nickel-metal hydride battery simplified simulink model using matlab

Nickel-Metal Hydride 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 Ni-Mh Battery 4. Concept of the Model 5. Pin Configurations 6. Ni-Mh 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 – 1.35Ah (0.2C discharge) 6.2.2 Discharge Time Waveform – 1.35Ah (1.0C discharge) 6.2.3 Discharge Time Waveform – 1.35Ah (2.0C discharge) 6.2.4 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=7 7.1.2 Charge Time Waveform - NS=7 7.2.1 Discharge Time Circuit - NS=7 7.2.2 Discharge Time Waveform - NS=7 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 Ni-Mh battery

runtime and circuit performance.

• The model can be easily adjusted to your own Ni-Mh 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 Ni-Mh Battery Simplified Simulink Model is for users who require the

model of a Ni-MH Battery as a part of their system.

• The model accounts for Battery Voltage(Vbat) vs. Battery Capacity Level

(SOC) Characteristic, so it can perform battery charge and discharge time at

various current rate conditions.

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

neglected.

2. Model Feature

4

Battery Circuit Model

All Rights Reserved Copyright (C) Siam Bee Technologies 2015

2

MINUS

1

PLUS

3. Simulink Model of Ni-Mh Battery

5

Equivalent Circuit of Ni-Mh Battery Model using Matlab


4. Concept of the Model

6

Ni-Mh 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 Ni-Mh 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 Ni-Mh 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 = 0.3, 1.4, or 2.8 [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. Ni-Mh Battery Specification (Example)

• The battery information refer to a battery part number HF-A1U of SANYO.

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

Table 1

Nominal Voltage 1.2V

Capacity

Typical 1350mAh

Minimum 1250mAh

Charging Current Time 1350mA about 1.1h

Discharge cut-off voltage 1.0V

Battery capacity

[Typ.] is input as a

model parameter


6.1 Charge Time Characteristic

9

• Capacity: 1.35Ah • Charging Current: 1.35A about 1.1hrs

20°C

Datasheet Simulation

SOC=0 means battery

start from 0% of

capacity (empty)


(Second)


6.1.1 Charge Time Characteristic Simulation Circuit

10

Input Voltage



Charging Current


6.1.2 Charge Time Characteristic Simulation Settings


Table 2: Simulation settings

Property Value

StartTime 0

StopTime 3900

AbsTol auto

InitialStep auto

ZcThreshold auto

MaxConsecutiveZCs 1000

NumberNewtonIterations 1

MaxStep 1

MinStep auto

MaxConsecutiveMinStep 1

RelTol 1e-3

SolverMode Auto

Solver ode23t b

SolverName ode23t b

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 0.2C, 1.0C, and 2.0C discharge rates.

Battery starts from

100% of capacity

(fully charged)


13

0.2C discharge (0.27A)


6.2.1 Discharge Time Waveform 1.35Ah (0.2C discharge)

• Nominal Voltage: 1.2 [Vdc] /Cell

• Discharge cut-off voltage: 1.0V

• Capacity: 1.35Ah

• 0.2C discharge (0.27A)

(Second)


14








(Second)


15








(Second)



6.2.4 Discharge Time Characteristic Simulation Settings


Property Value

StartTime 0

StopTime 17802, 3450, 1650

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


Datasheet




• Discharge: 0.27A, 1.35A, 2.7A

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

0 250 500 750 1000 1250 1500

Cell

Vo

ltag

e [V

]

Discharge Capacity [mAh]

0.2C (270mA)

1.0C (1350mA)

2.0C (2700mA)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 1 2 3 4 5

Actu

al C

apacity

(% o

f R

ate

d C

apacity)

Discharge Rate (Multiples of C)

Mesurement

Simulation

2700mA

Simulation

1350mA 270mA


6.3.1 Vbat vs. SOC Characteristic Simulation Circuit


• Battery voltage vs. SOC are simulated at 0.2C, 1.0C, and 2.0C discharge rates.




• Discharge Current: 0.27A, 1.35A, 2.7A

Discharge Current


6.3.2 Vbat vs. SOC Characteristic Simulation Settings



Property Value

StartTime 0

StopTime 17802, 3450, 1650

AbsTol auto

InitialStep auto

ZcThreshold auto



MaxStep 10

MinStep auto


RelTol 1e-3

SolverMode Auto

Solver ode23t

SolverName ode23t








Voltage - Rated 8.4V

Capacity 1500mAh

Structure 1 Row x 7 Cells Side to Side

Number of Cells 7

• The battery information refer to a battery part number HHR-150AAB01F7

of Panasonic.


7. Extend the number of Cell (Example)

The number of cells

in series is input as

a model parameter Basic Specification

Ni-MH needs 7

cells to reach this

voltage level

2.1

4.8

VoltageNominal MH-Ni

RatedVoltageNS


7.1.1 Charge Time Circuit NS=7


Input Voltage

Number of Cells

1 minute into a second

(in simulation)




7.1.2 Charge Time Waveform NS=7


BATTERY PACK NIMH 8.4V

Number of Cells: 7

20°C

(min.)


SOC=0 means battery

start from 0% of

capacity (empty)


(in simulation)

1 Cell


7.2.1 Discharge Time Circuit NS=7


• Voltage - Rated: 8.4V

• Capacity: 1.5Ah

• Discharge Current: 1.5A (1.0C)

Number of Cells


(in simulation)



7.2.2 Discharge Time Waveform NS=3

• Voltage - Rated: 8.4V • Capacity: 1.5Ah • Discharge Current: 1.5A

BATTERY PACK NIMH 8.4V

Number of Cells: 7

20°C

(min.)


battery starts from 100%

of capacity (fully charged)


(in simulation)

1 Cell


7.3 Charge & Discharge Time Simulation Settings



Property Value

StartTime 0

StopTime 72, 57.5

AbsTol auto

InitialStep auto

ZcThreshold auto



MaxStep 0.01

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

27

Simulations Folder name

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

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

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

4. Charge Time Characteristic – NS=7......................................

5. Discharge Time Characteristic – NS=7..................................

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

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