Smart System Solutions for the Drive- Train of Commercial Electric Vehicles

Transcription

1 EPSS Annual Frum 2014 Turin, Italy Sept. 25, 2014 Smart System Slutins fr the Drive- Train f Cmmercial Electric Vehicles Sven Rzepka 1, Alexander Ott 1, Flrian Hilbert 2, Dag Anderssn 3 1,, Technlgie-Campus 3, D Chemnitz, Germany 2 Fraunhfer IISB, Drives and Mechatrnics, Schttkystr. 10, D Erlangen, Germany 3 Swerea IVF, Argngatan 30, SE Mölndal, Sweden Page 1 Head: Prf. Dr. Sven Rzepka

2 I. Intrductin Prject duratin: Oct'12 Sep'15 COSIVU Prject: Develpment f a nvel electric drivetrain system architecture by realizing a smart, cmpact, and durable singlewheel drive unit including: integrated electric mtr 2-stage gear system inverter with SiC based pwer electrnics nvel cntrl and health-mnitring system with wireless cmmunicatin advanced ultra-cmpact cling slutin Validatin platfrm: cmmercial vehicle (VOLVO) + passenger car (Elaphe) Page 2 ENAS + IISB

3 II. System architecture Overview Mechanically self-supprting structure, Reduced cable harness Direct bard-t-bard cnnectin between Drivers & Inverter Cntrller Mdule Inverter E-Mtr Inverter Building Blck Cmplete half-bridge t drive ne phase leg f the electric machine: Page 3

4 II. System architecture SiC BJT pwer mdule Pwer mdule in half-bridge cnfiguratin with full SiC cmpnents: 4x SiC biplar junctin transistrs (BJT) frm FCS 4x SiC dides frm Cree 1200V, 50A (dide: 54A) Substrate: DCB with aluminum nitride (AIN) as ceramic islatr Lead-free slder; Alu wirebnds (E: 300µm, B: 150µm) Encapsulatin: epxy mld cmpund (EMC) FCS SiC pwer mdule: Schematic f pwer mdule: (half bridge cnfiguratin, 3 PMS in parallel will frm tgether 1 f the 3 phase legs f the inverter) SiC biplar junctin transistr: Page 4

5 II. System architecture Nvel cling cncepts 2 COOL Investigatin f new duble-sided cling cncepts t imprve current carrying capability (pwer density) with new SiC devices Remval f wire bnds will allw: Reduced switching lsses (significant reductin f switching cell inductance will allw higher switching frequencies) Increased reliability New cling structures are currently being investigated: Staggered pins Spnge structures Staggered Pins Spnge structure Page 5

6 II. System architecture Electric mtr Develpment f a new near-wheel highpwer density electric mtr fr passenger cars by Elaphe Integratin will be dne in a VW Sharan 4 Mtin New high-trque electric mtrs frm Elaphe: Perfrmance data: (withut FW) 20.9 (active) + up t 20 (passive with cling and cnnectins) Selected mtr efficiency map and perating regin: Page 6

7 Zth in K/W delta Zth in K/W II. System architecture Health mnitring functinalities Health mnitring f electric mtr + gear: By slid-brne sund measurements with piezelectric fils Health mnitring f il: By analyzing dynamic viscsity, cnductivity, density and dielectric prperties f the fluid with a small MEMS based tuning-frk element Health mnitring f pwer electrnics: By perfrming in-situ thermal impedance measurements n the pwer mdules 0,25 0,20 0,15 0,10 0,05 Change f Z th due t degradatin 0,00 1E-4 1E-3 1E-2 1E-1 1E+0 1E+1 time in s Zeit in s [1] [1] 0,045 Lcatin f degradatin Zthjkk_neu[] jh new Zthjkk_wlp[] jh thermal grease ZZthjkk_sys[] jh baseplate slder ZZthjkk_chip[] jh chip slder 0,040 0,035 0,030 0,025 0,020 0,015 0,010 0,005 0,000 Z th (t) changes in dependence f the lcatin where the degradatin happens -0,005 1E-4 1E-3 1E-2 1E-1 1E+0 1E+1 time in s Zeit in s Lcatin f degradatin ZChip-Neu th jh chip slder Z Sys-Neu th jh baseplate slder Z WLP-Neu th jh thermal grease Page 7

