible software suitable for both investigation tests and pre-certification tests • An acquisition system suitable for both low frequency (ex: temperature) and high frequency (ex: noise) • A light-weight acquisition module suitable for field measurements • A cost-competitive solution © EOMYS ENGINEERING 2014-2015 8 C. MAGNETIC NOISE AND VIBRATIONS IN ELECTRICAL MACHINES What do we call “electromagnetic acoustic noise” or electrical noise ? • Sinusoidally-fed squirrel cage induction machine during run-up (« slotting noise ») • Non-sinusoidally-fed squirrel cage induction machine at starting (« PWM noise ») -> « high » frequency (100 to 10000 Hz), high tonality noise Definition • Magnetic noise and vibrations is defined as noise and vibrations due to magnetic forces • Magnetic forces can be defined as « forces arising from the presence of a magnetic field » -> magnetic noise stops when an induction machine is current-free • Two magnetic forces exist in electrical machines: magnetostriction & Maxwell forces © EOMYS ENGINEERING 2014-2015 9 Magnetostriction forces tend to « shrink » the iron along the field lines Maxwell forces tend to get the stator closer to the rotor STATOR yoke ROTOR slots teeth from [B7] © EOMYS ENGINEERING 2014-2015 10 Electrical noise and vibration phenomena electrical machine endplate mount • Tangential and radial magnetic force harmonics generate radial vibrations propagating to the external frame • Torque harmonics can propagate through rotor shaft as torsional vibrations, and efficiently radiated (large surface / normal vibrations) like gearbox frame or mount • Unbalance forces harmonics generate shaft bending vibrations which propagate to bearing & frame • Axial forces make endplates axial vibrations • Forced excitation + resonances gearbox frame shaft supports © EOMYS ENGINEERING 2014-2015 11 Why do electrical noise and vibrations matter ? • Health (e.g. in industry): lower the exposure to acoustic noise level • Comfort (e.g. in transportation): increase the sound “pleasantness” based on psychoacoustic metrics • Security (e.g. in defense): lower the vibroacoustic signature • Robustness (e.g. in energy): lower the electromechanical fatigue • Standard requirements Electromagnetics & vibroacoustics interactions • Cost optimization -> thinner yoker -> increased vibration & noise • Skewing technique which is used to reduce noise and vibration levels degrades torque and efficiency • Electromagnetic & thermal & vibro-acoustic design have therefore strong interactions © EOMYS ENGINEERING 2014-2015 12 Characterization of electrical noise and vibration • “time” frequency f • “space” frequency = space order = wavenumber r r=0 r=6 • harmonic origin: slotting, winding, PWM, saturation, eccentricity… • wave type: pulsating Vs rotating, rotation direction • forced excitation Vs resonance • largest magnetic force occurs at f=2fs (electrical frequency) r=2p (pole pair number) © EOMYS ENGINEERING 2014-2015 13 D. MEASUREMENT SETSET-UP • Dewetron SIRIUS 8 channel ACC+ • B&K 1-axis radial accelerometer in the middle of the stator stack (at least 8 recommended to capture r=4 order) • PCB ½ ’’ free field microphone 1 m away from the outer frame • Optel Thevon tachometer (1 pulse per rev) • Chauvin Arnoux current clamps ACTIVE © EOMYS ENGINEERING 2014-2015 14 E. ACQUISITION SETSET-UP Spectrograms • FFTs for noise (20 kHz), accelerometers (10 kHz) and current (5 kHz) Tachometer setup • Analog tacho Order tracking • For magnetic vibrations due to “slotting effects” the best orders to be tracked are 2p, Zr-2p, Zr, Zr+2p (p: number of pole pairs, Zr: number of rotor slots or number of rotor poles) -> some high