1. Performance optimization of Solar PV
plant Through Micro Inverter
Ashish Verma
M.Tech (Energy System)
500022066
University of Petroleum and energy studies

2. Power scenario in India
Growing scenario of Renewable energy
UPES
► Renewable energy accounts for
approximately 12.04% of a total
214.86 GW of power generation
capacity installed in India.
► Demand for power in India has
been increasing due to the rising
population, growing economy, and
changing lifestyles.
► Despite substantial capacity
additions, the power sector is still
in shortage of energy.
► Peak demand shortage averages
around 9%.
► Renewable energy installed
capacity was grown at a healthy
CAGR of 19% over FY07-FY12
Source: MNRE, CEA & Economic survey of India
2012
58%
9%
1%
2%
18%
12%
Coal
Gas
Diesel
Nuclear
Hydro
RES
10.2 12.3 14.4 16.8
20
24.5
FY07 FY08 FY09 FY10 FY11 FY12
Growth of Renewable energy
installed capacity in India
CAGR
19%

3.  India is largest EPC sector in renewable energy
in the World
 Installed capacity of 27.29 GW(up to feb2013)
 various mission and state policies for
enhancing the power generation capacity
through renewable energy(NSM,NBMMP ,Gujrat Solar
policy2009 etc.)
 Target of Renewable energy mix of 15 %
upto2017
 Total installed capacity of Solar PV was 10 MW
before 2009 and now its reached up to 1440MW
(feb2013)
 Expected CAGR of installed capacity of Solar
PV is 47 % during the 2011-16
Source :EFYtimes, MNRE,PV- Magazine, NAPCC
Break Up of Renewable Energy
Growth rate of Solar PV UPES
68.27%
13.01%
4.63%
8.43%
0.35% 5.30%
Grid Interactive Installed
capacity (In MW)
Wind
Small Hydro
power
Biomass Power
Bagasse
Cogeneration
Waste to power
Solar PV

4. Different type of Solar PV plant and his component UPES
Grid Connected System & Component
1. Module
2. Inverter
3. Transformer
4. Distribution panel
Off grid System & Component
1. Module
2. PCU ( Charger controller /Inverter )
3. Battery
4. Distribution Panel
Decentralized System
Suitable for where grid connectivity is poor or grid is not viable
Best option for Rural Electrification

5.  Grid connected Solar PV plant cost is 8
Cr/MWp
 Land according to technology used
(Crystalline & Thin film)
 Highest cost sharing by PV module is
around 43%
Source: CERC
Break up Cost of Solar PV plant UPES
43%
7%2%
12%
13%
13%
10%
% Sharing of Cost/MW
Module
PCU
Land Cost
Civil and General
Work
Mounting Structure
Evacuation cost up to
Inter connection
point
IDC & Contingency
cost

6.  CUF
which is ratio of actual energy produced from the plant to maximum possible output
during the year
 Radiation of the Site -
Responsible of energy generation through solar PV
Primary requirement for design of power plant
Data me be instant(Irradiance) or integrated(irradiation )
Comparable result found the inaccuracy of 20-25%
 Losses in PV system
Which cause the power actually delivered to the grid to be lower than the power
produced from PV module
Cable loss
Power Inverter
Dust on the Module surface
Ambient temperature
Varying insolation level
Performance parameter of Solar PV plant
UPES

7. Reflection loss
data show that the module faced toward the equator with tilt angle of latitude ,yearly
reflection losses is 1 % relative to STC
Soiling Loss
Occur due to dust and dirt particles
Losses are generally 1%
Reduce the power capability
Mismatch Effect
Losses due to series and parallel connection of Module
Module don’t have identical property
MPPT Loss
Extract the max power from Solar PV
Inverter Efficiency
Stand alone ,Grid tied
Efficiency measure how well it convert the dc voltage into AC voltage
Efficiency of 95-98 %
Less efficiency at low power

8.  Temperature and climate condition
Power decrease according to temperature coefficient
Typical value for Crystalline module is -0.4- 0.45%/ C
Typical value for thin film module is -0.24-0.25%/ C
 Design parameter of Plant
Minimization of ohmic losses
Selection of efficient transformer and Inverter
Mounting position –proper air ventilation required
Inclination angle –max radiation can be obtained by optimum tilt angle which is
determine by the latitude of location
 Module power degradation due to ageing
-0.50% reduction of power Per year
90% of the max power up to 10 years and 80% of the max power next 15 years

9.  Ensure continuous and reliable operation
 Generating maximum energy
 Maximize the economic performance
 Ensure better PR
 Life expectancy
 Long term commercial utilization of plant
Need of optimization and evaluation of the Performance ? UPES

10.  It build into or attached to each PV module
 Each micro inverter convert Dc from each module to AC ,ready for grid connection
directly
 Allow Each module to be an independent ,standalone , Solar AC grid connected
system with optimized energy production output
 Less space for installation
 No handling to high DC voltage
 No Issue of single point failure
 Life is more 20-30 % than String inverter
 Market Growth is around $14.8Billion*
Source: Bloomberg Energy ,NREL, Enphase
Micro Inverter -Technology

