PV Ni-MH Battery System (Output is DC)

PV Ni-MH Battery System (DC Out)

All Rights Reserved Copyright (C) Bee Technologies Corporation 2013 1

Design Kit

Contents

Slide #

1. Nickel - Metal Hydride Battery

1.1 Ni-MH Battery Specification.................................................................................

1.2 Discharge Time Characteristics...........................................................................

1.3 Battery Voltage vs. SOC Discharge Characteristics.............................................

1.4 Charge Time Characteristics................................................................................

1.5 Battery Voltage vs. SOC Charge Characteristics.................................................

2. Solar Cells

2.1 Solar Cells Specification......................................................................................

2.2 Output Characteristics vs. Incident Solar Radiation.............................................

3. Solar Cell Battery Charger.........................................................................................

3.1 Concept of Simulation PV Ni-MH Battery Charger Circuit....................................

3.2 PV Ni-MH Battery Charger Circuit........................................................................

3.3 Charging Time Characteristics vs. Weather Condition.........................................

3.4 Concept of Simulation PV Ni-MH Battery Charger Circuit + Constant Current.....

3.5 Constant Current PV Ni-MH Battery Charger Circuit............................................

3.6 Charging Time Characteristics vs. Weather Condition + Constant Current..........

4. Simulation PV Ni-MH Battery System in 24hr.

4.1 Concept of Simulation PV Ni-MH 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............................................................................................................

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4

5

6

7

8

9

10

11

12

13

14

15

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20-25

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2 All Rights Reserved Copyright (C) Bee Technologies Corporation 2013

KAWAZAKI’s Ni-MH Batteries : Gigacell (10-180)

• Rated Voltage ..................12 [V]

• Capacity............................177 [Ah] (Approximately)

• Energy Capacity................2.1 [kWh]

• Max Output........................48 [kW]

• Rated Charge................ 0.2C5 [A] ( SoC=100% )

1.1 Ni-MH Battery Specification


10 Ni-MH cells are

in series.

1.2 Discharge Time Characteristics


Batteries Pack Model Parameters

NS (number of batteries in series) = 1 Unit (10 Ni-MH cells)

C (capacity) = 177 Ah

SOC1 (initial state of charge) = 1 (100%)

TSCALE (time scale) , simulation : real time

1 : 3600s or

1s : 1h

Discharge Rate : 0.2C(35.4A), 0.5C(88.5A), 1C(177A) and 2C(354A)

TSCALE=3600

means “Time Scale”

(Simulation time :

Real time) is 1:3600

Time

0s 1.0s 2.0s 3.0s 4.0s 5.0s 6.0s

V(HI)

7V

8V

9V

10V

11V

12V

13V

14V

15V

16V

17V

0.2C ( 35.4A )

0.5C ( 88.5A )

1C ( 177A ) 2C ( 354A )

0

Hi

0

0

C1

1n

IN-

OUT+

OUT-

IN+

G1

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

PARAMETERS:

rate = 0.2CAh = 177

+ -U1GIGACELL_10-180

TSCALE = 3600

SOC1 = 1NS = 1

1.3 Battery Voltage vs. SOC Discharge Characteristics

• VBAT vs. SOC Discharge Characteristics are compared between measurement data and simulation

data.


Measurement Simulation

10 Ni-MH cells are in series for

total rated current 12V (Each

cell have 1.2V rated voltage).

7

8

9

10

11

12

13

14

15

16

17

0 0.2 0.4 0.6 0.8 1

Ba

tte

ry V

olt

ag

e (

V)

SOC (%)

0.2C, Dch 2.0C, Dch 5.0C, Dch 8.0C, Dch 11C, Dch

Time

0s 1.0s 2.0s 3.0s 4.0s 5.0s

V(HI)

7V

8V

9V

10V

11V

12V

13V

14V

15V

16V

17V

1.4 Charge Time Characteristics


Batteries Pack Model Parameters

NS (number of batteries in series) = 1 Unit (10 Ni-MH cells)

C (capacity) = 177 Ah

SOC1 (initial state of charge) = 1 (100%)

TSCALE (time scale) , simulation : real time

1 : 3600s or

1s : 1h

Charge Rate : 0.2C(35.4A), 0.5C(88.5A), and 1C(177A)

TSCALE=3600

means “Time Scale”

