This document describes the components and simulation of a photovoltaic (PV) nickel-metal hydride (Ni-MH) battery system. It includes specifications for Ni-MH battery packs and solar photovoltaic panels. The document outlines simulation circuits and results for charging the batteries from the solar panels under different weather conditions. It also simulates and charts the short-circuit current, battery state of charge, and system output over a 24-hour period to analyze the full PV-battery system performance.

1. Design Kit
PV Ni-MH Battery System (AC Out)
All Rights Reserved Copyright (C) Bee Technologies Corporation 2013 1

2. Contents
Slide #
1. Nickel - Metal Hydride Battery
1.1 Ni-MH Battery Specification................................................................................. 3
1.2 Discharge Time Characteristics........................................................................... 4
1.3 Battery Voltage vs. SOC Discharge Characteristics............................................. 5
1.4 Charge Time Characteristics................................................................................ 6
1.5 Battery Voltage vs. SOC Charge Characteristics................................................. 7
2. Solar Cells
2.1 Solar Cells Specification...................................................................................... 8
2.2 Output Characteristics vs. Incident Solar Radiation............................................. 9
3. Solar Cell Battery Charger......................................................................................... 10
3.1 Concept of Simulation PV Ni-MH Battery Charger Circuit.................................... 11
3.2 PV Ni-MH Battery Charger Circuit........................................................................ 12
3.3 Charging Time Characteristics vs. Weather Condition......................................... 13
3.4 Concept of Simulation PV Ni-MH Battery Charger Circuit + Constant Current..... 14
3.5 Constant Current PV Ni-MH Battery Charger Circuit............................................ 15
3.6 Charging Time Characteristics vs. Weather Condition + Constant Current.......... 16
4. Simulation PV Ni-MH Battery System in 24hr.
4.1 Concept of Simulation PV Ni-MH Battery System in 24hr.................................... 17-18
4.2 Short-Circuit Current vs. Time (24hr.).................................................................. 19
4.3 PV-Battery System Simulation Circuit.................................................................. 20
4.3 PV-Battery System Simulation Result.................................................................. 21-26
Simulations index............................................................................................................ 27
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3. 1.1 Ni-MH Battery Specification
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] 10 Ni-MH cells are
in series.
• Rated Charge................ 0.2C5 [A] ( SoC=100% )
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4. 1.2 Discharge Time Characteristics
17V PARAMETERS:
rate = 0.2
CAh = 177
16V Hi
15V C1 U1 0
1C ( 177A ) IN+ OUT+ 1n + - GIGACELL_10-180
14V 2C ( 354A ) IN- OUT- TSCALE = 3600
G1 0 NS = 1
GVALUE SOC1 = 1
13V 0.2C ( 35.4A ) limit(V(%IN+, %IN-)/0.1m, 0, rate*CAh )
TSCALE=3600
12V 0
0.5C ( 88.5A ) means “Time Scale”
11V (Simulation time :
Real time) is 1:3600
10V
Batteries Pack Model Parameters
9V
NS (number of batteries in series) = 1 Unit (10 Ni-MH cells)
C (capacity) = 177 Ah
8V SOC1 (initial state of charge) = 1 (100%)
TSCALE (time scale) , simulation : real time
7V 1 : 3600s or
0s 1.0s 2.0s 3.0s 4.0s 5.0s 6.0s 1s : 1h
V(HI)
Time
Discharge Rate : 0.2C(35.4A), 0.5C(88.5A), 1C(177A) and 2C(354A)
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5. 1.3 Battery Voltage vs. SOC Discharge Characteristics
10 Ni-MH cells are in series for
total rated current 12V (Each
cell have 1.2V rated voltage).
Measurement Simulation
0.2C, Dch 2.0C, Dch 5.0C, Dch 8.0C, Dch 11C, Dch
17
16
15
Battery Voltage (V)
14
13
12
11
10
9
8
7
0 0.2 0.4 0.6 0.8 1
SOC (%)
• VBAT vs. SOC Discharge Characteristics are compared between measurement data and simulation
data.
