Lead-Acid Battery Simplified Simulink Model using MATLAB

Lead-Acid Battery Simplified Simulink Model

using Matlab

All Rights Reserved Copyright (C) Siam Bee Technologies 2015 1

MATLAB Version

Bee Technologies

Contents

1. Benefit of the Model 2. Model Feature 3. Simulink Model of Lead-Acid Battery 4. Concept of the Model 5. Pin Configurations 6. Lead-Acid Battery Specification (Example) 6.1 Charge Time Characteristic 6.1.1 Charge Time Characteristic (Simulation Circuit) 6.1.2 Charge Time Characteristic (Simulation Settings) 6.2 Discharge Time Characteristic 6.2.1 Discharge Time Waveform - 50Ah (0.1C discharge) 6.2.2 Discharge Time Waveform - 50Ah (0.23C discharge) 6.2.3 Discharge Time Waveform - 50Ah (0.65C discharge) 6.2.4 Discharge Time Waveform - 50Ah (1.0C discharge) 6.2.5 Discharge Time Characteristic (Simulation Settings) 6.3 Vbat vs. SOC Characteristic 6.3.1 Vbat vs. SOC Characteristic (Simulation Circuit) 6.3.2 Vbat vs. SOC Characteristic (Simulation Settings) 7. Extend the number of Cell (Example) 7.1.1 Charge Time Circuit - NS=3 7.1.2 Charge Time Waveform - NS=3 7.2.1 Discharge Time Circuit - NS=3 7.2.2 Discharge Time Waveform - NS=3 7.3 Charge & Discharge Time (Simulation Settings)

8. Port Specifications

Simulation Index

2 All Rights Reserved Copyright (C) Siam Bee Technologies 2015

1. Benefit of the Model

• The model enables circuit designer to predict and optimize Lead-Acid

battery runtime and circuit performance.

• The model can be easily adjusted to your own Lead-Acid battery

specifications by editing a few parameters that are provided in the

datasheet.

• The model is optimized to reduce the convergence error and the simulation

time.

All Rights Reserved Copyright (C) Siam Bee Technologies 2015 3

• This Lead-Acid Battery Simplified Simulink Model is for users who require

the model of a Lead-Acid Battery as a part of their system.

• Battery Voltage(Vbat) vs. Battery Capacity Level (SOC) Characteristic, that can

perform battery charge and discharge time at various current rate conditions,

are accounted by the model.

• As a simplified model, the effects of cycle number and temperature are

neglected.

2. Model Feature

4

Battery Circuit Model

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2

MINUS

1

PLUS

3. Simulink Model of Lead-Acid Battery

5

Equivalent Circuit of Lead-Acid Battery Model using Matlab


4. Concept of the Model

6

Lead-Acid battery

Simplified Simulink Model

[Spec: C, NS]

Adjustable SOC : 0-100(%)

+

-

• The model is characterized by parameters: C, which represent the battery

capacity and SOC, which represent the battery initial capacity level.

• Open-circuit voltage (VOC) vs. SOC is included in the model as a behavioral

model.

• NS (Number of Cells in series) is used when the Lead-Acid cells are in series

to increase battery voltage level.

Output Characteristics

All Rights Reserved Copyright (C) Bee Technologies Corporation 2015 All Rights Reserved Copyright (C) Siam Bee Technologies 2015

5. Pin Configurations

• From the Lead-Acid Battery specification, the model is characterized by setting parameters

C, NS, SOC and TSCALE.

7

Model Parameters:

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Probe

“SOC”

C is the amp-hour battery capacity [Ah]

– e.g. C = 1, 50, or 100 [Ah]

NS is the number of cells in series

– e.g. NS=1 for 1 cell battery, NS=2 for 2 cells battery (battery voltage is double from 1 cell)

SOC is the initial state of charge in percent

– e.g. SOC=0 for a empty battery (0%), SOC=100 for a full charged battery (100%)

TSCALE turns TSCALE seconds(in the real world)

into a second(in simulation)

– e.g. TSCALE=60 turns 60s or 1min (in the real world) into a second(in simulation), TSCALE=3600 turns 3600s or 1h into a second.


6. Lead-Acid Battery Specification (Example)

• The battery information refer to a battery part number MSE Series of GS YUASA.

8

Battery capacity is input

as a model parameter


Table 1

Nominal Voltage 2.0 [Vdc] /Cell

Capacity 50Ah

Rated Charge 0.1C10A

Voltage Set 2.23 [Vdc] /Cell

Charging Time 24 [hours] @ 0.1C10A


6.1 Charge Time Characteristic

9

• Voltage Set: 2.23V /Cell • Charging Current: 5.0A (0.1C Charge) • Charging Time: 24 [hours] @ 0.1C10A

Current: 5A (0.1C10A)

Voltage Set=2.23V

Datasheet Simulation


%SOC

(Second)


6.1.1 Charge Time Characteristic Simulation Circuit

10

Over-Voltage Protector:

(Charging Voltage 1) - VF of Diode

Input Voltage


SOC=0 means battery

starts from 0% of

capacity (empty)

Charging Current


6.1.2 Charge Time Characteristic Simulation Settings

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Table 2: Simulation settings

Property Value

StartTime 0

StopTime 100000

AbsTol auto

InitialStep auto

ZcThreshold auto

MaxConsecutiveZCs 1000

NumberNewtonIterations 1

MaxStep 10

MinStep auto

MaxConsecutiveMinStep 1

RelTol 1e-3

SolverMode Auto

Solver ode23t

SolverName ode23t

SolverType Variable-step

SolverJacobianMethodControl auto

ShapePreserveControl DisableAll

ZeroCrossControl UseLocalSettings

ZeroCrossAlgorithm Adaptive

SolverResetMethod Fast


6.2 Discharge Time Characteristic


• Battery voltage vs. time are simulated at 0.1C, 0.23C, 0.65C and 1.0C discharge rates.