8 II. System architecture Wireless cmmunicatin Investigatin f different wireless cmmunicatin slutins t be used in harsh envirnment applicatins such as in electrical drive-train systems Data rate vs. range Usage f ISM-Bands 868/915 MHz (ZigBee, KNX-RF, Z-Wave, EnOcean) Only shrt pulses (Cntinues usage nt allwed) less lad n frequency band Better material diffusin / range 2400 MHz (BlueTth, ZigBee) Cntinues usage eg. IT netwrks high lad n frequency band Higher data transfer rate Page 8

9 III. Reliability Pwer cycling tests Pwer Cycling Lab : Temperature cntrllable sample hlders fr duble-sided cling during pwer cycling test have been develped (with ptimized temperature distributin) 8 single-sided Pwer Mdules (16 SiC BJT at ne time) are tested simultaneusly and cmpared with test results f new duble-sided cling versins Sample hlder design: DUT cnnectin plan: Page 9

10 III. Reliability FE simulatin: Gemetry mdel FE simulatin targets: Investigatin f mechanical stress cncentratin and accumulating plastic and creep strain induces by: Glbal mdel Mld cmpund Pin BJT Manufacturing prcess (sldering f DCB, transfer mlding) Internal and external thermal lads Replicatin f the crrespnding physical effects Simulatin mdel: Ralf Döring Leadframe Dide Nn destructive CT inspectin and pwer mdule determinatin f input fr 3D simulatin Page 10

11 III. Reliability FE simulatin: Gemetry mdel Lcal gemetry mdel f wire bnd: Psitin f lcal bnd wire mdel Psitin f bnd wire derived frm CT scan: 3D image f wire-bnds: Page 11

12 III. Reliability FE simulatin: Gemetry mdel Chesive zne apprach fr wire bnd: Gemetry infrmatin derived frm 3D digital micrscpe images Crack grwth law (Paris and Erdgan): Linear tractin-separatin respnse: Bnd wire base (200µm) Chesive zne area (1µm) Metallizatin (10µm) Die (380µm) Page 12

13 III. Reliability FE simulatin: Validatin Result validatin : Gd agreement between warpage measurement and simulatin Warpage measurement results: OMI Equinx: Simulatin results: Page 13

14 III. Reliability FE simulatin: Die Attach Reliability FE simulatin results: Quantifying f creep strains in the die attach f the SiC dies accumulated ver the prcess steps and thrugh thermal cycling already by glbal mdel Significant strains and stress can be bserved in the die attach Results indicate that creep strain are primarily influenced by the high CTE mismatch between DCB and SiC dies Accumulating equivalent creep strain (= failure criterin) in die attach may lead Simulatin: t slder Eberhard fatigue Kaulfersch Equivalent creep strains accumulated after ne thermal cycle (-40 C t 150 C) Page 14

15 III. Reliability FE simulatin: Bnd Wire Reliability FE simulatin results: Thermal cycle: -40 C +150 C Sub-mdeling Technique: Mechanical stress cncentratin and plastic defrmatin at the bnd wires (lcal mdel) Strain distributin & magnitude Reliability risk assessment (Failure mde: Wire bnd lift-ff) Simulatin: Eberhard Kaulfersch Page 15

16 IV. Summary & Outlk A new system architecture fr electric drive-train systems has been presented It includes a nvel cmpact SiC based inverter design, new high-pwer density electr mtr in case f passenger car and new sensr slutins fr healthmnitring functinalities (slid-brne sund sensr, il cnditin sensr, current sensr thermal impedance spectrscpy) as well as ptential wireless cmmunicatin slutins New integratin cncepts with duble-sided cling are currently under test Reliability f pwer electrnic is f particular cncern due t harsh envirnmental cnditins, high safety relevance and new SiC technlgy: New tests applying multiple lads simultaneusly have been develped Next steps: System integratin and testing - Test bench and vehicle level Reliability: Lifetime mdel fr pwer mdules (active + passive thermal cycles) Page 16

17 Thank Yu fr Yur attentin! Cntact: Prf. Dr. Sven Rzepka, Technlgie-Campus 3, Chemnitz Tel: +49 (371) / ~ Page 17