Design Kit - CYBERNET

PV Li-Ion Battery System

All Rights Reserved Copyright (C) Bee Technologies Corporation 2010 1

Design Kit

Contents

Slide #

1. Lithium-Ion Batteries Pack1.1 Lithium-Ion Batteries Pack Specification..............................................................1.2 Discharge Time Characteristics...........................................................................1.3 Single Cell Discharge Characteristics..................................................................1.4 Charge Time Characteristics................................................................................

2. Solar Cells2.1 Solar Cells Specification......................................................................................2.2 Output Characteristics vs. Incident Solar Radiation.............................................

3. Solar Cell Battery Charger.........................................................................................3.1 Concept of Simulation PV Li-Ion Battery Charger Circuit.....................................3.2 PV Li-Ion Battery Charger Circuit........................................................................3.3 Charging Time Characteristics vs. Weather Condition.........................................3.4 Concept of Simulation PV Li-Ion Battery Charger Circuit + Constant Current......3.5 Constant Current PV Li-Ion Battery Charger Circuit.............................................3.6 Charging Time Characteristics vs. Weather Condition + Constant Current..........

4. Simulation PV Li-Ion Battery System in 24hr.4.1 Concept of Simulation PV Li-Ion Battery System in 24hr.....................................4.2 Short-Circuit Current vs. Time (24hr.)..................................................................4.3 PV-Battery System Simulation Circuit..................................................................4.3 PV-Battery System Simulation Result..................................................................

Simulations index............................................................................................................

3456

789101112131415

16171819-2324

2All Rights Reserved Copyright (C) Bee Technologies Corporation 2010

BAYSUN’s Lithium-Ion Batteries Pack : Power Battery Plus (PBT-BAT-0001)

• Capacity............................65[Wh], 4400[mAh] (Approximately)

• Rated Current....................3[A]

• Input Voltage.......................20.5 [Vdc]

• Output Voltage....................12.8 ~ 16.4 [Vdc] ( 4 cells )

• Charging time......................5[hours] (Approximately)

1.1 Lithium-Ion Batteries Pack Specification


1.2 Discharge Time Characteristics


0.2C ( 880 mA )0.5C ( 2200 mA )

1C ( 4400 mA )

Batteries Pack Model Parameters

NS (number of batteries in series) = 4 cellsC (capacity) = 4400 mASOC1 (initial state of charge) = 100%TSCALE (time scale) , simulation : real time

1 : 3600s or 1s : 1h

Discharge Rate : 0.2C(880mA), 0.5C(2200mA), and 1C(4400mA)

0

Hi

0

DMOD

D1

Voch16.8Vdc0

+ -U1PBT-BAT-0001

TSCALE = 3600SOC1 = 100

C11n

0IN-

OUT+

OUT-

IN+

G1

limit(V(%IN+, %IN-)/0.01, 0, rate*CAh )GVALUE

PARAMETERS:rate = 1CAh = 4400m

TSCALE=3600 means time Scale (Simulation time :

Real time) is 1:3600

1.3 Single Cell Discharge Characteristics

• Single cell discharge characteristics are compared between measurement data and simulation data.


Measurement Simulation

2.00

2.50

3.00

3.50

4.00

4.50

-100102030405060708090100VO

LTAG

E [V

]

SOC [%]

0.2C ( 880mA )0.5C ( 2200mA )1.0C ( 4400mA )

Single cell

1.4 Charge Time Characteristics


SOC [%]

Vbatt [V] ICharge [A]Batteries Pack Model Parameters

NS (number of batteries in series) = 4 cellsC (capacity) = 4400 mASOC1 (initial state of charge) = 100%TSCALE (time scale) , simulation : real time

1 : 3600s or 1s : 1h

Charger Adaptor

Input Voltage = 20.5 VdcInput Current = 880 mA(max.)

IN-

OUT+

OUT-

IN+

G1

Limit(V(%IN+, %IN-)/0.1, 0, rate*CAh ) GVALUE

DMOD

D1

Voch16.8Vdc0

0

+ -U1PBT-BAT-0001

TSCALE = 3600SOC1 = 0

Vin20.5Vdc

0

Hi

0

C11n

PARAMETERS:rate = 0.2CAh = 4400m

BP Solar’s photovoltaic module : SX330

• Maximum power (Pmax)..............30[W]

• Voltage at Pmax (Vmp).............16.8[V]

• Current at Pmax (Imp)...............1.78[A]

• Short-circuit current (Isc)...........1.94[A]

• Open-circuit voltage(Voc)...........21.0[V]