Datasheet

• Battery starts from 100% of capacity (fully charged)


13

0.1C discharge (5A)


6.2.1 Discharge Time Waveform 50Ah (0.1C discharge)

• Nominal Voltage: 2.0 [Vdc] /Cell

• Capacity: 50Ah

• 0.1C discharge (5.0A)

(Second)


14

0.23C discharge (11.5A)




• Capacity: 50Ah


(Second)


15

0.65C discharge (32.5A)




• Capacity: 50Ah


(Second)


16

1.0C discharge (50A)




• Capacity: 50Ah

• 1.0C discharge (50A)

(Second)



6.2.4 Discharge Time Characteristic Simulation Settings


Property Value

StartTime 0

StopTime 36000, 13932, 3420, 1836

AbsTol auto

InitialStep auto

ZcThreshold auto



MaxStep 10

MinStep auto


RelTol 1e-3

SolverMode Auto

Solver ode23t

SolverName ode23t








6.3 Vbat vs. SOC Characteristic


0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 1 2 3

(% o

f R

ate

d C

apacity)

Discharge Rate (Multiples of C)

Mesurement

Simulation

Datasheet Simulation

@25C

@25C


• Capacity: 50Ah

• 0.1C, 0.25C, 0.6C, 1.0 and 3.0C (discharge rates)


6.3.1 Vbat vs. SOC Characteristic Simulation Circuit


Battery starts from

100% of capacity

(fully charged)

• Battery voltage vs. SOC are simulated at 0.1C, 0.25C, 0.6C and 1.0C discharge rates.

Discharge Current


6.3.2 Vbat vs. SOC Characteristic Simulation Settings



Property Value

StartTime 0

StopTime 36000, 12600, 3780, 1836

AbsTol auto

InitialStep auto

ZcThreshold auto



MaxStep 10

MinStep auto


RelTol 1e-3

SolverMode Auto

Solver ode23t

SolverName ode23t








• The battery information refer to a battery part number MSE-100-6 of GS YUASA.


7. Extend the number of Cell (Example)

Voltage - Rated 6.0 [Vdc] /Cell

Capacity 100Ah

Rated Charge 0.1C10A

Voltage Set 2.23V*3 [Vdc] /Cell

Charging Time 24 [hours] @ 0.1C10A

Basic Specification

Lead-Acid needs 3 cells

to reach this voltage level The number of cells

in series is input as

a model parameter

0.2

6

Acid-Lead

VoltageNominal

RatedVoltageNS


7.1.1 Charge Time Circuit NS=3

22

Over-Voltage Protector:

(Voltage Set 3) - VF of Diode


Number of Cells

1 hour into a second (in

simulation)

Charging Current

Input Voltage


23

• Voltage Set: 2.23V 3

• Capacity: 100Ah

• Charging Current: 10A (0.1 Charge)

Voltage Set=6.69V

(hour)

The battery needs 24 hours to be fully charged


7.1.2 Charge Time Waveform NS=3

Current: 10A (0.1C)


7.2.1 Discharge Time Circuit NS=3


• Battery voltage vs. time are simulated at 0.1C discharge rate.

• Nominal Voltage: 2.0V 3

• Capacity: 100Ah

• Discharge Current: 10A (0.1C)

Number of Cells

1 hour into a second

(in simulation)

Discharge Current


25

(hour)

10A (0.1C) Nominal voltage: 6.0V


7.2.2 Discharge Time Waveform NS=3

• Nominal Voltage: 2.0V 3

• Capacity: 100Ah

• Discharge Current: 10A (0.1C)


7.3 Charge & Discharge Time Simulation Settings



Property Value

StartTime 0

StopTime 24, 10

AbsTol auto

InitialStep auto

ZcThreshold auto



MaxStep 0.1

MinStep auto


RelTol 1e-3

SolverMode Auto

Solver ode23t

SolverName ode23t








8. Port Specifications


Table 6

Parameter Simulink Simscape

NS O

C O

TSCALE O

%SOC O

VSOC O

PLUS O

MINUS O

Battery Model


Simulation Index

28

Simulations Folder name

1. Charge Time Characteristic..................................................

2. Discharge Time Characteristic..............................................

3. Vbat vs. SOC Characteristic...................................................

4. Charge Time Characteristic – NS=3......................................

5. Discharge Time Characteristic – NS=3..................................

Charge_Time

Discharge_Time

Discharge_SOC

Charge_Time(NS)

Discharge_Time(NS)

All Rights Reserved Copyright (C) Bee Technologies Corporation 2015 All Rights Reserved Copyright (C) Siam Bee Technologies 2015

Engineering

Lead-Acid Battery Simplified Simulink Model using MATLAB