Ele lectric M Machi hine ne S Simu mula lation T n Techno hnolo logy y Steve H Hartridge Di Director, E , Ele lectric & & H Hyb ybrid V Vehi hicle les
Agend nda � Int Introduction n � Todays ys d dema mand nds/Motivations ns � EMAG a G and nd T The herma mal mo l modeli ling ng � Comb mbine ned w workf kflo low E Example les
Motivation f n for A Ana nalys lysis � Over t the he la last d decade i it i is no noticeable le t tha hat t the here i is a a g growing ng ne need f for e ele lectric ma machi hine nes w with h High t h torque o or • High p h power d dens nsity a y alo long ng w with a h a • High e h efficienc ncy d y dema mand nd o or/and nd • Reduction i n in s n size, w , weight ht, c , cost • Leading ng t to hi highe her t temperature g gradient nts w with a h a hi highe her • dema mand nd o on t n the he ma materials ls i in g n gene neral, b l, but e esp. . on t n the he i ins nsula lation ma n materials ls : NREL Source g graphi hics: N sho horter li lifetime me e expectation d n due t to a a hi highe her • risk o k of t the herma mal d l dama mages ( (esp. i . in t n the he i ins nsula lation n ma materials ls). . A hi highe her r risk o k of d dema magne netization o n of t the he • ma magne nets
Motivation f n for A Ana nalys lysis � Component lifetime estimates [1]: – 22% of failures due to thermal damages in insulation – 17% further thermal damage in other components � Lifetime me d depend nds o on t n temperature hi history; y; Temperature d depend nds o on lo n losses a and nd c cooli ling ng � Insulation lifetime L can be modeled by the Arrhenius chemical equation [2]: L ¡ L ¡= ¡ ¡A · · 𝒇 𝒇↑ ( 𝒃/𝒄 ¡⋅ 𝒃/𝒄 ¡⋅ ¡ 𝑼 ) Montsinger’s rule taken from transformer oil and solid insulation materials shows � that the lifetime L decreases by 50% with increase of temperature T by 10 K [3]: L ¡ ¡(T (T ¡ ¡+ ¡ ¡10K) ¡ ) ¡= ¡ ¡0.5 ¡ ¡ ¡ ¡ ∙ ¡ ¡ L(T (T) So insulation breakdown is likely to be the problem associated with high temperatures. This problem may be tackled by – either improving the insulation material and allowing the temperatures to rise or – improving the cooling performance of the windings and limiting the maximum temperature. Source: [1] Bruetsch, R., Tari, M. Froehlich, K. Weiers, T. and Vogesang, R., 2008. Insulation Failure Mechanisms of Power Generators IEEE, Electrical Insulation Magazine, 24(4) [2] Dakin, T.W., 1948, Electrical Insulation Deterioration Treated as a Chemical Rate Phenomena, AIEE Trans., Part 1, 67 [3] Binder, A., TU Darmstadt, EW, 2008, Script Large Generators & High Power Drives
Motivation f n for A Ana nalys lysis � To accomplish today’s demand the new machine designs have – to eliminate the safety factors of the over-sizing designs of the past – to finally ensure the requested high power densities. � The need to have an optimized thermal design besides an optimized electro- magnetic design.
Ele lectric M Machi hine ne S Simu mula lation T n Techno hnolo logy y � Ele lectroma magne netic S Simu mula lation n � The herma mal S l Simu mula lation n • Ele lectrical/ l/me mecha hani nical p l performa manc nce o of • Und nderstand nd t the he e efficienc ncy o y of t the he c cooli ling ng design n sys ystem m • Design s De n studies o of d different nt t typ ypes o of • Optimi mize a a f flo low p paths hs f for a a g given c n cooli ling ng machi ma hine ne IM IMD v D vs. B . BDC DC sys ystem m • Torque a and nd e efficienc ncy r y requireme ment nts a are • Predict ma maximu mum c m compone nent nt met me temperatures a at g given d n different nt o operating ng point nts • Build ld e efficienc ncy ma y map f for ma machi hine ne • Cons nsider C Cond nduction/ n/convection/ n/ • De Detaile led g geome metric d design o n of radiation s n sys ystem m compone nent nts – – 2 2D/ D/3D D • Inc Inclu lude t temperature d depend ndent nt • Optimi mize ma magne net p position/ n/sha hape/ pr prope pertie ies s ma material l • Inclu Inc lude a a s simple le/cond nduction o n only nly Coupled the herma mal mo l model l Problem Machine Designer/ Thermal analyst/ Electrical Engineer Mechanical engineer
