Annual Meeting and Technology Showcase Logan, Utah September 27-28, 2016 Power Electronics and Electric Drives Professor of ECE, Purdue University Dr. Steve Pekarek
Power Electronics and Electric Drives Fundamental building blocks of electrified transportation Research focused on: Converter topologies and control Wide bandgap devices (higher voltage and current levels) Integration of wide-bandwidth control (stability) Better passives Electric machine design and control Multi-objective optimization New materials New topologies
Power & Machines Faculty Introductions Dragan Maksimovic, CU-Boulder Bob Erickson, CU-Boulder Khurram Afridi, CU-Boulder Dionysios Aliprantis, Purdue Scott Sudhoff, Purdue Regan Zane, Utah State Zeljko Pantic, Utah State 10 posters and demos
Projects NASA - NRI PI: Sudhoff, Pekarek Design of electric machines for traction drives and humanoid robots Reduce mass and loss Navy Electric Ship Design PI: Pekarek, Sudhoff Design of Medium Voltage DC Systems Components, controls, stability Grounding, EMI/EMC 4
Projects John Deere: Control of IPM Drives with WBG Devices PI: Aliprantis, Pekarek DOE: A Disruptive Approach to Electric Vehicles Power Electronics PI: Bob Erickson, Dragan Maksimovic, Khuram Afridi Source Machine e as Ls R s Active Rectifier DC Bus Inverter Load Machine e bs L fs L dc R dc L f l R l L l e al L s R s L fs S1 S2 S3 S1 S2 S3 L f l R l L l e bl e cs L s R s L fs S4 S5 S6 S4 S5 S6 C dc1 C dc2 L f l R l L l e cl C wgs C wgs C wgs L dc R dc L b C wgl C wgl C wgl C gb S b D b L b Buck Converter R b DC Load C gb 5
Annual Meeting and Technology Showcase Logan, Utah September 27-28, 2016 A Disruptive Approach to Electric Vehicle Power Electronics Electrical, Computer and Energy Engineering University of Colorado Boulder Project supported by US DOE Vehicle Technologies Office PI: Prof. Robert Erickson Co-PIs: Prof. Dragan Maksimovic Prof. Khurram Afridi
Project Overview + V batt - Integrated Charger Composite DC-DC Converter + V bus - Inverter Motor 3φ-AC Goals: non-incremental improvements in Power density (2x) Average loss (4x) Film capacitor requirements (2x) Magnetics size (4x) Add-on volume of onboard level 2 charger An appropriate performance metric for loss-limited converter systems: Approach Fundamental improvements in converter circuit topology Compare performance of Si vs. SiC devices Optimization to minimize loss over standard drive cycles, based on calibrated converter loss models Integration of level 2 charger with DC-DC system
Modeling and design of drivetrain power electronics to minimize CAFE loss Design of power electronics system architecture and optimization of power component designs to minimize loss over standard drive cycles Low-power efficiency disproportionately impacts loss Drive cycle histograms
Boost Composite Converter Architecture Dissimilar partial-power converter modules: Same total silicon area as conventional boost approach Total film capacitor size reduced by 3x Significantly lower loss at high boost ratios Significantly reduced partialpower loss Dominant loss mechanisms are addressed: Use of pass-through modes to minimize AC losses Use of ultra-high-efficiency DC Transformer (DCX) module to convert most of the indirect power 1. H. Chen, K. Sabi, H. Kim, T. Harada, R. Erickson, and D. Maksimovic, A 98.7% Efficient Composite Converter Architecture with Application-Tailored Efficiency Characteristic, IEEE Transactions on Power Electronics, vol. 31, no. 1, pp. 101-110, Jan. 2016. 2. H. Chen, H. Kim, R. Erickson and D. Maksimovic, Electrified Automotive Powertrain Architecture Using Composite DC-DC Converters, IEEE Transactions on Power Electronics, 2016.