11.  Activation Process
 Array Gun
 Center feed – separate the individual branch circuit current for protection with
OCPD(over current protection device )
 Communication domain
 Engage cable – connecting the Micro Inverter
 LCF – when more than one communication domain is installed ,for reducing the
noise level
 Micro Inverter- Inverter automatic detect the utility scale voltage and export power
the utility services , connected with CB
 Micro inverter Sub panel
 PLC
 Transformer –use to connect the commercial PV project to utility grid
Micro Inverter Component

12. Micro inverter operate similarly to central inverter System
Connected on each individually module
Handle much less power than central inverter
Yes ,Micro inverter are better option for optimization
Improve the energy harvest
Increase reliability
Simplify design ,installation
Better monitoring of Individuals
Dynamic MPPT efficiency is around 99.3%
Integrated with PLC
Micro Inverter
Is micro inverter best option to optimize the performance ? UPES

13. Connection of Micro inverter Integrated with Solar PV Module UPES
Source :Enphase Energy

14.  Deliver design flexibility
 Integrated intelligence
24/7 monitoring analysis
Quick and simple design ,installation and management
 Increase energy harvest
Due to minimization of system losses due to DC-AC conversion
 Cost effective
Cost is 10-12% high comparable to Central or String Inverter
Energy production 18-20% high , so cost effectiveness is justified
 Limitless scalability
Include main panel board of PV load center that feeds multiple micro inverter sub
panel distributed across the system
Benefits of Micro Inverter over other Inverter

15.  Isolating Communication devices
Reduce the communication noise
Better individual Monitoring
 Reliable
System availability greater than 99.8%
No single point failure of system
Safe
Low voltage DC
Reduce fire risk
Source: Enphase energy, NREL

16. PV module with String & Central Inverter
PV module with Micro Inverter
Micro Inverter V/S String ,Central Inverter UPES

17.  Buyers wants to know what would be the PBP of investment
 Saving and PBP is vary according to location
 Dependent on various factor like
cost of electricity from the grid
Feed in Tariff
Subsidy
Capital cost
Unpredictable factor , like radiation that affect the amount generation of electricity
LCOE (Levelelized cost of Electricity) – best option to comparing the
lifetime system cost with total power harvested over the period of time help to
determine the ROI
Economics behind installing Micro Inverter UPES

18. LCOE takes account of
1. Capital Cost- module cost , cost of power conversion electronics, Installation
2. Power harvesting –the total power harvested from the system ,through its life
time and monetary value of each harvested kWh ,determine the financial return
3. Operation & Maintenance – Directly proportional to the system reliability ,if
it is difficult to locate the source of problem ,the time spent on locating the fault will
increase the cost
Low LCOE show that RE power production is cheep and close to achieving GRID parity
Power optimizer are also used for extracting the max power from Module ,but cost is
increase $200 per module and need of central inverter same

19. Capital Cost :
System Rating -7kWp
Module cost per Watt-$2 ($14,000)
String Inverter Cost per Watt - $0.5($3,500) Micro Inverter Cost per Watt- $0.75($5,250)
Total =$17,500 Total=$19,250
Cost is 10% more than String inverter
Installation Cost
No high voltage DC switch and wire
No need to allocate area for inverter in building
According to market survey installation cost for String inverter is $16,500 and for Micro
inverter is $12,500 for 7kWp plant
Offer saving of 24% in installation cost
Enecsys Case Study : Architecture Cost Evaluation

20.  PV Evaluation Lab (PVEL), in association with NREL ,recently performed a series of
field test to measure the shade impact on solar array output.
 Solar Micro inverter shows the higher output than a string inverter in certain cases
 Perform in Light ,Medium and Highly shade – 4%,8%,12% increased energy harvested
by Micro Inverter
 Solar power electronics ,Inverter ,Micro Inverter ,Power converter have a range of
obtaining Max power curve
 NREL developed different type of standard test procedure for simulating PV
performance under shade
Source: NREL , PVEL, Enphase energy
Shade impact On Power Generation Through Solar PV
Experimental Case study - String & Micro inverter

21. Characteristics Curve of System with Shade effect
Source: NREL , PVEL, Enphase energy

22. Adopted Methodology
Performance tested on two identical 8kWp Array
One connected with String inverter and another is with Micro Inverter
Tested under different 78 shaded test condition
Semi Transparent mess in Module

23.  Mesh with transparency of 36%
 Shade configuration time is around 20 Minutes
 Performance is measured with the RGM (Revenue grade meter )
Result
 Micro Inverter perform better in shading
 String inverter stuck in the a local MPP causing current limited operation of the
system
 NREL’s result show that the approximately 50% of the energy lost due to shading by
string inverter ,specially in light shade condition
 Micro inverter increase the harvested energy 4%,8% and 12% in light , medium and
high shade condition

24. Result Summary with Graph
Inverter output V/S Shade area

25. Question & Answers
Thank You….