PV SYSTEMS, COMPONENTS DEVICES AND APPLICATIONS

1. Prabir Kumar Dash
Scientist
Solar Energy Centre
prabir.dash@nic.in

2.  Solar energy is the most abundant source of primary
energy ( 7.2 x 1018 kJ/day)
 There are Two methods of harnessing solar energy
( photovoltaic & thermal)
 Method Of Direct Conversion Of Sunlight To
Electricity Using Solid State Devices Is Called
Photovoltaic.
 Generation Is Clean, Quite, and Reliable
 Requires minimum operation & maintenance .
 Some cases it is the cheapest option of meeting the
energy requirement.

3.  A solid state device which produces current
when certain range radiation spectrum falls on
it.
 The operation consists of three steps.
1. Absorption of radiation ( pair production)
2. Charge separation
3. Collection ( flow of electron in the load
circuit)
 Various technology devices available are
Crystalline Si, a – Si, thin film technologies like
CdTe, CIGS, GaAs, DSSC and organic cells.

5. THEORITICAL EFFICIENCY ~BAND
GAP ENERGY OF MATERIAL

7. 1st generation
Silicon wafer
2nd generation
Thin film on glass
3rd generation
Thin film on
flexible foil
4th generation
Organic cells.
Absorber thickness
≤ 200µm
Absorber thickness
≤ 3µm
Absorber thickness
≤ 3µm
Absorber thickness
≤ 3µm
Limited by wafer
size
Large area
deposition
Large area
deposition
Large area printing
Rigid Rigid flexible flexible
Mature Mature Emerging R & D stage
Limited cost
reduction potential
Limited cost
reduction potential
Low cost potential lowest cost
potential

8.  Solar cell is the basic building block
of any Solar PV system.

10.  Open circuit voltage
 Short circuit current
 Maximum/peak power
 Voltage at maximum power point
 Current at maximum power point
 Fill factor
 Series resistance
 Shunt resistance
The current ~voltage characteristics are measured at Standard Test
condition (STC) defined by three parameters
1. Temperature ( 25 0 C), 2. Irradiance (1000 W/M2 ), 3. Spectrum (1.5G AM)

11. Inverse of slop at Voc is called series resistance Rs
Inverse of slop at Isc is called shunt resistance Rsh

12.  It is the ratio between power output to power
input.
 Out put power is the power at maximum
power point.
 The input power can be calculated by
multiplying Irradiance with area of the PV
device.
 For commercially available Crystalline Si cells
the efficiency is around 14-19%
 For thin film modules it is 6-10%

13.  Positive temperature coefficient of current-α
 Negative temperature coefficient of voltage-β
 Negative temperature coefficient of power-γ.

14. • Current is directly proportional to Irradiance
•Voltage has a logarithmic dependence on irradiance.

15.  Effect of spectrum depends on the material
characteristics.
 The defining parameter is called spectral
response: Amount of current produced per
incident power in watt

16.  No of cells connected in series/parallel to
produce workable current/voltage.

18.  All cells must be checked for micro cracks or
any other defects.
 Cells to be connected in series must be current
matched
 Cells to be connected in parallel must be
voltage matched.
 Grid contacts should be uniform and optimized
to have minimum contact resistance.
 The lamination must not have any air bubble or
pores for moisture ingression.

19.  A bypass diode is connected parallel to the cell
string to prevent reverse biasing of the module
at partial/complete shading of the PV module.
 A blocking diode is connected in series to the
PV module so as to prevent back flow of
current in from battery bank to Module at
night.
 Rating of the diodes is such that it can carry a
current of short circuit current at a temperature
of 80 0 C for 5 hours.

20. Solarcell
Area 100 cm²
Voltage: 0,5 Volt
Current 3,0 Ampere
Power 1,5 Watt
Solarmodule
36 Solar cells
Voltage 18 Volt (36 * 0,5 V)
current: 3 Ampere
Power: 54 Watt (36 * 1,5 W)
Solar generator
18 Solarmodule
voltage: 108 Volt (6 * 18 V)
current 9 Ampere (3 * 3 A)
power: 972 Watt (18 * 54 W)
Typical values for standard
conditions:
•radiation G = 1000 W/m²
•Cell temperature T= 25°C
•Air Mass AM = 1.5 G

21.  Integrated assembly of PV modules and
components to produce power for a particular
service.
 May be for electricity generation, pumping
water or feeding power to lighting or any
mechanical work.
 Because of the modular characteristics, PV
systems can be designed to meet the energy
demand from few watt to megawatt.
 Most favored for remote application where
grid extension is not possible.
 Can be designed for both AC and DC load.