Losses i in E n Ele lectrical M l Machi hine nes � The heat generated inside the motor originates from two main sources: – Electrical losses include • the he c copper lo losses - a - als lso I 2 2 · R lo losses - i - in t n the he w wind nding ngs (he ( heating ng e effect d due t to c copper r resistanc nce), , • core lo losses a and nd ( (ma magne netic h hys ysteresis ( ( ~ B k · f ) a and nd e eddy c y current nts ( ( ~ B 2 · f 2 ) i in i n iron c n cores) • eddy c y current nt lo losses i in o n othe her p parts o of t the he ma machi hine ne b being ng e ele lectric cond nductive, , e.g .g p perma mane nent nt ma magne nets, e , end nd s shi hield lds, ho , housing ng p parts, … , … – Mechanical losses, such as • frictiona nal lo l losses g gene nerated b by t y the he b bearing ngs a as w well a ll as • wind ndage lo losses
The herma mal M l Modeli ling ng i in E n Ele lectrical M l Machi hine nes � Brushle hless g gene nerator Conjugate Heat Transfer Analysis of Integrated Brushless Generators for More Electric Engines Marco Tosetti, Paolo Maggiore, Andrea Cavagnino, Senior Member IEEE , and Silvio Vaschetto, Member IEEE Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino – Italy
The herma mal M l Modeli ling ng i in E n Ele lectrical M l Machi hine nes � Brushle hless g gene nerator Winding Temperature Stator Core Temperature Conjugate Heat Transfer Analysis of Integrated Brushless Generators for More Electric Engines Marco Tosetti, Paolo Maggiore, Andrea Cavagnino, Senior Member IEEE , and Silvio Vaschetto, Member IEEE Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino – Italy
Achi hieving ng C Couple led M Models ls � Ele lectroma magne netic S Simu mula lation n � The herma mal S l Simu mula lation n Coupled • Manu nual T l Trans nsfer o of lo losses • Templa late b based d design c n codes Problem • Rotor, Stator, Windings • Simple circuit models • Homogeneous application • Mapping of distributed losses • Finite Volume flow/thermal codes • Segmented by parts • Homogeneous losses on bodies • Maintain distribution of losses • Rotor • Typically from Finite element codes • Stator Codes often use a temperature • • Windings • Heterogeneous losses • Map between grids
Losses i in E n Ele lectric M Machi hine nes � Brushle hless DC DC mo motor, 1 , 10KW ma max p power � Homogeneous application of losses per component – Copper losses = 43 W – Iron losses stator = 345 W – Magnet losses = 0.74 W � Heterogeneous application of losses – See image � Comparison of Solution Heterogeneous Homogeneous
Losses i in E n Ele lectric M Machi hine nes � Comparison of maximum temperature Heterogeneous Homogeneous � Heterogeneous “mapped” losses lead to higher maximum temperatures
Data T Da Trans nsfer t to S STAR-C -CCM+ - - Losses Losses � The he B B-f -field ld v variation a n allo llows i iron lo n loss estima mation n – GoFER of 72 rotor positions /elec. revolution – Modified Steinmetz method in SPEED applies also to non sinusoidal currents � Front nt p part o of t the he t tooth s h sees s strong nger f field ld variations ns w whi hich i h is r refle lected i in t n the he hi highe her iron lo n loss d dens nsity y � The he i iron lo n loss d dens nsity c y can b n be v visuali lized SPEED D – Select the “Plot” Tab 13 13
Da Data T Trans nsfer t to S STAR-C -CCM+ - Ge - Geome metry y � SPEED g D geome metry f y for: s : stator, s , slo lot w wind nding ngs, , rotor, r , rotor b bars. � CAD g D geome metry f y for: e : end nd-w -wind nding ngs, e , end nd- ring ngs, a , all no ll non-a n-active c compone nent nts ( (fan, n, ho housing ng, e , etc…)
SPEED > D > S STAR-C -CCM+ Ind Industrial E l Example le � Ind Induction ma n machi hine ne, o , overblo lown w n with f h fan o n on t n the he s sha haft – SPEED Model > loss distribution – STAR-CCM+ > Temperature profiles
Simu mula lation S n Steady S y State T Temperatures 2 1 2 1 • Rotor B Bar Av Avg=148.4 .4 C C, E , End nd R Ring ng 1 1 Av Avg=144.7 .7 C C, E , End nd R Ring ng 2 2 Av Avg=147.6 .6 C C • Sha haft M Min T n Temp=55.8 .8 C C, S , Sha haft M Max T Temp=148.3 .3 C C • SPEED mo D model w l with r h rotor t temp @ @ 1 148 C C r requires 5 52.5 .5 % % o of c copper cond nductivity f y for c cons nsistent nt lo losses a and nd p performa manc nce a at t thi his lo load p point nt. . 16 16
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