Using ADVISOR for Analysis of HEVs

Meisam Amiriamirim@ut.ac.ir

Outline

Needs for simulation toolsDemonstration of ADVISORBackground on ADVISORBackground on ADVISORCapabilities of ADVISORWorking Principles of ADVISORUsing ADVISORUsing ADVISOR

- Vehicle Templates- ADVISOR’s File System- Defining a vehicle- Running a simulation- Looking at outputs

Engines & Emission StructureUsing ADVISOR in an Optimization LoopLi ki t ADVISORLinking to ADVISOR

- ADAMS/ADVISOR Co-simulation

Simulation of a Hybrid Electric vehicleSimulation of a Hybrid Electric vehicleLimitations

Needs for simulation tools

Many configurations / energy management / control y g gy gstrategies

Analytical solution is difficultAnalytical solution is difficult

Prototyping and testing is expensive & time consumingconsuming

Optimization can be arduous task since there are lit ll h d d f t ff ti itliterally hundreds of parameters affecting its performance

Advisor Demonstration

Background on ADVISOR

ADVISOR = ADvanced VehIcle SimulatORsimulates conventional, electric, or hybrid vehicles (series, parallel, or fuel cell)

ADVISOR was created in 1994 to support DOE Hybrid Program at NREL

Released on vehicle systems analysis web site for free download in September, 1998

Downloaded by over 9000 people around world

Background on ADVISOR

Distributed on web by NREL from 1994-2002

In 2003, ADVISOR licensed to AVL for commercial release

Users help provide component data and validation, feedback for future developmentfeedback for future development

Programmed in MATLAB/Simulink environment

- graphical/object-oriented environment- allows flexibility in modeling new vehicles and

control strategiescontrol strategies

ADVISOR Being Used Globally

ADVISOR Downloads by Type of Organization

Capabilities of ADVISOR

Various vehicle typesC ti l S i h b id P ll l h b id d F l llConventional, Series hybrid, Parallel hybrid and Fuel cell

Various control strategiesThermostat Power follower Power assist etcThermostat, Power follower, Power assist, etc.

GUI or batch mode operationParametric studiesParametric studiesPerformance assessmentsTrade off studiesTrade-off studiesEvaluating new technologies

Capabilities of ADVISOR

ADVISOR will allow the user to answer questions like:Was the vehicle able to follow the speed trace?Was the vehicle able to follow the speed trace?How much fuel and/or electric energy were required in the attempt?How does the state-of-charge of the batteries fluctuate throughout a cycle?cycle?What were the peak powers delivered by the drivetrain components?What was the distribution of torques and speeds that the piston engine delivered?delivered?What was the average efficiency of the transmission?

Predicts fuel economy, emissions, accel. performance and grade sustainability and optimization

Working Principles

ADVISOR operates in the MATLAB/Simulink environmentMatlab is chosen for its programming ability modeling flexibilityMatlab is chosen for its programming ability, modeling flexibility, optimization toolbox and visualization tools

Vehicle data is provided in Matlab files (m files) and models p ( )are developed in Simulink (calculations)

Empirical model using drivetrain component performancesp g p p

Graphical User Interface (GUI), allows the user to model any type of ICE/EV/HEV by easily changing the vehicle a y type o C / / by eas y c a g g t e e c econfiguration and parameters without having to modify the Simulink block diagrams.

Working Principles

ADVISOR is a backward facing model with limited forwardfacing capabilities

In backward-facing calculations, no driver behavior isrequired. The user must input the driving pattern, a velocity profile, called the

d t Th f i d t l t th hi l i l l t d dspeed trace. The force required to accelerate the vehicle is calculated and translated into torque. This procedure is repeated at each stage from the vehicle/road interface through the transmission, drivetrain,etc., until the fuel use or energy use is calculateduse or energy use is calculated

In forward-facing calculations the user inputs the driverIn forward-facing calculations, the user inputs the driver model, then the simulator generates throttle and brake commands that are changed into engine torque, which is passed to the transmission model and passed through the drivetrain until a tractive force is computedpassed through the drivetrain until a tractive force is computed.

Principles Contd…

HEV model

Backward-facing model pass torque, speed, and power requirement up the drivetrain

F d f i d l il bl t dForward-facing model pass available torque, speed,force and power through the drivetrain

Represent model (data processing modules) contains allRepresent model (data processing modules) contains all data processing elements, such as “Sum” and “Product” blocks and look-up tables, necessary to model

ADVISOR Vehicle Templates

Conventional Vehicles

Series Hybrid VehiclesSeries Hybrid Vehicles

Parallel Hybrid Vehicles

ADVISOR’s File System

Three Main ADVISOR Screens

ADVISOR GUI (Defining a Vehicle)

2

1. User can select his ownvehicle configuration &components using drop 2components using drop-down menususer can modify variablesi th i bl li tin the variable listautosize: accel’n/gradeconstraints and optimizing

1

drivetrain components

2. Graphical representation

31of the powertrain selected

3. Shows the performancepinformation of the comp-onents (efficiency contours, emission contours and batteries

How the Data/Models are Pulled into the GUI

Example of ADVISOR Input: the FC model

GUI contd…

Basic Structure and Models

Engine Thermal Model

Multi node thermal networkParameterized for flexibilityIncludes conduction radiation and convectionIncludes conduction, radiation and convection

ADVISOR Engine Data Flow

GUI (Running a Simulation)

1. User can select a drive-cycle/test procedure nocycle/test procedure, no.of cycles etc.Declare initial conditionssoc correction for HEV