22.  Can be classified according to their component
configurations, and how the equipment is
connected to other power sources.
 Stand alone systems
 Grid interactive systems
 Hybrid systems

23. GRID CONNECTED SYSTEMS STAND ALONE PV SYSTEMS

25.  PV ARRAY
 PANEL MOUNTING
STRUCTURE
 COMBINER BOX
 CHARGE CONTROLLER
 BATTERY BANK
 INVERTER
 AC AND DC DISCONNECTS
 MISCELLANEOUS
COMPONENTS(Cables,
connectors, conduit and
brackets)
 LOADS

26.  A number of modules assembled
together with support structure
is called an array.
 Individual modules produce
electric current and voltage that
depends upon the specific
module
 To have the desired voltage and
current input we have to connect
several modules in
parallel/series
 For parallel connection modules
must be voltage matched.
 For series connection modules
must be current matched

27.  To hold the module in a required direction without
undue stress.
 Support structures to affix the array to either a
roof, a pole, or the ground
 Must be unobstructed to get radiation & accessible
for cleaning
 Basically two types - fixed and sun tracking type
 For fixed type panel mounting must be
perpendicular to the noon day sun.
 For tracking sun type provision is there for single
or double axis rotational movement.
 Material & mechanical strength of the structure
must be taken into account for design.

28.  There are following alternatives
• Fixed tilt
• Seasonal tilt
o Winter tilt (O, N, D, J, F, M)
o Summer tilt (A, M, J, J, A, S)
• Single axis tracking (Fixed tilt)
• Dual axis tracking
 Seasonal tilt is most preferred after fixed tilt
 Trackers pose following challenges
• Moving part and hence less reliable
• Bankability
• Higher area
• Additional capital cost
• Higher O&M Cost

32.  A solar combiner box combines several solar
panels into one dc output to be connected to
the charge controller

33.  A charge controller regulates the amount
of current fed into a Battery bank from
PV array
 Their main function is to prevent overcharging
and deep discharge of the batteries, but charge
controllers also block battery bank current from
leaking back into the PV array at night or on
cloudy days, draining the battery bank.
 It can be done with a normal ON/OFF switch
which will connect/disconnect at the desired
voltage of the battery to the PV array.
 The two main types are PWM (pulse width
modulated) and MPPT ( Tracking)

34.  PWM is a way of digitally encoding analogue
signal levels
 Pulse width is modulated with the battery
voltage to optimize the charging process.

35.  MPPT Match The Maximum Power Point With
The Load Voltage.
 Basically receives power at the maximum
power point voltage and delivers at load
voltage.
 Can be achieved by the following three
methods
1. Perturb & measure: adjust voltage towards
maximum power
2. Incremental conductance: finding value of V
for dP/dV =0
3. Constant voltage : set the voltage at 0.76 Voc

36.  It Is An Important Component For Stand Alone PV Systems.
 Chemically stores electrical energy in the daytime & delivers
power when required and renewable source is not available.
 A large capacity has to be stored with slow rate of discharge.
 Various technologies options are available (Lead-Acid, Ni-Cd,
NiMH, Li- ion etc).
 Flooded lead –acid batteries are very common and cheap, hence
widely used for this application
 During sun-less days, batteries are discharged but not charged.
These conditions result in battery operating in Partial State of
Charge (PSOC) Cycling and Deep cycling. Also, solar systems are
installed in open atmosphere exposing the batteries to extreme
Temperatures. Other lead acid batteries fail in such conditions due
to sulphation, stratification, corrosion and plate shedding.
Moreover, remote solar installations make water top-up difficult
and costs money

37.  To meet the above requirement Tubular VRLA
batteries are better choice.
 Other options are AGM (absorbent glass mat)
& Gel type batteries.
 Specified with capacity & voltage .
 Characterized By The following parameters.
1. Number Of Charge Discharge Cycles
2. Depth Of Discharge.
3. Self discharge
4. Charge efficiency

39.  No of batteries are connected in series/ parallel
to store enough charge to meet the autonomy
condition of the PV system.
 When connected in series the net voltage is the
algebraic sum of individual voltage of a cell.
 When connected in parallel charge/discharge
current get added up.
 It is always preferred to have series connected
battery bank for better performance.

40. Battery bank of 10kW Roof top power plant at SEC

41.  A solar inverter
Converts the variable
DC to AC of desired
frequency and phase.
 Specified by Rating (
kVA/kW), Input
voltage, output
current/voltage,
Efficiency etc.
 Can be classified into
two types
1. Grid-capable
2. Standalone Units.

42.  Converts DC power from the solar array to AC
to be fed in to the utility grid.
 Gives Sine wave out put.
 Match the phase with the grid.
 Must have anti-Islanding protection
 Normally have higher input voltage: More than
120 volts.

43.  Converts DC power from the battery to AC for
running AC loads.
 Both sine and quasi sine wave out put are
available . Selection must be done as per the
load requirement.
 Normally operate at low input voltage at 12V,
24V, or 48 V.
 Both single phase and three phase out put are
available.
 Efficiency: ≥ 90 %

44.  AC/DC disconnect
allows you to isolate the
system
 For safety and
maintenance of the
system
 Rating of the switches as
per system requirement

45.  These Are Normal Electrical Components
Commonly Used For Electrical Wiring.
 Connecting Cables
 Connectors
 Conduit and brackets

46.  The power consuming component
 Two types of loads (AC & DC)
 May be thermal, luminar and mechanical
device.
 AC loads may be inductive, capacitive or
resistive load
 Type of load and hence the power factor must
be taken into account on the design stage.