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6. 1.4 Charge Time Characteristics
PARAMETERS:
rate = 0.2
CAh = 177
17V G1
GVALUE
Limit(V(%IN+, %IN-)/0.1m, 0, rate*CAh )
16V Hi
OUT+
OUT-
15V 1C ( 177A ) C1 U1 0
1n + - GIGACELL_10-180
IN+
IN-
14V TSCALE = 3600
0 NS = 1
SOC1 = 0
13V 0.2C ( 35.4A ) Vin
18Vdc
12V
0.5C ( 88.5A ) TSCALE=3600
0
means “Time Scale”
11V
(Simulation time :
10V
Real time) is 1:3600
Batteries Pack Model Parameters
9V
NS (number of batteries in series) = 1 Unit (10 Ni-MH cells)
8V C (capacity) = 177 Ah
SOC1 (initial state of charge) = 1 (100%)
7V TSCALE (time scale) , simulation : real time
0s 1.0s 2.0s 3.0s 4.0s 5.0s 1 : 3600s or
V(HI) 1s : 1h
Time
Charge Rate : 0.2C(35.4A), 0.5C(88.5A), and 1C(177A)
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7. 1.5 Battery Voltage vs. SOC Charge Characteristics
Measurement Simulation
0.2C, Ch 2.0C, Ch 3.0C, Ch 5.0C, Ch
17
16
15
Battery Voltage (V)
14
13
12
11
10
9
8
7
0 0.2 0.4 0.6 0.8 1
SOC (%)
• VBAT vs. SOC Charge Characteristics are compared between measurement data and simulation
data.
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8. 2.1 Solar Cells Specification
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]
1482mm
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9. 2.2 Output Characteristics vs. Incident Solar Radiation
STP140D-12/TEA Output Characteristics vs. Incident Solar Radiation
10A
SOL=1
8A
Current (A)
6A
SOL=0.5
4A
+
U1 2A SOL=0.16
STP140D-12TEA
0A
SOL = 1 I(Isense)
150W
SOL=1
Power (W)
100W
Parameter, SOL is added as SOL=0.5
normalized incident radiation,
50W
where SOL=1 for AM1.5 SOL=0.16
conditions SEL>>
0W
0V 5V 10V 15V 20V 25V
V(V1:+)*I(Isense)
V_V1
Voltage (V)
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10. 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
17V
16V
15V
14V
14.2 V
13V
0.2C or 35.4A
12V 11.8 V
11V
10V
9V
8V
7V
0s 1.0s 2.0s 3.0s 4.0s 5.0s
V(HI)
Time
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11. 3.1 Concept of Simulation PV Ni-MH Battery Charger Circuit
Over Voltage
Protection Circuit
Short circuit current ISC
depends on condition: SOL
14.01V Clamp Circuit
Photovoltaic
Ni-MH Battery
Module
STP140D-12/TEA (Suntech) Gigacell 10-180 (Kawasaki)
10 panels (parallel) DC12V (10 cells)
Vmp=17.6V 177Ah
Pmax=1.4kW
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12. 3.2 PV Ni-MH Battery Charger Circuit
D1
PARAMETERS: DMOD
sol = 1
Voch
14.01dc
pv 0
Hi
+ + + + + + -
U6 U5 U4 U3 U2 C1 0
STP140D-12TEA 1n
SOL = {sol}
0
0 0 0 0 0 U1
GIGACELL_10-180
TSCALE = 3600
NS = 1
+ + + + + SOC1 = 0
U11 U10 U9 U8 U7
0 0 0 0 0
• Input value between 0-1 in the “PARAMETERS: sol = ” to set the normalized incident
radiation, where SOL=1 for AM1.5 conditions.
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13. 3.3 Charging Time Characteristics vs. Weather Condition
1.00V
0.75V
0.50V
0.25V sol = 1.00
sol = 0.50
sol = 0.16
0V
0s 1s 2s 3s 4s 5s 6s 7s 8s 9s 10s
V(X_U1.SOC)
Time
• Simulation result shows the charging time for sol = 1, 0.5, and 0.16.
