International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 08 Issue: 09 | Sep 2021 www.irjet.net p-ISSN: 2395-0072
© 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 1129
Performance Comparison of 3kW Residential Grid-Connected
Photovoltaic System between Microinverter and String Inverter
Topology using System Advisor Model
Shubham Tiwari
1
, Dr Ruchi Pandey
2
, Mr. Anand Goswami
3
1
Scholar, M. Tech Energy Technology, GGITS Jabalpur, India
2
Professor and H.O.D Electrical and Electronics Engineering, GGITS Jabalpur, India
3
Asst. Professor Electrical and Electronics Engineering, GGITS Jabalpur, India
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Abstract - Grid connected rooftop PV systems are the
most common form of solar energy utilization that helps
home owners to reduce carbon footprint and save money in
utility bills. This project focuses on the design and modelling
of a 3KW residential PV system connected to a 240V single
phase grid.
The purpose of this study was to conduct an independent
experiment on two photovoltaic systems, one with a central
inverter and the other with microinverters, to determine
their comparative performance characteristics.
Both systems have fixed tilt angle and fixed azimuth angle.
In order to analyze the performance of the systems, the
Energy Yield, Performance Ratio, Capacity factor and
Annual Energy have been used. This allowed to obtain a
correct comparison even with different Irradiance values
and different Peak Powers.
In the central inverters, several strings of PV modules are
combined in order to achieve the power required from the
inverter to operate. Strings are connected in parallel and
then these strings are led to the inverter after running
several meters of DC cables.
These cables are often very thick and as a result are very
expensive while at the same time, they add losses to the
overall system. On the other hand, AC cables are much less
expensive and they have fewer losses.
A residential system was designed in SAM using specific
weather data. The simulation results supported the fact that
micro inverters outperform the traditional string inverters
in both shaded and non-shaded conditions.
A significant advantage of Micro Inverters is the avoidance
of shading losses and mismatch among different PV
technologies which consists a great challenge on PV
installations.
This thesis presents experimental data that supports the
conclusion that microinverters can outperform central
inverters in both unshaded and shaded conditions The Micro
Inverter system produced an annual energy of 4916 kWh in
the first year with no shading and 4332 kWh in the first year
with shading losses.
The String Inverter system produced an annual energy of
4763 kWh in the first year with no shading and 4286 kWh in
the first year with shading losses.
Key Words: Inverters, Photovoltaic cells, Photovoltaic
systems, Solar energy, Solar panels.
1.INTRODUCTION
The use of module level power electronic devices (MLPE)
has been proposed to mitigate electrical and thermal
mismatch losses in the field by tracking the maximum
power point of individual modules. In general, MLPE
devices consist of two main categories: micro inverters
and power optimizers. In this paper micro inverters and
boost power optimizers are considered.[1].
The key challenges of partial shading PV models are
therefore to generate accurate yield predictions under
heterogeneous irradiance conditions with reduced
simulation time. In this paper a model is presented that
considers cell shading fractions determined by a 3D model
and applies an irradiance model to determine the effective
irradiance on a partially shaded cell. Moreover, the model
takes into consideration the system architecture and
associated power electronics efficiency losses.[2]
Partial shading is considered as the major challenge faced
by the roof-top PV system that aims to reduce the power
output of the system. All the modules in a string connected
in series carries the same current. Partially shaded
modules which generate less photon current forcefully
carry the current equivalent to the non-shaded modules.
Shaded modules, once reverse biased behave as loads and
deplete the power from non-shaded modules. The absence
of suitable protection for the system can lead to the hot-
spot formation and in the worst scenario will cause
permanent damage [3].
Integration of PV Systems to existing buildings poses
another problem of inevitable partial shading due to
neighbouring structures for different seasons. In standard
PV systems this shading reduces the total power
production to a larger extent than anticipated, leading to
higher capital costs as more modules are required. This
makes the PV systems less appealing to customers. Hence,
the study of partial shading is very important. Also, to
make PV systems reliable for all conditions their
characteristics under different partial shading conditions
needs to be understood.
In the last few years, effects of partial shading on PV
system have been thoroughly studied [4], [5]. Since field