rank orders are needed for high torque machines (ex: Zr=212) • For mechanical vibrations the order 1 should be also tracked • Specific set-ups are used for the best tradeoff between rpm and Hz accuracy © EOMYS ENGINEERING 2014-2015 15 © EOMYS ENGINEERING 2014-2015 16 Operation Deflection Shape Use of modal test environment of Dewesoft to visualize the stator deflection under magnetic forces • Calculation of reverberation time • Use of Dewesoft + Matlab to obtain the reverberation time in order to estimate the direct field (electrical machine) and indirect field (room reflections) contribution to the overall sound pressure level © EOMYS ENGINEERING 2014-2015 17 A-weighting and third octave analysis • dB and dBA as a function of speed Other tips = − 20 • Normalization of the noise level to the current level • Online estimation of slip in asynchronous machines using tracking filter • Current angle calculation based on 2 or 3 phase measurements • “Spatiograms”: 2D FFT run-ups of circumferential vibration waves © EOMYS ENGINEERING 2014-2015 ( ) =1− 60 18 F. EXPERIMENTAL RESULTS Operation deflection shape (case of a 1MW induction machine, r=1 & 2) © EOMYS ENGINEERING 2014-2015 19 Current spectrograms (IM, raw) fundamental © EOMYS ENGINEERING 2014-2015 slotting harmonic with dynamic rotor motion 20 Case of a concentrated winding PM synchronous machine (12 stator slots, 10 poles) • • run-up to 2200 rpm switching frequency at 1500 Hz 8 accelerometers © EOMYS ENGINEERING 2014-2015 21 Accelerometer spectrograms (raw) © EOMYS ENGINEERING 2014-2015 22 slotting excitations Accelerometer spectrograms (run(run-up) PWM +slotting excitations PWM excitations natural frequencies (vertical lines) © EOMYS ENGINEERING 2014-2015 23 Zoom on « slotting » excitations matching a mode close to 250 Hz © EOMYS ENGINEERING 2014-2015 24 Order tracking © EOMYS ENGINEERING 2014-2015 Wavenumber r=2 modulated by eccentricity 250 Hz natural frequency (parabola) 25 Spatiogram: Spatiogram: spectrogram of a specific space order r Complex value + dual side FFT © EOMYS ENGINEERING 2014-2015 26 r=2, f=2fs Spatiogram r=2 r=2p=10, f=-fswi -2fs same as r=-10, f=fswi +2fs r=2p=+10, f=fswi -2fs not available yet as a function of rpm… © EOMYS ENGINEERING 2014-2015 27 r=-2 and +2 spatiograms are the same (transposition) r=2 r=-2 © EOMYS ENGINEERING 2014-2015 28 r=0 r=2 © EOMYS ENGINEERING 2014-2015 29 Sidebands due to eccentricities Mechanical unbalance (rotation frequency) r=1 First bending mode r=2 © EOMYS ENGINEERING 2014-2015 30 r=3 r=2 © EOMYS ENGINEERING 2014-2015 31 r=4 r=2 © EOMYS ENGINEERING 2014-2015 32 • Plot / slot interactions appear as single sided-excitation (pure rotating force waves) • Eccentricities and PWM vibrations appear as double sided excitations (modulation effects: pairs of travelling vibration waves) • Natural frequencies appear as symmetrical amplifications in double sided FFTs • The machine vibration behavior is determined by wavenumbers 1 and 2 • “Spatiograms” based on Dewesoft Math functions are far more efficient than doing an ODS at each frequency and each speed… © EOMYS ENGINEERING 2014-2015 33 G. CONCLUSIONS • Advanced rotating machine analysis applied to electrical noise & vibrations reduction • On field post-processings allow to quickly identify the physical origin of noise & vibration • Combined with internal simulations (e.g. MANATEE software) some mechanical and electromagnetic redesign possibilities can be proposed and validated • Up to 15 dB reduction has been obtained after redesign © EOMYS ENGINEERING 2014-2015 34 Thank you for your attention Any questions? questions? www.eomys.com © EOMYS ENGINEERING 2014-2015 35