(Simulation time :

Real time) is 1:3600

0.2C ( 35.4A )

1C ( 177A )

0.5C ( 88.5A )

PARAMETERS:

rate = 0.2CAh = 177

IN-

OUT+

OUT-

IN+

G1

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

0

Vin18Vdc

0

0

C1

1n + -U1GIGACELL_10-180

TSCALE = 3600

SOC1 = 0NS = 1

HiHi

7

8

9

10

11

12

13

14

15

16

17

0 0.2 0.4 0.6 0.8 1

Ba

tte

ry V

olt

ag

e (

V)

SOC (%)

0.2C, Ch 2.0C, Ch 3.0C, Ch 5.0C, Ch

1.5 Battery Voltage vs. SOC Charge Characteristics

• VBAT vs. SOC Charge Characteristics are compared between measurement data and simulation

data.


Measurement Simulation

Suntech’s photovoltaic module : STP140D-12/TEA

• Maximum power (Pmax)............140[W]

• Voltage at Pmax (Vmp).............17.6[V]

• Current at Pmax (Imp)...............7.95[A]

• Short-circuit current (Isc)...........8.33[A]

• Open-circuit voltage(Voc)..........22.4[V]

2.1 Solar Cells Specification


1482m

m

V_V1

0V 5V 10V 15V 20V 25V

V(V1:+)*I(Isense)

0W

50W

100W

150W

SEL>>

I(Isense)

0A

2A

4A

6A

8A

10A

2.2 Output Characteristics vs. Incident Solar Radiation


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

Curr

ent

(A)

Pow

er

(W)

Voltage (V)

STP140D-12/TEA Output Characteristics vs. Incident Solar Radiation

+U1STP140D-12TEASOL = 1

Time

0s 1.0s 2.0s 3.0s 4.0s 5.0s

V(HI)

7V

8V

9V

10V

11V

12V

13V

14V

15V

16V

17V

3. Solar Cell Battery Charger

• Solar Cell charges the Ni-MH battery pack (STP140D-12/TEA) 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.

• Gigacell 10-180 (Ni-MH Battery)

– Charging time is approximately 5 hours with charging rate 0.2C or 35.4A

– Voltage during charging with 0.2C is between 11.8 to 14.2 V


11.8 V

14.2 V

0.2C or 35.4A

3.1 Concept of Simulation PV Ni-MH Battery Charger Circuit


Ni-MH Battery Photovoltaic

Module

Over Voltage

Protection Circuit

14.01V Clamp Circuit

Gigacell 10-180 (Kawasaki)

DC12V (10 cells)

177Ah

STP140D-12/TEA (Suntech)

10 panels (parallel)

Vmp=17.6V

Pmax=1.4kW

Short circuit current ISC

depends on condition: SOL

3.2 PV Ni-MH 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.


0 0 0 0

0 0 0 0

DMOD

D1

Voch14.01dc

0

0

Hi

0

C1

1n

PARAMETERS:

sol = 1

pv

+ -

U1GIGACELL_10-180TSCALE = 3600

SOC1 = 0NS = 1

+U2

STP140D-12TEASOL = {sol}

0

+U3

+U4

+U7

+U8

+U9

+U10

+U11

0

+U5

+U6

Time

0s 1s 2s 3s 4s 5s 6s 7s 8s 9s 10s

V(X_U1.SOC)

0V

0.25V

0.50V

0.75V

1.00V

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 = 0.50

sol = 0.16

3.4 Concept of Simulation PV Ni-MH Battery Charger Circuit

+ Constant Current



Module

Over Voltage

Protection Circuit



DC12V (10 cells)

177Ah

STP140D-12/TEA

(Suntech)


Vmp=17.6V

Pmax=1.4kW

Constant

Current

Control

Circuit

Icharge=0.2C (35.4A)

Short circuit current ISC

depends on condition: SOL

3.5 Constant Current PV Ni-MH Battery Charger Circuit

• Input the battery capacity (Ah) and charging current rate (e.g. 0.2*CAh) in the

• “PARAMETERS: CAh = 177 and rate = 0.2 ” to set the charging current.