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14. 3.4 Concept of Simulation PV Ni-MH Battery Charger Circuit
+ Constant Current
Over Voltage
Protection Circuit
Short circuit current ISC
depends on condition: SOL
14.01V Clamp Circuit
Constant
Photovoltaic Current
Ni-MH Battery
Module Control
Circuit
STP140D-12/TEA Icharge=0.2C (35.4A) Gigacell 10-180 (Kawasaki)
(Suntech) DC12V (10 cells)
10 panels (parallel) 177Ah
Vmp=17.6V
Pmax=1.4kW
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15. 3.5 Constant Current PV Ni-MH Battery Charger Circuit
D1
PARAMETERS:
PARAMETERS: DMOD
rate = 0.2
sol = 1 CAh = 177
Voch
14.01dc
pv 0
Hi
OUT+
OUT-
+ + + + + + -
U6 U5 U4 U3 U2 C1 0
STP140D-12TEA 1n
SOL = {sol}
IN+
IN-
0
0 0 0 0 0 G1 U1
GVALUE GIGACELL_10-180
Limit(V(%IN+, %IN-)/0.1, 0, rate*CAh) TSCALE = 3600
NS = 1
+ + + + + SOC1 = 0
U11 U10 U9 U8 U7
0 0 0 0 0
• 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.
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16. 3.6 Charging Time Characteristics vs. Weather Condition
(Constant Current)
1.00V
0.75V
0.50V
0.25V sol = 1.00
sol = 0.50
sol = 0.16
0V
0s 1s 2s 3s 4s 5s 6s 7s 8s 9s 10s
V(X_U1.SOC)
Time
• 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.
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17. 4.1 Concept of Simulation PV Ni-MH Battery System in 24hr.
Over Voltage
The model contains 24hr. Protection Circuit
solar power data (example).
14.01V Clamp Circuit
Photovoltaic
Ni-MH Battery
Module
Low-Voltage Gigacell 10-180 (Kawasaki)
STP140D-12/TEA Shutdown DC12V (10 cells)
(Suntech) Circuit Vopen=11. 6(V) 177Ah
10 panels (parallel) Vclose= 13.8(V)
Vmp=17.6V
Pmax=1.4kW
Inverter
Load
(DC/AC)
VIN=8~16V PLOAD=250W
VOUT=100Vac, 50Hz
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18. 4.1 Concept of Simulation PV Ni-MH Battery System in 24hr.
(Reference)
 Kawasaki GigaCell website: http://www.khi.co.jp/gigacell/use/sun.html
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19. 4.2 Short-Circuit Current vs. Time (24hr.)
The model contains
24hr. solar power data
(example).
15A
10A U1
+
STP140D-12TEA_24H_TS3600
5A
0A
0s 1s 2s 3s 4s 5s 6s 7s 8s 9s 10s 12s 14s 16s 18s 20s 22s 24s
I(Isense)
Time
• 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.
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20. 4.3 PV-Battery System Simulation Circuit
Solar cell model
with 24hr. solar D1
power data. DMOD
Voch
14.01Vdc
pv 0
D2
batt
DMOD
+ U6 + U5 + U4 + U3 + U2
C1 0
Low-Voltage Shutdown Circuit 10n + -
STP140D-12TEA_24H_TS3600
VON = 0.7 0
0 0 0 0 0 VOFF = 0.3 E1
RON = 0.01m Ronof f EVALUE
ROFF = 10MEG 100 IF(V(batt1)>V(dchth),5,0) Ronof f 1 U1
+ Lctrl batt1 GIGACELL_10-180
+ OUT+ IN+
+ U11 + U10 + U9 + U8 + U7 C3 TSCALE = 3600
- - OUT- IN- dchth 100
100n Conof f NS = 1
S2 1n SOC1 = 1
0 OUT+ IN+
S IC = 5 Conof f 1
OUT- IN- 100n
PARAMETERS: E2
0 0 0 0 0 Lopen = 11.6 EVALUE
IF( V(lctrl) > 0.25 ,Lopen ,Lclose)
SOC1 value is initial
Lclose = 13.8 0
State Of Charge of
the battery, is set as
Inverter (DC/AC) 70% of full voltage.
