2015 Solar Car Conference MathWorks Workshop

8/18/2019 2015 Solar Car Conference MathWorks Workshop

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© 2015 The MathWorks, Inc.

Modeling and Simulation of

Photovoltaic Solar Power Vehicle Systemsusing MATLAB and Simulink

Jerry Brusher, Ph.D.Education Technical MarketingMathWorks – Novi, MI



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INTEGRATION AND TEST

INTEGRATION AND TEST

IMPLEMENTATION

Embedded

Software HIL System

DESIGN

SYSTEM LEVEL DESIGN

Control ElectricalMechanical

REQUIREMENTS

Model-Based Design Process

T E

S T &

V E R I F I C A T I O N

Optimize system performance

by developing in a single

simulation environment

Save time by automatically

generating embedded code

Lower costs by using HIL tests

Produce better designs by

continuously comparing design

and specification



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Customer Successeswith Model-Based Design

Max Planck

Instituteprotein structure

analysis

EIM Grouphedge fund

management

LockheedMartinF-35 flight

control

Horizon Windforecasting

& risk analysis

Johns Hopkins

University APL

prosthetic armdevelopment

Texas

Instruments

advancedDSP design

Beth Israel Deaconess

Medical Center

improved MRI

accuracy

General MotorsTwo-Mode Hybrid

powertrain



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HEV: System-Level Design & Optimization



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Photovoltaic Solar Power Vehicle Systems

DC

Power

Sunlight

PV Panels Motor Drive Vehicle Dynamics

DC

Power

Battery Storage

Charge

Controller

Power Inverter

AC

Power



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Agenda

Model-Based Design: System-Level Context

Modeling electrical and electronic components

– PV cells, panels, arrays and batteries

– Power converters and inverters

Designing control algorithms for power electronics

– Voltage and current regulation

– Maximum power point tracking (MPPT)

Modeling vehicle dynamics and mechanical components

– Transmission, clutches and tires

Support for Student Competitions

– Software

– Learning Resources



How does a PV cell work?Anatomy of a PV cel l

Photogeneration: Short circuit current I sc is proportional to the number of

absorbed photons that cross the pn-junction (when photon energy hn > E gap ).

Charge separation: Open circuit voltage V oc depends on the pn-junction

diode-like characteristics, V oc < E gap /q (where q is the elementary charge on

an electron).

anti-reflective layer

p-type

n-type

pn-junction

backplane

0.6 – 0.7 VoltsE gap



p

s NV

IRV

s ph R

IRV 1)(e I I I t

s

Where:I ph Solar induced current (proportional to irradiance)

I s Diode saturation current (exponential behavior)

N Diode quality factor (emission coefficient)

V t Thermal voltage kT/q (k : Boltzmann constant, T : device

temperature)

R p Shunt resistance (models leakage currents, primarily due to

defects)

R s Series resistance (models bulk and contact resistances)

How does a PV cell work?PV Cell Equ ivalent Circu it



Model Using Fundamental Approaches

First Principles

Simulink

Physical Components

Simscape

Advanced Components Library

SimElectronics



SimMechanics™

Mechanic al dyn amics (3-D)

SimDriveline™

Drivetrain sys tems (1-D)

SimHydraulics ®

Fluid power and contro l

Mult i -domain ph ysical systems

Electr ical pow er systems

SimPowerSystems™

SimElectronics™

Electromech anical and

electronic s ystems

Simscape™

Physical Modeling in Simulink ®



Model using experimental test data

Programmable Solar Array Simulator

i.e. Agilent E4360A

Import your test data Generate surface fit for

experimental V-I curves

Use 2D Lookup Table

model in simulation

PV panels under test

or



Curve Fitting Toolbox

Optimization Toolbox

Neural Network Toolbox

System Identification Toolbox

Data Driven Modeling in Simulink ®




DC

Power

Sunlight


DC

Power

Battery Storage

Charge Controller

Power Inverter

AC

Power



Battery Models:

Generic, Pre-Defined

Generic: SimElectronics

– Charge-dependent voltage source

– Parameters found on data sheets

Pre-Defined: SimPowerSystems

– Several pre-defined models

– Full parameterization

– Documentation provides

extensive detail



Battery Models:

Custom Cell

Use supplied components or

build new components via

Simscape language

Battery cell equivalent discharge circuitResistors, capacitor, and voltage source

are dependent upon SOC, DOC,

and temperature



Simscape Language For Modeling

Custom Components

MATLAB-based language,enabling text-based

authoring of physical

modeling components,

domains, and libraries – Leverages MATLAB

– Object-oriented for model reuse

– Generate Simulink blocks

– Save as binary to protect IP




DC

Power

Sunlight


DC

Power

Battery Storage

Charge Controller

Power Inverter

AC

Power



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Model DC to DC Power Converters

Construct, test and re-use multiple power electronic

converter topologies quickly and efficiently

Buck (step-dow n) Converter

Bo os t (step-up) Converter

Buc k-Boost Converter



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Model DC to DC Power Converters

Balance model fidelity and simulation speed according

to your needs

SimElect ronics Nonlinear simultaneous equations solution

Include temperature effects

SPICE level switching device models

Detailed simulation

SimPowerSystems Piecewise linear systems solution

Multiphase bridges and pulse generators

Transient and harmonic analysis

Faster simulation



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Model DC to AC Power Inverters

Build complex, multi-phase, multi-level inverter circuits using the UniversalBridge from the SimPowerSystems library

Use the built-in tools in SimPowerSystems to perform harmonic analysis

directly on your simulation model

Use average voltage models or ideal switching algorithms for control

design and faster simulation



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Use Simul ink Contro l Design and the Contro l System Toolbo x to linearize

your model and interactively design controllers against requirements in the

time and frequency domain

Once designed, test and verify the performance of your controller against the

nonlinear model

Voltage or Current Regulation



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Maximum Power Point Tracking

In general, when a module is directly connected to a load, the operatingpoint is seldom the MPP

A power converter is needed to adjust the energy flow from the PV

array to the load

Multiple well-known direct control algorithms are used to perform the

maximum power point tracking (MPPT)

Voltage & Current

SensingPWM Generator

MPPT Algorithm + Duty Cycle Adjustment

PV ArrayPower

Converter Load



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Incremental Conductance Algorithm Based on the differentiation of the PV array

power versus voltage curve:

The MPP will be found when:

Where I/V represents the instantaneous

conductance of the PV array and dI/dV is the

instantaneous change in conductance. The comparison of those two quantities tells

us on which side of the MPP we are currently

operating.

dV

dI V I

dV

dI V

dV

dV I

dV

VI d

dV

dP

)(

dV

dI

V

I

dV

dI V I

dV

dP 00

Flowchart of the Incremental Conductance MPPT Algorithm



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Incremental Conductance Algorithm Based on the differentiation of the PV array

power versus voltage curve:

The MPP will be found when:

Where I/V represents the instantaneous

conductance of the PV array and dI/dV is the

instantaneous change in conductance. The comparison of those two quantities tells

us on which side of the MPP we are currently

operating.

dV

dI V I

dV

dI V

dV

dV I

dV

VI d

dV

dP

)(

dV

dI

V

I

dV

dI V I

dV

dP 00

STATEFLOW Chart



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DC

Power

Sunlight


DC

Power

Battery Storage

Charge Controller

Power Inverter

AC

Power



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DC

Power

Sunlight


DC

Power

Battery Storage

Charge Controller

Power Inverter

AC

Power



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Mechanical Drivetrain: SimDriveline

Power Split Device

– Planetary gear, from

gear libraries in SimDriveline

Full Vehicle Model – Tire models

Transient and steady-state dynamics

– Longitudinal dynamics

Relevant for fuel economy studies

Engine Model

– Lookup-table relating speed to available power

Extend models using Simscape language or Simulink



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MathWorks Support for American Solar

Challenge

Complimentary

Software for teams to

use for the competition

On-demand webinars

Free MATLAB and

Simulink Tutorials

Learn More: American Solar Challenge Resource Page on MathWorks Website

http://www.mathworks.com/academia/student-competitions/american-solar/

http://www.mathworks.com/academia/student-competitions/american-solar/



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Summary

Model individual electrical and electronic components

using fundamental equations, physical components

and/or experimental data

Switch between different levels of detail in your

component models to manage fidelity and speed asneeded

Design and tune control algorithms and test them

against requirements in time and frequency domain

Optimize the overall system performance in simulation



Q&A

Documents

2015 Solar Car Conference MathWorks Workshop