0 00

0

0

00

PARAMETERS:

sol = 1

0

+U2

STP140D-12TEASOL = {sol}

0

+U3

+U4

+U7

+U8

+U9

+U10

+U11

0

+U5

+U6

pv

PARAMETERS:

rate = 0.2CAh = 177

IN-

OUT+

OUT-

IN+

G1

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

DMOD

D1

Voch14.01dc

0

0

0

Hi

C1

1n

+ -


SOC1 = 0NS = 1

Time

0s 1s 2s 3s 4s 5s 6s 7s 8s 9s 10s

V(X_U1.SOC)

0V

0.25V

0.50V

0.75V

1.00V

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 (0.2C), battery can be fully

charged in about 5 hour.


sol = 1.00

sol = 0.50

sol = 0.16

4.1 Concept of Simulation PV Ni-MH Battery System in 24hr.



Module

Over Voltage

Protection Circuit



DC12V (10 cells)

177Ah STP140D-12/TEA

(Suntech)


Vmp=17.6V

Pmax=1.4kW

DC/DC

Converter

Vopen=11. 6(V)

Vclose= 13.8(V)

The model contains 24hr.

solar power data (example).

DC Load

VIN=10~18V

VOUT=5V

VL = 5V

IL = 50A

Low-Voltage

Shutdown

Circuit

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

• Short-circuit current vs. time characteristics of photovoltaic module STP140D-12/TEA

for 24hours as the solar power profile (example) is included to the model.


The model contains

24hr. solar power data

(example).

+ U1

STP140D-12TEA_24H_TS3600

Time

0s 1s 2s 3s 4s 5s 6s 7s 8s 9s 10s 12s 14s 16s 18s 20s 22s 24s

I(Isense)

0A

5A

10A

15A

0

+ U2

STP140D-12TEA_24H_TS3600

+ U3+ U4

Ronof f 1

100dchth

+ U5

Low-Voltage Shutdown Circuit

+ U6

+ U7

DC/DC Converter

DMOD

D1

Voch14.01Vdc

0

0

batt

+ U8

0

+ U9+ U10

pv

+ U11

DMOD

D2

batt1+

-

+

-

S2S

VON = 0.7VOFF = 0.3

ROFF = 10MEGRON = 0.01m

0

0

C1

10n

IC = 13.7

IN+

IN-

OUT+

OUT-

ecal_Iomax

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

Iomax

0

C3

100n

IN+

IN-

OUT+

OUT-

E2

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

0

PARAMETERS:

Lopen = 11.6

Lclose = 13.8

IN+

IN-

OUT+

OUT-

E1

IF(V(batt1)>V(dchth),5,0)EVALUE

Conof f1nIC = 5

Ronof f100

Lctrl

PARAMETERS:

n = 1

I1

50Adc

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

+ -


SOC1 = 1NS = 1

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

0 00

0

0

00 0

0

4.3 PV-Battery System Simulation Circuit


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=13.7, for

convergence aid.

SOC1 value is initial

State Of Charge of

the battery, is set as

70% of full voltage.

250W Load

(5Vx50A).

Simulation at 500W load, change I1 from 50A to 100A

4.3.1 Simulation Result (SOC1=1, IL=50A or 250W load)

• C1: IC=13.7

• 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

• RELTOL=0.01

• ABSTOL=1.0u

• ITL4=1000

SOC1=1 (100%)

Fully charged,

stop charging

Battery supplies current when solar

power drops.

PV module charge the battery

Charging

time

When battery is discharging , current I(U1:PLUS) is minus and when the battery is charging, the current is plus.

Time

0s 3s 6s 9s 12s 15s 18s 21s 24s

1 V(out_dc) 2 I(IN)

0V

2.5V

5.0V

7.5V1

0A

50A2

>>

V(X_U1.SOC)

0V

1.0V

SEL>>

1 V(batt) 2 I(U1:PLUS)

12V

14V

16V1

-100A

0A

100A2

>>

I(pv)

0A

50A

100A

150A

Time

0s 3s 6s 9s 12s 15s 18s 21s 24s

1 V(out_dc) 2 I(IN)

0V

2.5V

5.0V

7.5V1

0A

25A

38A

50A2

>>

V(X_U1.SOC)

0V

1.0V

SEL>>699.201m)


10V

15V1

>> -50A

0A

50A2

(8.3138,13.797)

(5.7490,11.595)

I(pv)

0A

50A

100A

150A

4.3.2 Simulation Result (SOC1=0.7, IL=50A or 250W load)



Battery current

Battery voltage

Battery SOC

DC/DC input current

DC output voltage

SOC1=0.7

V=Lopen

V=Lclose

Shutdown

Reconnect

Fully charged,

stop charging


power drops.