Lopen value is load PARAMETERS:
n=1 out_ac
shutdown voltage. PARAMETERS:
IN OUT Pload = 250
Lclose value is load G1 Iomax
Rload
IN+ OUT+ IN+ OUT+ EVout
reconnect voltage IN- OUT- IN- OUT- IN+ OUT+ {100*100/Pload}
GVALUE IN- OUT-
ecal_Iomax
EVALUE EVALUE
0
n*V(%IN+, %IN-)*I(IN)/100
IF( V(Irms)>V(Iomax), V(1VAC)*n*limit(V(%IN+, %IN-),7,17)*I(IN)/(V(Irms)+1u), V(1VAC)*100 )
250(W)
0 Limit( V(%IN+, %IN-)/0.1, 1m, 100*V(Irms)/(n*limit(V(%IN+, %IN-),8,16)) ) 0
Load
abs(I(out)) Rf ilt 1VAC
Irms Vac1
OUT
Cf ilt VOFF = 0
10k
8u VAMPL = 1.414
EC IC = 0.01 FREQ = 50
0 0
 Simulation at 500W load, change Pload from 250(W) to 500(W)
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21. 4.3.1 Simulation Result (SOC1=1, 250W load)
100A
PV generated current
0A
I(PV) PV module charge the battery
16V 100A
1
Battery voltage 2
14V 0A
Battery current 
>>
12V -100A Battery starts to supply current
1 V(batt) 2 I(U1:PLUS) when solar power drops.
1.0V
Battery SOC
Fully charged,
SOC1=1 (100%) stop charging
0V
V(X_U1.SOC)
100VAC output
200V 20.0A
1 2
Inverter input current
0V 17.5A
SEL>>
-200V 15.0A
0s 3s 6s 9s 12s 15s 18s 21s 24s
1 V(out_ac) 2 I(IN) Charging
time Time
 When battery is discharging , current I(U1:PLUS) is minus and when the battery is charging, the current is plus.
• .Options
• C1=10n IC=13.7
• RELTOL=0.01
• Run to time: 24s (24hours in real world)
• ABSTOL=1.0u
• Step size: 0.001s
• ITL4=1000
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22. 4.3.2 Simulation Result (SOC1=0.7, 250W load)
100A
PV generated current
0A
I(PV)
15.0V 100A
Battery 1
voltage 2 (6.9292,11.587)
12.5V 0A (8.4725,13.800)
Battery current V=Lopen
>> V=Lclose Battery starts to supply current
10.0V -100A when solar power drops.
1 V(batt) 2 I(U1:PLUS)
1.0V
SOC1=0.7 Fully charged,
Battery SOC
stop charging
0V
V(X_U1.SOC)
DC output voltage Shutdown
200V 20.0A
1 2
DC/DC input current
Reconnect
0V 17.5A
SEL>>
-200V 15.0A
0s 3s 6s 9s 12s 15s 18s 21s 24s
1 V(out_ac) 2 I(IN)
Time
Charging
time
• .Options
• Run to time: 24s (24hours in real world) • RELTOL=0.01
• Step size: 0.01s • ABSTOL=1.0u
• ITL4=1000
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23. 4.3.3 Simulation Result (SOC1=0.3, 250W load)
100A
PV generated current
0A
I(PV)
15.0V 100A
Battery 1
voltage 2 V=Lopen
12.5V 0A (8.3025,13.800)
Battery current
SEL>> V=Lclose Battery starts to supply current
(2.3577,11.587)
10.0V -100A when solar power drops.
