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PREDICTIVEPREDICTIVE

BATTERYBATTERY

MODELINGMODELING

Chris Dan Gore

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Sunseeker

Solar powered electric car Two parallel sets of 260 cell batteries

Gallium arsenide array (solar cells)

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Some History

1995 Car 2008 Car 2003 Car

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Car Electrical Layout

Sun

SolarCells

Power PointTracker Battery

Throttle

Motor Controller Motors+ Wheels

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Our Battery Pack (520 Li-Polymer Cells)

2008 Sunseeker Battery Pack

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Lithium-Polymer BatteryCell

LixMO2 + 6C Li(1-x) MO2 + LiC6

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Batteries areNondeterministic

Peukerts Law: Capacity = C/p(n-1)

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Current State of ChargeEstimation Methods

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Battery Discharge

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One Method forDetermining EMF

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Important Variables for SOCEstimation

St t f h ti ti

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State of charge estimationbased on evolutionary

neural network

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Artificial NeuralNetworks Inspired by biological neural networks in

the brain.

Supervised learning

Able to learn nonlinear systems Inherently parallelizable

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Biological Basis

Biological Neural Network Artificial Neural Network

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Activation Functions

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Backpropagation

Gradient Descent

Levenberg-Marquart

Rprop

Others

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Feed Forward NeuralNetwork

Activation Function:

Output:

Weight update:

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Weight UpdatingStrategy Pattern mode strategy: update weights

after each training pattern

Batch mode strategy: update weights

after a batch of training patterns

(Training patterns are just sets of samples)

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Parallelization of NeuralNetworks Parallelization of neurons

Parallelization of neural layers

Parallelization of training sets

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Parallelization ofNeurons

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Parallelization of Layers

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Parallelization of TrainingSets

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Ability to Generalize

One of the tougher goals of neuralnetworks

Means that the algorithm works for a

wide range of inputs

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4 Layer Design

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Online Training

Continuous feedback system

Makes decisions based on the currentstate of the system

Incremental

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Our Network

Vn

I

It

Tn

Tenv

Vn+1

Tn+1

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Test Bench

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Test Bench

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EMF Results

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What Next?

More test bench data

Data from the car

Improvement of generalizing algorithms

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SOC Estimation UsingSupport Vector Machines

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Thank You