Charging

time

• C1: IC=13.7



• .Options

• RELTOL=0.01

• ABSTOL=1.0u

• ITL4=1000

Time

0s 3s 6s 9s 12s 15s 18s 21s 24s

1 V(out_dc) 2 I(IN)

0V

2.5V

5.0V

7.5V1

0A

25A

38A

50A2

>>

V(X_U1.SOC)

0V

1.0V

SEL>>

,299.176m)


10V

15V1

-75A

25A

75A2

>>

(8.2938,13.798)

(2.0552,11.595)

I(pv)

0A

50A

100A

150A




Battery current

Battery voltage

Battery SOC

DC/DC input current

DC output voltage

SOC1=0.3

V=Lopen V=Lclose

Shutdown

Reconnect

Fully charged,

stop charging


power drops.

Charging time

• C1: IC=13.7



• .Options

• RELTOL=0.01

• ABSTOL=1.0u

• ITL4=1000

Time

0s 3s 6s 9s 12s 15s 18s 21s 24s

1 V(out_dc) 2 I(IN)

0V

5.0V

7.5V1

>>

0A

13A

25A

38A

50A2

V(X_U1.SOC)

0V

1.0V


10V

15V1

-100A

0A

100A2

SEL>>SEL>> (8.2938,13.798)

I(pv)

0A

50A

100A

150A




Battery current

Battery voltage

Battery SOC

DC/DC input current

DC output voltage

SOC1=0.07

V=Lclose

Shutdown

Reconnect

Fully charged,

stop charging


power drops.

Charging time

• C1: IC=13.7



• .Options

• RELTOL=0.01

• ABSTOL=1.0u

• ITL4=1000

Time

0s 3s 6s 9s 12s 15s 18s 21s 24s

1 V(out_dc) 2 I(IN)

0V

2.5V

5.0V

7.5V1

0A

50A2

>>

V(X_U1.SOC)

0V

1.0V


10.0V

12.5V

15.0V1

-100A

0A

100A2

SEL>>SEL>>

(21.778,11.600)

(8.2850,13.799)

(4.2247,11.627)

I(pv)

0A

50A

100A

150A

4.3.5 Simulation Result (SOC1=1, IL=100A or 500W load)



Battery current

Battery voltage

Battery SOC

DC/DC input current

DC output voltage

SOC1=100 Fully charged,

stop charging


power drops.

Charging

time

Shutdown

V=Lopen

Shutdown

• C1: IC=13.7



• .Options

• RELTOL=0.01

• ABSTOL=1.0u

• ITL4=1000

V=Lopen V=Lclose

Reconnected

4.3.4 Simulation Result (Example of Conclusion)

The simulation start from midnight(time=0). The system supplies DC load 250W.

• If initial SOC is 100%,

– this system will never shutdown.


– this system will shutdown after 5.749 hours (about 5:45AM.).

– system load will reconnect again at 8:19AM.





– this system will start shutdown.

– this system will reconnect again at 8:18AM (Morning).

• With the PV generated current profile, battery will fully charged in about 5.7 hours.

The simulation start from midnight(time=0). The system supplies DC load 500W.




– this system will shutdown again at 9:47PM.

• With the PV generated current profile, battery will fully charged in about 6.7 hours.


Simulations index

Simulations Folder name

1. PV Ni-MH Battery Charger Circuit..................................................

2. Constant Current PV Ni-MH Battery Charger Circuit.....................

3. PV-Battery System Simulation Circuit (SOC1=1, 250W)...............

4. PV-Battery System Simulation Circuit (SOC1=0.7, 250W)............

5. PV-Battery System Simulation Circuit (SOC1=0.3, 250W)............

6. PV-Battery System Simulation Circuit (SOC1=0.07, 250W)..........

7. PV-Battery System Simulation Circuit (SOC1=1, 500W)...............

charge-sol

charge-sol-const

sol_24h_soc100

sol_24h_soc70

sol_24h_soc30

sol_24h_soc7

sol_24h_soc100_500W


Technology

PV Ni-MH Battery System (Output is DC)