1 V(batt) 2 I(U1:PLUS)
1.0V
Battery SOC Fully charged,
SOC1=0.7 stop charging
0V
V(X_U1.SOC)
DC output voltage
200V 20.0A
1 2
DC/DC input current Shutdown
Reconnect
0V 17.5A
>>
-200V 15.0A
0s 3s 6s 9s 12s 15s 18s 21s 24s
1 V(out_ac) 2 I(IN)
Time
Charging time
• .Options
• Run to time: 24s (24hours in real world) • RELTOL=0.01
• Step size: 0.01s • ABSTOL=1.0u
• ITL4=1000
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24. 4.3.4 Simulation Result (SOC1=0.07, 250W load)
100A
PV generated current
0A
I(PV)
15.0V 100A
Battery 1
voltage 2
12.5V 0A
Battery current (8.3015,13.800)
SEL>> V=Lclose Battery starts to supply current
10.0V -100A when solar power drops.
1 V(batt) 2 I(U1:PLUS)
1.0V
Battery SOC Fully charged,
stop charging
SOC1=0.07
0V
V(X_U1.SOC)
DC output voltage
200V 20.0A
1 2
DC/DC input current Shutdown
Reconnect
0V 17.5A
>>
-200V 15.0A
0s 3s 6s 9s 12s 15s 18s 21s 24s
1 V(out_ac) 2 I(IN)
Time
Charging time
• .Options
• Run to time: 24s (24hours in real world) • RELTOL=0.01
• Step size: 0.01s • ABSTOL=1.0u
• ITL4=1000
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25. 4.3.5 Simulation Result (SOC1=1, 500W load)
100A
PV generated current
0A
I(PV) V=Lclose
V=Lopen V=Lopen
15.0V 100A
Battery 1
voltage 2 (4.8181,11.600) (22.476,11.575)
12.5V 0A
Battery current (8.2935,13.800)
>>
Battery supplies current when solar
10.0V -100A
power drops.
1 V(batt) 2 I(U1:PLUS)
1.0V
Battery SOC Fully charged,
SOC1=100 stop charging
0V
V(X_U1.SOC)
DC output voltage
200V 40A Shutdown Shutdown
1 2
DC/DC input current Reconnected
0V 35A
SEL>>
-200V 30A
0s 3s 6s 9s 12s 15s 18s 21s 24s
1 V(out_ac) 2 I(IN) Charging
time Time
• .Options
• C1=10n IC=13.7
• RELTOL=0.01
• Run to time: 24s (24hours in real world)
• ABSTOL=1.0u
• Step size: 0.001s
• ITL4=1000
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26. 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.
• If initial SOC is 70%,
– this system will shutdown after 6.93 hours (about 6:56AM.).
– system load will reconnect again at 8:28AM.
• If initial SOC is 30%,
– this system will shutdown after 2.36 hours (about 2:21AM.).
– system load will reconnect again at 8:18AM.
• If initial SOC is 7%,
– 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 5.48 hours.
The simulation start from midnight(time=0). The system supplies DC load 500W.
• If initial SOC is 100%,
– this system will shutdown after 4.82 hours (about 4:49AM.).
– system load will reconnect again at 8:18AM.
– this system will shutdown again at 10:29PM.
• With the PV generated current profile, battery will fully charged in about 6.15 hours.
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27. Simulations index
Simulations Folder name
1. PV Ni-MH Battery Charger Circuit.................................................. charge-sol
2. Constant Current PV Ni-MH Battery Charger Circuit..................... charge-sol-const
3. PV-Battery System Simulation Circuit (SOC1=1, 250W)............... sol_24h_soc100
4. PV-Battery System Simulation Circuit (SOC1=0.7, 250W)............ sol_24h_soc70
5. PV-Battery System Simulation Circuit (SOC1=0.3, 250W)............ sol_24h_soc30
6. PV-Battery System Simulation Circuit (SOC1=0.07, 250W).......... sol_24h_soc7
7. PV-Battery System Simulation Circuit (SOC1=1, 500W)............... sol_24h_soc100_500W
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