©20

05 T

he M

athW

orks

, Inc

.

Modeling a Hybrid Electric Vehicle and Controller to Optimize System Performance

Steve Miller

Technical Marketing, Physical Modeling Tools

The MathWorks GmbH, Munich, Germany

Steve.Miller@mathworks.de

Root Locus Bode Plot

Real Axis Frequency

Controller+-Ref.

Speed

Controller+-

Ref. Voltage

2

Key Results

1) Integrating the requirements in model and simulation is critical for effective development

2) Effective use of control design toolsand optimization algorithms improves overall design

3) Simulating plant and controller in one tool allows engineers to understand and optimize performance of the entire system

Root Locus Bode Plot

Real Axis Frequency

3

Agenda

Introduction to HEV Model 5 minImproving Development Process 5 min

– Linking Design and Specification– Comparing Performance and Specification

Optimizing HEV System 15 min– Linearized Model– Nonlinear Model

Questions and Answers 5 min

4

System Optimization Challenge

HEV with two PI controllers– Speed Controller, Voltage Controller

Must meet performance requirementsConflicting goals

– Improving speed response degradesvoltage bus response

Command

Voltage Bus

VoltageDC-DC

Converter

Duty Cycle

+- ControllerCommand

Speed Vehicle

SpeedCommand

Torque

+-Controller

5

HEV Electromechanical System

Battery

SimPowerSystemsSimulink

SimPowerSystemsSimulink

SimDrivelineSimscapeSimPowerSystemsSimulink

BrakingChopper

Three-PhaseBridge

6

Simscape

Extension of Simulink® designed to model multidomain physical systemsEases process of modeling physical systems

– Does not require deriving and programming the equations of motion for the system

Used by system engineers and control engineers to build a model representing the physical structure of the system

V+

V-

MATLAB®, Simulink®

Sim

Pow

erS

yste

ms

Simscape

Sim

Mec

hani

cs

Sim

Driv

elin

e

Sim

Hyd

raul

ics®

P TT

A B

7

Electrical System in SimPowerSystems

Permanent Magnet Synchronous Motor Drive

– Speed controller– Vector controller– Inverter– Permanent magnet

synchronous motor– Braking chopper

Implemented throughSimPowerSystems in the Simulink environment

SimPowerSystems Blocks

8

Mechanical System in SimDriveline

Transmission System– Input Torque– Transmission– Vehicle Inertia

Implemented in SimDriveline within the Simulink environment

TransmissionVehicleInertia

InputTorque

WheelSpeed

SimDriveline Blocks

9

Agenda

Introduction to HEV Model 5 minImproving Development Process 5 min

– Linking Design and Specification– Comparing Performance and Specification

Optimizing HEV System 15 min– Linearized Model– Nonlinear Model

Questions and Answers 5 min

10

Linking Specification and Design

Problem: Matching design tospecification is difficult.

Solution: Use SimulinkVerification and Validation to directlylink the design to the specification.

Situation:

Part Numbers

HEV Requirements1. Drivetrain SystemLayout

11

Comparing Specification and Design

Problem: Measuring design performance relative to specification is difficult.

Solution: Use Simulink Verificationand Validation to automatically compareperformance to specification.

Situation:

HEV Requirements1. Drivetrain System

Wheel Speed5% Setting Timein 0.5 Sec

12

Improved Development Process

Advantages of improved process

1) Enables quick and easy associaton of specification and model

2) Automatically checks design against specification

3) Supports Model-Based Design, helping you discover and solve problems earlier in the design process

13

Agenda

Introduction to HEV Model 5 minImproving Development Process 5 min

– Linking Design and Specification– Comparing Performance and Specification

Optimizing HEV System 15 min– Linearized Model– Nonlinear Model

Questions and Answers 5 min

14

Possibilities for System Optimization

Nonlinear model– Specify response

characteristics– Automatic tuning via

Simulink Response Optimization

Linearized model– Linearize system via Simulink

Control Design– Perform linear control design with

Control System Toolbox andSimulink Response Optimization

– Retest in nonlinear system

Controller+-

Controller+-

A x + B uRoot Locus Bode Plot

Real Axis Frequency

15

System Optimization On Linear Plant

Problem: Design and tune thetwo controllers in this system tomeet system requirements.

Solution: Use Simulink Control Design, Control System Toolbox todesign, tune, and test the controller

Model:

Controller+-Ref.

Speed

Controller+-

Ref. Voltage

16

Steps to Design Controller1) Identify control loops

of interest

2) Identify operating point

3) Linearize model about this point

4) Perform control design

5) Test controller in nonlinear system

A x + B u = 0Comman

dVolta

ge

Vehicl

eSpee

d

+-

+-

ControllerController

Root Locus Bode Plot

Real Axis Frequency

System Optimization On Linear Plant

Command

Speed

BusVolta

ge

17

System Optimization On Linear Plant

Advantages of Simulink Control Design

1) Enable easy application of linear control theoryOperating points from specification or simulationGraphical design with interactive plots

2) Rapid evaluation of designs with interactive analysis plots

3) Optimize performance based on time, frequency, or root locus constraints

18

System Optimization On Nonlinear Plant

Problem: Design and tune thecontroller in this system tomeet system requirements.

Solution: Use Simulink Response Optimization to design, tune, and test the controller

Model:

Kp Ki Kp Ki

3.0 62.80.033

R

0.001 0.08(Kps+Ki)s

Controller+-Ref.

Speed

Controller+-

Ref. Voltage

(Kps+Ki)s

Voltage

Speed

Voltage Speed Motor

Kp Ki Kp Ki

2.2 75.10.023

R

0.003 0.07

Kp Ki Kp Ki

1.9 83.90.014

R

0.005 0.06

Kp Ki Kp Ki

1.5 95.70.001

R

0.006 0.05

Kp Ki Kp Ki

1.3 1200.001

R

0.007 0.05

19

Control Design On Nonlinear Plant

Steps to Optimizing Response

1) Identify parameters to be tunedand their ranges

2) Specify desired response

3) Perform response optimization

(Kps+Ki)s

20

Control Design On Nonlinear Plant

Advantages of Simulink Response Optimization

1) Simulating plant and controller in one tool allows engineers to understand and optimize performance of the entire system

2) Automatic tuning of parameters saves time

3) Graphical interface makes it easy to map specification to tests

21

Summary

1) Integrating the requirements in model and simulation is critical for effective development

2) Effective use of control design toolsand optimization algorithms improves overall design

3) Simulating plant and controller in one tool allows engineers to understand and optimize performance of the entire system

Root Locus Bode Plot

Real Axis Frequency

22

Agenda

Introduction to HEV Model 5 minImproving Development Process 5 min

– Linking Design and Specification– Comparing Performance and Specification

Optimizing HEV System 15 min– Linearized Model– Nonlinear Model

Questions and Answers 5 min

23

MathWorks Physical Modeling Tools Booth(HEV Example, Other Tools)

Series-Parallel architecture usingSimscape, SimDriveline, SimPowerSystems

24

Physical Modeling Master Class(Wednesday, 10:30 – 12:00)

Model and simulate multidomain physical systems all within the Simulink environment

Optimize system performanceby developing the plant and controller in one environment

Use Model-Based Design on your entire system to improveyour development process

s1 s2

s3

ProductionC-Code

SimulinkPlant Model

©20

05 T

he M

athW

orks

, Inc

.

Thank You ForYour Attention!

Steve Miller

Technical Marketing, Physical Modeling Tools

The MathWorks GmbH, Munich, Germany

Steve.Miller@mathworks.de