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6/5/2013
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Eng. Firas Alawneh
PV Systems – Applications and Components
Outline• From Solar Cell to Module to Array
• PV Module Architecture
• PV Module Components
• PV Module Temperature Coefficients
• Hotspot Phenomenon
• Bypass and Blocking Diodes
• Shadowing Effect on PV Modules and Arrays
• PV Module Nameplate
• PV Module Datasheet
• Typical PV Modules Efficiencies
• Types of PV Systems– Standalone “off-grid”
– Grid connected “on-grid”
• PV Mounting Structures
• PV Array Tilt Angle “Inclination” Effect
• PV Array Azimuth “Orientation” Effect 2
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From Solar Cell to Module to Array
PV Module Architecture
4V
12 V Standard
PV Module
(Mainly used for
charging 12 V
battery banks)
IV Curve for a 12 V standard PV module
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PV Module Components
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PV Module Nameplate
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PV Module Datasheet
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Typical PV Modules Efficiencies
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Pmpp (T) = Pmpp (25°C) [ 1 + γPmpp ×(T – 25°C) ]Vmpp (T) = Vmpp (25°C) [ 1 + βVmpp × (T – 25°C) ]Impp (T) = Impp (25°C) [ 1 + αImpp × (T – 25°C) ]Voc (T) = Voc (25°C) [ 1 + βVoc × (T – 25°C) ]Isc (T) = Isc (25°C) [ 1 + αIsc × (T – 25°C) ]
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Excercise
For Sharp PV Module Model No. NU-E245 (J5),
calculate :
1.Voc(+75°C, 1000 W/m2, 1.5 AM)?
2.Voc (-5°C, 1000 W/m2, 1.5 AM)?
3. Isc(+75°C, 1000 W/m2, 1.5 AM)?
4. Isc(-5°C, 1000 W/m2, 1.5 AM)?
5.Pmp (+75°C, 1000 W/m2, 1.5 AM)?
6.Pmp (-5°C, 1000 W/m2, 1.5 AM)?
7.Pmp (+25°C, 500 W/m2, 1.5 AM)?
8.ηmp(+25°C, 1000 W/m2, 1.5 AM)?
9.FF(+25°C, 1000 W/m2, 1.5 AM)?
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The hot spot phenomenon happens when one cell of the panel is shadedwhile the others are illuminated, and when this shaded cell is not able toexhaust its generated power dissipation. The shaded cell behaves as adiode polarized in reverse and generates reverse power PS. The other cellsgenerate a current that flows through the shaded cell and the load RLoad.
Any solar cell has its own critical power dissipation PC that must not beexceeded and depends on its cooling and material structures, its area, itsmaximum operating temperature and ambient temperature. A shaded cellmay be destroyed when its reverse dissipation exceeds PC. This is the hotspot.
The manufacturers usually define a breakdown voltage VC. Its valuedepends on the solar cell technology (poly-silicon or mono-silicon) and themanufacturing process. There is no risk of hot spot while PS < PC.
To eliminate the hot spot phenomenon, a dedicated circuit should bypassthe partially shaded module and eventually it should maintain the operationof the other PV modules creating a path for their current.
Hot spot phenomenon
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Bypass Diodes Inside Junction Box
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The bypass diode principle is to use a diode in reverse paralleling with several solarcells. The bypass diode is blocked when all cells are illuminated, and conductswhen one or several cells are shadowed.
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Building A PV Array (Parallel x Series)
P x S = 2 x 3
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Series and Parallel Connections
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Blocking Diodes
A blocking diode prevents current to flow reversely in PV string (series-connected modules).
A bypass diode prevents hotspot effect in case of shadowing.
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Shadowing Two Series-Connected PV Cells
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Shadowing Two Parallel Strings
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Types of PV Systems
Standalone “off-grid”
Grid-connected “on-grid”
Without storage
With storage
Hybrid Systems directly connected
to the public grid
connected to public grid via house grid
Motors “e.g. pumps”
DC Systems
AC Systems
with wind turbine
with diesel generator
with public grid backup
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Off-grid / Without battery storage / Direct-coupled DC system
PV Array DC Load
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Solar Water Heaters
Off-grid / Without battery storage / Direct-coupled DC system
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Off-grid / Without battery storage / Power-conditioned DC system
PV Array DC Load
DC/DC Power
Conditioning
Unit
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Off-grid / Without battery storage / Power-conditioned DC system
DC Submersible Water Pumping System
PV Array DC/DC Pump Controller DC Submersible Pump
Variable Voltage
(Proportional to Solar Intensity)
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Off-grid / Without battery storage / Power-conditioned AC system
PV Array AC Load
DC/AC Power
Conditioning
Unit
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Off-grid / Without battery storage / Power-conditioned AC system
AC Submersible Water Pumping System
PV Array DC/AC Pump ControllerAC Submersible
Pump
Variable Voltage & Frequency
(Proportional to Solar Intensity)
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Off-grid / With battery storage / DC system
PV Array DC Load
Charge
&
Load
Controller
Battery
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Solar Home Systems & DC Industrial Systems
PV ArrayDC Load
Off-grid / With battery storage / DC system
Battery Bank
Charge & Load Controller
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Off-grid / With battery storage / AC system
PV ArrayCharge
Controller
Battery
DC/AC
Inverter
AC
Load
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Solar Home Systems & AC Industrial Applications
PV Array
AC Load
Off-grid / With battery storage / AC system
Battery Bank
Charge Controller
DC/AC InverterWith fixed voltage & frequency
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Off-grid / With battery storage / Hybrid System
PV ArrayCharge
Controller
Battery
DC/AC
InverterAC
LoadOther
Source
Power
Conditioning
Unit
DC-Coupled
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Hybrid Solar/Wind
PV Array
AC Load
Battery Bank
Charge Controller
Off-grid / With battery storage / Hybrid System
DC/AC Inverter
Wind Turbine
Wind Controller
DC-Coupled
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Off-grid / With battery storage / Hybrid System
PV ArrayPV
Inverter
BatteryDC/AC Inverter
AC
Load
Other
Source
Power
Conditioning
Unit
AC-Coupled
Grid Former
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Inverters
Off-grid / With battery storage / Hybrid System
AC Bus (3-phase)
Hybrid Solar/Wind/Diesel
AC-Coupled
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• The grid is the network of cables by which electricity is
transported from power stations to houses, buildings &
other places.