47.  LED based
3 -5 Wp module, 12 V, 5- 7 Ah @ 20C, SMF Lead-
Acid/ NiMH with 75 % DoD battery.
Duty cycle: 4 Hrs a day
Autonomy: 3 days
Minimum Efficiency of electronics: 85%
Light out put as follows:
Distance from centre Lux level
1 feet 105
2 feet 32
3 feet 16
4 feet 9.5
5 feet 6.5

48.  Light Source : White Light Emitting Diode (W-LED)
 Light Out put : White colour (colour temperature 55000-65000K)
Minimum 15 LUX when measured at the periphery of 2.5 meter
diameter from a height of 2.5 meter. At any point within area of
2.5mtr diameter periphery the light level should not be more than
three times of the periphery value. The illumination should be
uniform without dark Bands or abrupt variations and soothing to
the eyes. Higher output would be preferred.
 Mounting of light: Wall or ceiling
 Electronics : Min 85 % efficiency
 Average duty cycle: 5 hours a day
 Autonomy: 3 days (Minimum 12 operating hours per permissible
discharge

49.  Model - 1
One White LED lumaniare
6Wp Module at STC @ 16.4V, battery: SMF type 12 V, 7
Ah @ C/20 with maximum 75 % DoD.
 Model - 2
Two White LED lumaniare
12Wp Module at STC @ 16.4V, battery: VRLA type 12 V, 12
Ah @ C/20 with maximum 75 % DoD.
 Model – 3 :
Two White LED luminaries and one DC fan of wattage up to
10 W
24Wp Module at STC @ 16.4V, battery: VRLA type 12 V, 20
Ah @ C/20 with maximum 75 % DoD.
 Model - 4
Four White LED lumaniare
12Wp Module at STC @ 16.4V, battery: VRLA type 12 V, 12
Ah @ C/20 with maximum 75 % DoD
THERE ARE FOUR MODELS OF HOME LIGHTING SYSTEMS WITH
FOLLOWING DETAILS.

50.  Light Source: White Light Emitting Diode (W-LED)
 Light Out put: White colour (colour temperature 55000-65000K)
minimum 15 LUX when measured at the periphery of 4 meter
diameter from a height of 4 meter. The illumination should be
uniform without dark bands or abrupt variations, and soothing to
the eye. Higher light output will be preferred.
 Mounting of light: Minimum 4 metre pole mounted
 PV Module : 40 Wp under STC, measured at 16.4 V at load.
Module Voc minimum of 21V
 Battery: Tubular Lead acid Flooded or Tubular GEL / AGM
VRLA , 12 V- 40 AH @ C/10, Max DoD 75%
 Electronics Efficiency: Min 85% total
 Duty cycle : Dusk to dawn
 Autonomy : 3 days (Minimum 42 operating hours per permissible
discharge

51.  Rural sector (village lightening, water
pumping, community light & TV, Telephone
and health centre)
 Communication(very low transmitter,
microwave repeater)
 Road & railways (signaling, panel interlocks,
station lightning, track circuits)
 Others (battery charging, water purifier,
warning light, cold storage, offshore platform
lightening etc.)

52. SOLAR LANTERN
SOLAR HOME
LIGHTING
SYSTEM
SOLAR STREET
LIGHTING
SYSTEM
BILL BOARD
LIGHTING

53. SOLAR LANTERN

54. SOLAR LIGHT IN A TRIBAL VILLAGE HOUSEHOLD

55. SOLAR STREET LIGHT IN A VILLAGE IN BASTAR

56. SOLAR POWERED TV IN A VILLAGE

57. SOLAR SYSTEM FOR
MICROWAVE REPEATER SYSTEM

58. SOLAR SYSTEM FOR OFF
SHORE PLATFORM

59. SATELLITE EARTH STATION AT POOH

61.  Participated in world solar challenge, december
2011 in Australia.
 Total distance 3000 kM
 Top speed of 85 kM/ Hr
 Powered by 1 kW Multi
crystalline PV Panel
 48 V & 40 Ah, Li Fe PO4 batteries.
 MPPT charge controller.
 High power brush less DC hub Motor

62. Solar powered Aero plane.

63.  All cost comparative statements between different sources
of energy use the following formula for calculating energy
cost.
Per kWh cost = (Total Construction Cost + Production Cost +
Decommissioning Cost)/(MW rating X 1000 X Useful Life X
Capacity Factor X 8760)
 Third party cost imposed by the industry never taken into
account.
 Considering the decreasing trend of PV cost. Moore’s Law
can be applied to it at 7% per year ( adjusted to inflation).
 If we calculate the cost of power from thermal PP, taking
into account health hazard & other environmental & social
issues, it is quite possible we have already passed the
tipping point.
 Paul Krugman has already advocated this.
 The extern E-Pol project report also gives the external cost
for thermal PP around 4-8 euro cents/KWh

64. ?