Annual Meeting and Technology Showcase – Logan, Utah – September 27-28, 2016
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 Electronics and Electric Drives
• 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
Power & Machines Faculty Introductions
ProjectsNASA - NRIPI: Sudhoff, Pekarek• Design of electric
machines for traction drives and humanoid robots
• Reduce mass and loss
Navy Electric Ship DesignPI: Pekarek, Sudhoff• Design of Medium
Voltage DC Systems– Components, controls,
stability– Grounding, EMI/EMC
4
ProjectsJohn Deere: Control of IPM Drives with WBG DevicesPI: Aliprantis, Pekarek
DOE: A Disruptive Approach to Electric Vehicles Power Electronics PI: Bob Erickson, DraganMaksimovic, Khuram Afridi
5
Source Machineeas Ls Rs
ebs
ecs
Lfs
Ldc Rdc
eal
ebl
ecl
S1 S2 S3
Ldc Rdc
Ls Rs Lfs
Ls Rs LfsS4 S5 S6
Cwgs
LlRlLf l
LlRlLf l
LlRlLf l
Cwgl
DC Bus
Cdc1 Cdc2
Active Rectifier Inverter Load Machine
Rb
Lb
Lb
Cgb
Cgb
Db
Sb
Buck Converter DC Load
Cwgs Cwgs Cwgl Cwgl
S1 S2 S3
S4 S5 S6
Annual Meeting and Technology Showcase – Logan, Utah – September 27-28, 2016
Project supported by US DOEVehicle Technologies OfficePI: Prof. Robert EricksonCo-PIs: Prof. Dragan Maksimovic
Prof. Khurram Afridi
A Disruptive Approach to Electric Vehicle Power Electronics Electrical, Computer and Energy Engineering
University of Colorado Boulder
Project Overview Composite
DC-DCConverter
InverterMotor
VbusVbatt
+
-
+
-
Integrated Charger
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
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
An appropriate performance metric for loss-limited converter systems:
Modeling and design of drivetrain power electronics to minimize CAFE loss
Drive cycle histograms• 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
Boost Composite Converter ArchitectureDissimilar 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 partial-power 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 power1. 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 coresSize 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
60 kW motor-generator set for testing EV drivetrain power electronics
Measured Si composite boost efficiencyat 250 V : 650 V Ferrite planar transformer used in 60 kW
prototype
Loss model efficiencyMeasured efficiency•
Calibrated loss models of SiC converter modules
Efficiency comparison (250-to-650 V, 15 kW)
SiCboost
Si IGBT boost
Si MOSFET composite
SiC MOSFET composite
Summary of converter technologies: EV drivetrain boost
• 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
Converter Si-IGBTConventional boost
Si-MOSFETComposite boost
SiC-MOSFETConventional boost
SiC-MOSFETComposite 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] 100% 108% 40% 24%
Film capacitor size [relative to Si IGBT] 100% 30% 100% 30%
Integrated SiC Charger
Re-use of composite dc-dc boost modules
120 Hz energy storage capacitor
plus 240 VAC interface module
SiC prototype, 6 kW• 900 V 10 mΩ devices• 120 kHz switching frequency• Planar magnetics
• 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:
SiC Inverter
1200 V Si IGBT 1200 V SiC MOSFET
Semiconductor area 3464 mm2 1801 mm2
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
Scott D. SudhoffMichael and Katherine Birck Professor of Elect. and Comp. EngineeringSchool of Electrical and Computer Engineering | Purdue UniversityEditor-in-Chief, IEEE Power and Energy Technology Systems Journal
[email protected] | 765-494-3246 | Wang 2057 465 Northwestern Avenue | West Lafayette, IN 47907
Research Related to Electrified Vehicles
Steel Characterization and Hi-Si Fe
17
-60 -40 -20 0 20 40 60
ip
, A
-3
-2
-1
0
1
2
3
s, V
s
10 -3 -i Characteristic
Measured
Estimated Anhysteretic
Fitted Anhysteretic
2
2 20
1 2max
, 21 0
2
n n
T
eq
TNeq e
ld h nn b b b
Eddy Current LossHysteresis Loss
dBf dtB dt
f B k f dBp k f dtf B B dt
α β
π−
=
= ∆
= +
∫
∑ ∫
Analyticalish (Non-FEA) Magnetic Analysis
18
Tooth Flux Density
Backiron Flux Density
19
Analyticalish (Non-FEA) Structural Analysis
FEA Model Relative errorInner bridge 18.99 MPa 19.51 MPa 2.75 %Outer bridge 15.85 MPa 15.47 MPa -2.39 %
Rotationally Asymmetrical Machines
20
TABLE 6 AS-PMSM Design Model and FEA Torque
Rotor Speed (rpm)
Design Model
Torque (Nm)
3-D FEA 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
Multi-PM-Pole Machines
21
Passive Component Design
22
AC InductorsPM InductorsCommon Mode InductorsLF TransformersHF Transformers
http://www.nrel.gov/images/site_hpphoto_pv.jpg
Metamodel-Based Sub-System Design
23
( ) ,* *1/3,
1,
M M kK n
M M pk M M kk
M c E J E b=
= +∏
( ) ,2 *1/3 *1/3,
1.
P P kK n
dc P J M pk M P kk
P c K E J E b=
= +∏
Metamodel-Based System Design
24
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
Power Electronics and Electric Drive