• A grid connected PV system is linked to this grid or
electrical network. This means that it can deliver the
electricity it produces into the electricity network and
therefore no battery or other storage is needed.
On-grid PV Systems
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On-grid PV Systems
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BLOCK DIAGRAM OF GRID
CONNECTED PV SYSTEMS
Net meteringThe difference between
production-consumption
is measured
Feed-in tariffThe total production of
energy is measured
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SIMPLIFIED DIAGRAM OF A TYPICAL GRID CONNECTED INVERTER
Self-commutated inverter, with
pulse width modulation and line
frequency transformer
Time
Switches S1,S2 cooperate during one half-period - S3,S4 during next half-period
Pulse width modulationPWM
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PV Power Plant
Large PV power plants
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Large on-grid PV power plants
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Large Scale PV Systems
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PV Residential On-grid PV System / Net-metering (Jordan Example)
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PV Mounting Structures
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• Fixed
• Adjustable tilt (season by season)
• Single axis tracking– Horizontal axis
– Inclined axis
– Vertical axis
• Two or Dual Axis Tracking
Tilt or Inclination Angle Effect
46Reference: PVGIS
92
.5%
95
.0%
97
.1%
98
.6%
99
.7%
10
0.0
%
10
0.0
%
99
.3%
98
.1%
96
.2%
93
.9%
91
.0%
87
.5%
83
.5%
79
.0%
74
.2%
68
.8%
63
.3%
57
.2%
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
120.0%
0° 5° 10° 15° 20° 25° 30° 35° 40° 45° 50° 55° 60° 65° 70° 75° 80° 85° 90°
Annual Normalized Energy Yield at Different Tilt Angles in Amman - South Facing
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Azimuth or Orientation Angle Effect
47Reference: PVGIS
10
0.0
%
99
.9%
99
.7%
99
.5%
99
.1%
98
.7%
98
.2%
97
.5%
96
.8%
96
.1%
95
.2%
94
.4%
93
.5%
92
.4%
91
.4%
90
.3%
89
.1%
88
.0%
86
.8%
75.0%
80.0%
85.0%
90.0%
95.0%
100.0%
105.0%
0° ±5° ±10° ±15° ±20° ±25° ±30° ±35° ±40° ±45° ±50° ±55° ±60° ±65° ±70° ±75° ±80° ±85° ±90°
Annual Normlalized Energy Yield at Different Azimuth Angles in Amman
Tilt Angle = 28°
South = 0°
East = -90°
West = 90°
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Fixed PV Mounting Structures
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Adjustable Tilt Angle
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Annual Optimum Tilt (Latitude)
Summer Tilt
Winter Tilt
Effect of Tilt Angle on Monthly Averages of Daily Solar Radiation sums
50Reference: PVGIS
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Horizontal Single Axis Tracking
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Vertical Single Axis Tracking
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Inclined Single Axis Tracking
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Dual Axis Tracking
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Yield Comparison Between Fixed and Tracked PV Mounting Stuctures
55Reference: PVGIS
10
0%
10
0%
10
0%
10
0%
10
0%
10
0%
10
0%
10
0%
10
0%
10
0%
10
0%
10
0%
10
0%
12
2%
12
1%
12
3%
12
6%
13
0% 13
8%
13
5%
13
0%
12
5%
12
3%
12
3%
12
3%
12
7%
11
8%
12
1%
12
5%
12
8%
13
2% 13
9%
13
6%
13
3%
12
8%
12
4%
12
0%
11
9% 1
28
%
12
4%
12
3%
12
5%
12
9% 13
6% 1
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%
14
2%
13
5%
12
8%
12
5%
12
5%
12
5%
13
1%
0%
20%
40%
60%
80%
100%
120%
140%
160%
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Annual Normalized Energy Yield Comparison for Different PV Mounting Structures in Amman
Fixed 28° 1-axis Ver Tilt 50° 1-axis Inc. Tilt 29° 2-axis
Building integrated photovoltaic systems BIPVs
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Building Integrated PV (BIPV)
Thanks
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