2.1 Solar Cells Specification


502mm

595m

m

2.2 Output Characteristics vs. Incident Solar Radiation


SX330

+U1SX330SOL = 1

Parameter, SOL is added as normalized incident radiation,

where SOL=1 for AM1.5 conditions

SOL=1

SOL=0.5

SOL=0.16

SOL=1

SOL=0.5

SOL=0.16

Cur

rent

(A)

Pow

er (W

)

Voltage (V)

SX330 Output Characteristics vs. Incident Solar Radiation

3. Solar Cell Battery Charger

• Solar Cell charges the Li-ion batteries pack (PBT-BAT-001) with direct connect technique. Choose the solar cell that is able to provide current at charging rate or more with the maximum power voltage (Vmp) nears the batteries pack charging voltage.

• PBT-BAT-0001 (Li-ion batteries pack)

– Charging time is approximately 5 hours with charging rate 0.2C or 880mA

– Voltage during charging with 0.2C is between 14.7 to 16.9 V


14.7 V

14.9 V

0.2C or 880mA

3.1 Concept of Simulation PV Li-Ion Battery Charger Circuit


Lithium-Ion Batteries Pack

Photovoltaic Module

Over Voltage Protection Circuit

16.8V Clamp Circuit

PBT-BAT-0001 (BAYSUN)DC12.8～16.4V (4 cells)4400mAh

SX 330 (BP Solar)Vmp=16.8VPmax=30W

Short circuit current ISCdepends on condition: SOL

3.2 PV Li-Ion Battery Charger Circuit

• Input value between 0-1 in the “PARAMETERS: sol = ” to set the normalized incident radiation, where SOL=1 for AM1.5 conditions.


DMOD

D1

Voch16.8Vdc0

0

Hi

0

C11n

PARAMETERS:sol = 1

SX330

+U2SX330SOL = {sol}

0

pv

+ -U1PBT-BAT-0001


3.3 Charging Time Characteristics vs. Weather Condition

• Simulation result shows the charging time for sol = 1, 0.5, and 0.16.


sol = 1.00 sol = 0.50sol = 0.16

3.4 Concept of Simulation PV Li-Ion Battery Charger Circuit + Constant Current



Photovoltaic Module


16.8V Clamp Circuit



Constant Current Control Circuit

Icharge=0.2C (880mA)

Short circuit current ISCdepends on condition: SOL

3.5 Constant Current PV Li-Ion Battery Charger Circuit

• Input the battery capacity (Ah) and charging current rate (e.g. 0.2*CAh) in the • “PARAMETERS: CAh = 4400m and rate = 0.2 ” to set the charging current.


DMOD

D1

Voch16.8Vdc0

0

Hi

0

C11n

PARAMETERS:sol = 1

SX330

+U2SX330SOL = {sol}

0

pv

PARAMETERS:rate = 0.2CAh = 4400m

IN-

OUT+

OUT-

IN+

G1

Limit(V(%IN+, %IN-)/0.1, 0, rate*CAh)GVALUE

+ -U1PBT-BAT-0001


3.6 Charging Time Characteristics vs. Weather Condition(Constant Current)

• Simulation result shows the charging time for sol = 1, 0.5, and 0.16. If PV can generate current more than the constant charge rate (0.2A), battery can be fully charged in about 5 hour.


sol = 1.00 sol = 0.50sol = 0.16

4.1 Concept of Simulation PV Li-Ion Battery System in 24hr.



Photovoltaic Module


16.8V Clamp Circuit



DC/DC Converter

Vopen= (V)Vclose= (V)

The model contains 24hr. solar power data (example).

DC Load

VIN=10~18VVOUT=5V

VIN = 5VIIN = 1.5A

Low-Voltage Shutdown Circuit

4.2 Short-Circuit Current vs. Time (24hr.)

• Short-circuit current vs. time characteristics of photovoltaic module SX330 for 24hours as the solar power profile (example) is included to the model.


SX330

+

U2SX330_24H_TS3600

The model contains 24hr. solar power data

(example).

