model based design of hybrid and electric powertrains
DESCRIPTION
Hybrid and Electric Drives are far more complex than the traditional I.C. Engine based powertrains of cars and trucks. Such complexity multiplies the possible failure modes that could lead to catastrophic failure of the drivetrain, as well as make the job of optimizing the powertrain for fuel efficiency, much more challenging. Model Based Design is a solution to manage complexity, find and eliminate failure modes, and to find and exploit even obscure performance improvement opportunities. This presentation shows some nuances and advances of Model Based Design methods for Hybrid and Electric PowertrainsTRANSCRIPT
MODEL BASED DESIGN OF
HYBRID AND ELECTRIC POWERTRAINS
Sandeep Sovani, Ph.D.
ANSYS Inc.
October 22, 2013
SAE 2013 Hybrid Powertrain Complexity
And Maintainability Symposium
Acknowledgements:
Scott Stanton, Todd McDevitt, Eric Bantegnie,
Xiao Hu, ANSYS Inc.
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As mechanical, electrical, electronic and software systems in a vehicle are
getting ever more tightly integrated, three key necessities are arising
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Mechanical/Fluid
Electrical & Electronics
Software
Mechanical/Fluid Software
Electrical & Electronics
Mechatronics
Manage Complexity
to design innovative, market leading products
Early & Reliable Verification
to deliver high quality products to the market
faster
Coordinate Interdisciplinary
Engineering
to reduce design changes and development costs
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The hybrid electric powertrain is the most complex vehicle system
involving diverse interdisciplinary engineering
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Predicting the behavior of a Hybrid Electric Powertrain over a drive cycle requires simulation of multiple domains: • Mechanical, Hardware • Electrical, Electronics • Software
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Simulating the electric powertrain as a complete, interconnected system is
particularly challenging due to fragmentation of simulation tools and
methods at different stages of the product development process
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System Validation
Sub-System Integ. & Verification
Component Integration & Verification
Requirements and Specifications
Component Design
System Functional & Architectural Design
Mechanical Electrical Software
Customer Requirements: Adjust the speed of my vehicle to keep it at a safe distance behind the lead vehicle even in fog or heavy rain
Functional Specification: The car must adjust its speed without users control
Alt. A: Preview Distance Control System
Alt. B Radar Cruise Control System
Alt. C Dynamic Laser Cruise Control System
System Simulation Testing
Components Testing
Requirements Capture and Management
Product Structure
Optimal Architecture
Mechanical Electrical Software
System Models
Systems Simulation
Detailed Design & Optimization
Release Product
Manage Complexity
Coordinate Interdisciplinary
Engineering
Early & Reliable Verification
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Systems functional engineering tools, software engineering tools, and
detailed 3D design tools need to be seamlessly integrated to create an
effective tool for handling the complexity of hybrid electric powertrains
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System Validation
Sub-System Integ. & Verification
Component Integration
& Verification
Requirements and Specifications
Component Design
System Functional & Architectural Design
Mechanical Electrical Software
Detailed Design & Optimization
Systems Functional Engineering
Functional Allocations
Detailed Architecture Architecture
Software Engineering
Detailed 3D Design and Simulation
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A multi-fidelity simulation toolset is essential to most effectively meet the
different design needs at different stages of the product development
process
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Model Simulation Result
Requirement Req 23: On request, the valve should close in 500us
X
Functional simulation
System simulation (0D)
High fidelity simulation
(3D) - Open loop validation
System Validation
(0D-ROM-Ctrl)- Close loop validation
500us 0
Pos
true
false t
0
500us
t
Pos
Pmax
Actuator
t
Pos
0 500us
t
Pos
Pmax
500us
Pmax
Pmax
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We are testing a comprehensive simulation platform comprised of in-depth
integrated tools to full system simulation of the hybrid electric powertrain
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System Design
System Architecture, System Verification Detailed
Component Design
3D Simulations for Fluids, Thermal, Mechanical, Electrical, Magnetic
Effects System & Software
Lifecycle Mgmt Certification Plans, Metrics,
Requirements, Configuration Management,
Documentation Generation
Circuit Design and Control
Software Design Prototyping, Design,
Verification, Qualified Code Generation
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Requirements Mgmt and
Functional Design
Practices
Requirements analysis
Requirements traceability
Configuration management
Operational and usage analysis
Functional decomposition
Functional simulation
Architectural design & selection
Rapid prototyping
Behavior modeling (0D simulation)
At the highest level system design starts with requirements analysis,
operational and usage analysis, functional decomposition, architectural
design and basic behavioral modeling
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At the component design and verification level a data connector bus and
0D simulator forms the central core of the simulation platform
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The second key element at the component design and verification level is a
comprehensive control software development tool set that prototypes and
designs software models, verifies them, and generates certified code
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At the detailed component design level, 3D simulation tools help develop
and optimize the components from fluid, thermal, structural, electrical,
magnetic, acoustic, etc aspects
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Fluid, Thermal Simulation of a Battery Module
Pre-Stressed Structural Modal
Analysis of a Motor