SiC Composite Boost Prototype 400 khz DCX switching frequency 200 khz buck and boost switching frequency Employs 900 V 10 mω SiC MOSFETs Planar magnetics use ELP43 and ELP64 ferrite cores Size of high density prototype Volumetric power density 23 kw/l Gravimetric power density 18.7 kw/kg Rated power 27 kw continuous, 39 kw peak for these SiC devices
Measured Si composite boost efficiency at 250 V : 650 V Ferrite planar transformer used in 60 kw prototype Calibrated loss models of SiC converter modules Loss model efficiency Measured efficiency 60 kw motor-generator set for testing EV drivetrain power electronics
Efficiency comparison (250-to-650 V, 15 kw) Si MOSFET composite SiC MOSFET composite SiC boost Si IGBT boost
Summary of converter technologies: EV drivetrain boost Converter Si-IGBT Conventional boost Si-MOSFET Composite boost SiC-MOSFET Conventional boost SiC-MOSFET Composite boost Switching frequency 10 khz 20 khz 240 khz 240 khz CAFE efficiency 94.3 % 98.2 % 96.9 % 98.3 % CAFE Q factor 22.2 55.3 34.7 58.6 Magnetic volume [relative to Si IGBT] Film capacitor size [relative to Si IGBT] 100% 108% 40% 24% 100% 30% 100% 30% Brute-force device replacement of Si with SiC in the conventional boost converter yields relatively small improvements in efficiency and converter Q Capacitor size is driven by rms current, and is unaffected by increase of switching frequency or use of SiC devices Composite architecture + SiC devices = transformative improvement Composite architecture addresses fundamental loss mechanisms SiC enables increased switching frequency and much reduced magnetics size In the composite architecture, SiC yields very high peak and average efficiency, much higher converter Q, and very high power density
Integrated SiC Charger Re-use of composite dc-dc boost modules SiC prototype, 6 kw 900 V 10 mω devices 120 khz switching frequency Planar magnetics 120 Hz energy storage capacitor plus 240 VAC interface module
SiC Inverter 10 khz, 800 V DC bus Same module used with Si composite boost and SiC composite boost systems Each phase employs SiC 1200 V 25 mω MOSFETs Rated power: 30 kw, power density: 16 kw/l Comparison with Si IGBTs, based on calibrated loss models: 1200 V Si IGBT 1200 V SiC MOSFET Semiconductor area 3464 mm 2 1801 mm 2 Rated current, per phase 360 A 360 A UDDS avg effcy/q 97.3%/35.8 99.0%/101 HWFET avg effcy/q 99.0%/96.1 99.5%/195 US06 avg effcy/q 98.3%/58.9 99.5%/199
Annual Meeting and Technology Showcase Logan, Utah September 27-28, 2016 Research Related to Electrified Vehicles Scott D. Sudhoff Michael and Katherine Birck Professor of Elect. and Comp. Engineering School of Electrical and Computer Engineering Purdue University Editor-in-Chief, IEEE Power and Energy Technology Systems Journal sudhoff@purdue.edu 765-494-3246 Wang 2057 465 Northwestern Avenue West Lafayette, IN 47907
Steel Characterization and Hi-Si Fe 3 10-3 -i Characteristic 2 1 f eq T 2 2 db = 2 2 B π dt 0 dt s, Vs 0-1 -2 Measured Estimated Anhysteretic αn 1 βn N T 2 feq B max ke f db h, n 2 n= 1 fb Bb B b dt 0 pld = k f + dt Hysteresis Loss Eddy Current Loss Fitted Anhysteretic -3-60 -40-20 0 20 40 60 i p, A 17
Analyticalish (Non-FEA) Magnetic Analysis Backiron Flux Density Tooth Flux Density 18
Analyticalish (Non-FEA) Structural Analysis FEA Model Relative error Inner bridge 18.99 MPa 19.51 MPa 2.75 % Outer bridge 15.85 MPa 15.47 MPa -2.39 % 19
Rotationally Asymmetrical Machines Rotor Speed (rpm) TABLE 6 AS-PMSM Design Model and FEA Torque Design 3-D FEA Model Torque (Nm) Torque (Nm) % Error 1000 rpm 18.0 17.6 2.20 2236 rpm 8.10 7.70 5.00 5000 rpm 3.70 3.40 8.10 20
Multi-PM-Pole Machines 21
Passive Component Design AC Inductors PM Inductors Common Mode Inductors LF Transformers HF Transformers http://www.nrel.gov/images/site_hpphoto_pv.jpg 22
Metamodel-Based Sub-System Design n (, ) KP (, ) KM * *1/3 M M pk M M k k= 1 M = c E J E + b 2 *1/3 *1/3 dc = P J M pk M + P k k= 1 P c K E J E b Mk, n, Pk,. 23
Metamodel-Based System Design 24
Power Electronics and Electric Drive Panelists Dr. Robert Erickson, Carline and Wilfred Slade Professor, University of Colorado-Boulder Dr. Scott Sudhoff, Michael and Katherine Birck Professor of Electrical and Computer Engineering, Purdue University Dr. Tao Wang, Engineering Manager, Control Electronics (Hybrid Vehicles), General Motors