1

soc correction for HEV

2. Gradeability and accel’ni t

23requirements

parametric analysis canbe done

3

3. Views drive cycle selectedand associated statistics/descriptionp

Types of Simulation Tests Possible

Parametric SweepsDrive CyclesAcceleration TestGrade TestControl StrategyControl Strategy Optimizations

GUI (Looking at Outputs)

1. Shows the fuel econ.,li i l t d R l Sgasoline equivalent and

distance covered

2 Emission data6

Results Screen

2. Emission data

3. Accel’n and Gradeability 12

5

4. Warnings: if the trace isnot met or failed inperformance criteria

2

3performance criteria

5. Plot control 46. Graphs: max. 4 plots

ADVISOR Output

Average fuel economy and emissionsTime-dependent plots of variablesScatter plots: regions of operation within component maps

ADVISOR Output

Fuel economy, emissions, acceleration times, or achieved grade as a function of your chosen variables can be can be displayed

2 Variable Parametric Study

3 Variable Parametric Study

Engine and Emissions Model Structure

Temperature, Fuel & Emissions Calculation

ADVISOR Emissions Data Flow

Using ADVISOR in an Optimization Loop

Numerically OptimizationOptimization allows complex trade-offs to be performed numerically

Applying Optimization Technique

Example: Fuel cell hybrid SUVMaximize fuel economy of fuel cell hybrid SUVC fCoupling of sizing with control strategy leads to improve solution (56.5 mpgge, up from starting point of 41 mpgge)Multiple local optimums in HEV design spacep p g p

Complex design space of hybrid fuel cell vehicles has local optimum, and requires multi-algorithm approach to find global optimum

Control Strategy Comparison (engine power)

Control Strategy Comparison (battery power)

Linking to ADVISOR

NREL i ki ith i d t t li k ADVISORNREL is working with industry to link ADVISOR up to tools they use, such as:

Pro/E (visualization, packaging)Visual-Doc (Optimization)SABER ( l t i l)SABER (electrical)ADAMS/Car (vehicle dynamics)Flowmaster (detailed thermal modeling)

Interfacing ADVISOR and ADAMS/Car

Two interface approaches will be used:

ADAMS/ADVISOR Co-simulation

Export to ADAMS/CarEach approach has its own advantages and serves different simulation purposes.

ADAMS/ADVISOR Co-simulation

What?Linking ADAMS/Car full vehicle model with ADVISOR- Linking ADAMS/Car full vehicle model with ADVISORmodel

- Both ADAMS and Simulink solvers run togetherInformation passed back and forth between the two ateach time step

How?- ADAMS/Car full vehicle model using customized

powertrain template- Modified ADVISOR model to work with ADAMS/Car model- Modified ADVISOR model to work with ADAMS/Car model

ADAMS/ADVISOR Co-simulation

Why?

Simulate 4WD/AWD powertrains- Simulate 4WD/AWD powertrainstorque split can be actively controlled by ADVISOR

- Vehicle handling/dynamics with new CM from ADVISORl k bili i l i b lcan look at stability issues relating to battery placement

- Calculate energy losses during handling/durability eventsuseful for trying minimizing losses for maximum fuel efficiency

- Integrate accessory loads (like electric power steering) and lookat their energy impact vs. performance

- Trade-offs to accurately assess impact of vehicle/componentmass reduction and evaluating effect on dynamic performance

- Perform anything you would normally do in ADAMS/Car but- Perform anything you would normally do in ADAMS/Car, butusing an advanced powertrain from ADVISOR

ADAMS/ADVISOR Co-simulation

ADAMS/ADVISOR Co-simulation

Information FlowThe major variables exchanged are shown below AdditionalThe major variables exchanged are shown below. Additional information will also be exchanged.

Export to ADAMS/Car

What?- ADAMS/Car full vehicle model with mass and inertia

properties exported from ADVISOR

- One way information flow to ADAMS/Car

How?- Output mass and inertia properties from ADVISOR to

ADAMS/CarADAMS/Car.Optionally, geometry may be specified in web interface

- Run standard handling maneuvers in ADAMS/CarRun standard handling maneuvers in ADAMS/Car

Export to ADAMS/Car

Why?Faster simulationsQuick estimate of handling performance of hybrid vehicle

Example: allows analysis of battery pack location(often a large mass) and effect on handling

Information flow:

Simulation of a Hybrid Electric vehicle

• A default parallel HEV is simulated. The parameters can be obtained by just inserting ‘parallel’ in ‘drivetrain config’menu boxmenu box

• Objective is to minimize the engine size meeting the constraintsengine size, meeting the constraints

Constraints0 – 60 mph <= 12 s40 – 60 mph <= 5.3s0 – 85 mph <= 23.4sdistance in 5 s >= 140 fttime in 0.25mi <= 20smax. accel. Rate >= 17 ft/s2max. speed >= 90mphgradeability = 6% at 55mph g y p

Meets the constraints at 41 kW

Simulation of a Hybrid Electric vehicle

meets constraints at 40 kW

meets constraints at 39 kW

Simulation of a Hybrid Electric vehicle

meets constraints at 38 kW

Fails to meet the grade-constraints at 37 kW

Minimum size of engine for this config. Can be 38 kW

Limitations

Analysis tool, and not originally intended as a detailed designtooltool

Component models are quasi-static, and cannot be used topredict phenomena with a time scale of less than a tenth of asecond or so

Physical vibrations, electric field oscillations and other dynamics cannot be captured using ADVISOR, however recent linkages with other tools such as Saber Simplorer andrecent linkages with other tools such as Saber, Simplorer, and Sinda/Fluint allow a detailed study of these transients in those tools with the vehicle level impacts linked back into ADVISOR

Questions & Comments?Questions & Comments?