Electrical Current and Heating Simulation of
an IGBT
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Example 1:
Integrated power electronics and embedded controls development
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Example 1 . . . Continued
An incremental approach is used to design the system
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Example 1 . . . Continued
At level 1, open loop electric behavior is studied
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Example 1 . . . Continued
At level 1, system validation includes switching commands from embedded
code
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Switching commands coming from the Embedded Code
Angle and Torque on the load
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Example 1 . . . Continued
At level 4, closed loop control and detailed electric analysis is performed
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Example 1 . . . Continued
At level 4 system validation considers switching commands from
embedded code as well as feedback commands
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Switching commands coming from the Embedded Code and feedback command
Angle and Torque on the load
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Example 2 . . . Continued
Hierarchical IGBT models suite different purposes: A dynamic IGBT model
is necessary for EMI analysis
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DC core
A
Energy calculation
B
Thermal network
F
DC core
A C
Thermal network
F
Capacities C(V), C(I)parasitics L, R, Ccontrolled sources
E
Full parameter excess
Maximum simulation speed:
• Accurate static behavior
• Accurate thermal response
• No voltage and current transients
• Suitable for system design analysis
Average IGBT Model Dynamic IGBT Model
Maximum simulation accuracy:
• Sophisticated semiconductor model
• Accurate dynamic and thermal behavior
• Accurate voltage and current waveforms
• Suitable for drive optimization, EMI/EMC
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Example 2 . . . Continued
Dynamic IGBT model accurately captures switching waveforms
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Static IGBT for fast system simulations
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Example 2 . . . Continued
Detailed 3D thermal and electrical analysis of the IGBT further improves
waveform accuracy
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EMI/EMC: Automatic L,R,C Extraction and Network Model
The structure is meshed using automatic and adaptive meshing
Current Distribution
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Example 2 . . . Continued
The IGBT model couples seamlessly with detailed motor model to optimize
the sub-system in an integrated way
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-22.50
60.00
0
25.00
50.00
0 240.00m100.00m
2DGraphSel1 NIGBT71.IC
Extract Power Loss
0
474.00m
200.00m
400.00m
100.00 1.00Meg1.00k 3.00k 10.00k 100.00k
2DGraphCon1
GS_I...FFT
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The battery pack is hierarchically simulated from the smallest electrode level scale
to the largest pack level scale and a behavioral model of the pack is extracted that
fits in the powertrain system level simulation
Example 3
Total battery simulation
Electrode Level
•Electrode layout •Heat source calculation •Aging
Molecular Level
•Material innovation •Material selection
Cell Level •Charging, dischar-ging profiles •Cell level heat distribution •Swelling, deformation
Pack Level •BMS Logic •Electrical System •Cooling Channels •Cooling Circuits
Powertrain and Vehicle Level
•System Integration
Smal
l Sca
le
Larg
e S
cale
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Example 3 . . . Continued
Electrochemistry at the cell electrode level is simulated with 1D and 3D
models
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Impact of Temperature on Concentration Distribution
Impact of Particle Shape on Capacity
Rate 0.1C 0.5C 1C 3C 5C 10C
Validation of Reduced Order Electrochemistry
[1] X. Hu, S. Stanton, L. Cai, R.E. White, J. Power Sources 214, 40-50, 2012. [2] X. Hu, S. Stanton, L. Cai, R.E. White, J. Power Sources 218, 212-220, 2012.
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Example 3 . . . Continued
Cell electrical behavior is characterized by simulating electrical, flow and
temperature distributions in the cell in detail
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Current Density Cathode Anode
J
)( UYJ ac
Temperature
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Example 3 . . . Continued
Cell Equivalent Circuit Models are developed that account for detailed
thermal and electrical effects and are integrated into a module model
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X. Hu, L. Collins, S. Stanton, S. Jiang, "A Model Parameter Identification Method for Battery Applications", SAE 2013-01-1529.
Battery Pack ECM Model
Simulation Results
Cell Equivalent Circuit
Model (ECM)
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State space based Linear Time Invariant Model
Example 3 . . . Continued
Module level detailed cooling models are developed and reduced to a
thermal reduced order model (ROM) which augments the ECM
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ROM for the Battery Module
LTI
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Example 3 . . . Continued
Busbars are characterized with thermal, structural and electric simulation
and all components are integrated to create the pack model
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Electromagnetic FEA Analysis for Busbar RLC Network Extraction
Voc vs. SOC
Pulse Discharge
Battery Equivalent Circuit Model (ECM)
Battery Performance Data
Pack Level Battery ECM
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Summary:
Hierarchical multi-domain, multi-fidelity simulation provides the ability to
perform early and reliable verification while managing complexity, of
interdisciplinary H/EV powertrain engineering
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Mechanical/Fluid Software
Electrical & Electronics
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System Validation
Sub-System Integ. & Verification
Component Integration & Verification
Requirements and Specifications
Component Design
System Functional & Architectural Design
Detailed Design & Optimization