4.3 PV-Battery System Simulation Circuit


Ronof f 1

100dchth

Low-Voltage Shutdown Circuit

DC/DC Converter

DMOD

D1

Voch16.8Vdc0

0

batt

0

C1100nIC = 16.4

0

pv

+ -U1PBT-BAT-0001


SX330

+

U2SX330_24H_TS3600

batt1C310n

+-

+

-S2S

VON = 0.7VOFF = 0.3

ROFF = 10MEGRON = 0.01

0

0

IN+IN-

OUT+OUT-

ecal_Iomax

n*V(%IN+, %IN-)*I(IN)/5EVALUE

Iomax

0

IN+IN-

OUT+OUT-

E2

IF( V(lctrl) > 0.25 ,Lopen ,Lclose) EVALUE

0

PARAMETERS:Lopen = 14Lclose = 15.2

IN+IN-

OUT+OUT-

E1

IF(V(batt1)>V(dchth),5,0)EVALUERonof f

100

Conof f1nIC = 5

Lctrl

PARAMETERS:n = 1

I11.5Adc

0

OUT

IN+IN-

OUT+OUT-

E3

IF( I(OUT)-V(Iomax) > 0 ,n*V(%IN+, %IN-)*I(IN)/(I(OUT)+1u), 5 )EVALUE

out_dc

DMOD

D2

Conof f 1100n

IN-

OUT+

OUT-

IN+

G1

Limit( V(%IN+, %IN-)/0.1, 1m, 5*I(out)/(n*limit(V(%IN+, %IN-),10,25)) )

GVALUE

IN

Solar cell model with 24hr. solar

power data.

Lopen value is load shutdown voltage.

Lclose value is load reconnect voltage

Set initial battery voltage, IC=16.4, for

convergence aid.

SOC1 value is initial State Of Charge of

the battery, is set as 70% of full voltage.

7.5W Load (5Vx1.5A).

Simulation at 15W load, change I1 from 1.5A to 3A

4.3.1 Simulation Result (SOC1=100)

• C1: IC=16.4• Run to time: 24s (24hours in real world)• Step size: 0.01s


PV generated current

Battery current

Battery voltage

Battery SOC

DC/DC input current

DC output voltage

• .Options ITL4=1000

SOC1=100 Fully charged, stop charging

Battery supplies current when solar power drops.

PV module charge the battery

Charging time


• C1: IC=16.4• Run to time: 24s (24hours in real world)• Step size: 0.01s• SKIPBP



Battery current

Battery voltage

Battery SOC

DC/DC input current

DC output voltage


SOC1=70

V=Lopen

V=Lclose

Shutdown

Reconnect

Fully charged, stop charging



Charging time


• C1: IC=15• Run to time: 24s (24hours in real world)• Step size: 0.01s• Total job time = 2s



Battery current

Battery voltage

Battery SOC

DC/DC input current

DC output voltage


SOC1=30

V=Lopen

V=Lclose

Shutdown

Reconnect




Charging time


• C1: IC=14.4• Run to time: 24s (24hours in real world)• Step size: 0.01s• SKIPBP



Battery current

Battery voltage

Battery SOC

DC/DC input current

DC output voltage

• .Options RELTOL=0.01• .Options ITL4=1000

SOC1=10

V=Lclose

Shutdown

Reconnect




Charging time

4.3.5 Simulation Result (SOC1=100, IL=3A or 15W load)

• C1: IC=16.4• Run to time: 24s (24hours in real world)• Step size: 0.001s



Battery current

Battery voltage

Battery SOC

DC/DC input current

DC output voltage


SOC1=100 Fully charged, stop charging



Charging time

V=Lopen

Shutdown

V=Lopen

Shutdown

4.3.4 Simulation Result (Example of Conclusion)

The simulation start from midnight(time=0). The system supplies DC load 7.5W.• If initial SOC is 100%,

– this system will never shutdown.• If initial SOC is 70%,

– this system will shutdown after 5.185 hours (about 5:11AM.).– system load will reconnect again at 7:40AM (Morning).

• If initial SOC is 30%, – this system will shutdown after 1.633 hours (about 1:38AM.).– system load will reconnect again at 7:37AM (Morning).

• If initial SOC is 10%, – this system will start shutdown.– this system will reconnect again at 7:37AM (Morning).

• With the PV generated current profile, battery will fully charged in about 4.25 hours.

The simulation start from midnight(time=0). The system supplies DC load 15W.• If initial SOC is 100%,

– this system will shutdown after 3.897 hours (about 3:54AM.).– system load will reconnect again at 7:37AM (Morning).– this system will shutdown again at 8:28 PM (Night).

• With the PV generated current profile, battery will fully charged in about 5.5 hours.


Simulations index

Simulations Folder name

1. PV Li-Ion Battery Charger Circuit...................................................

2. Constant Current PV Li-Ion Battery Charger Circuit......................

3. PV-Battery System Simulation Circuit (SOC1=100).......................

4. PV-Battery System Simulation Circuit (SOC1=70).........................



7. PV-Battery System Simulation Circuit (SOC1=100, 15W).............

charge-sol

charge-sol-const

sol_24h_soc100

sol_24h_soc70

sol_24h_soc30

sol_24h_soc10

sol_24h_soc100_15W


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Design Kit - CYBERNET