International Journal of Engineering Trends and Technology- Volume4Issue3- 2013
High reliable and advanced cost effective
solar production with stable organization
Ramakrishna Bhagawan.P1, A.PRAVIN2, T.V.JANARDHANA RAO3, DR.N.S.MURTHI SARMA4
1
M.Tech Student, ,2ASSOC.PROF
3
PROFESSOR,4PROFESSOR
ABSTRACT: When connecting to the grid
INTRODUCTION: Depleting non renewable
isolation plays a key factor in selection of
sources have raised interest in sourcing power
power topology and system design. Isolation
from renewable and cleaner power sources. A
requirements depend on the type of PV Panel
large component of energy expended in the
used and the local grid codes. Isolation can be
world is used by industries and houses that are
at the grid connection stage, which uses low
connected to the electrical grid. Thus attempts
frequency transformer. In this case both the
are being made to raise the percentage of
boost and the inverter stages may be controlled
energy sourced from renewable sources in the
using a single microcontroller. However, low
grid.
frequency transformers are heavy, bulky and
considered quintessential factor in increasing
lossy. Therefore cannot be used for low power
this percentage due to ubiquitous nature of
PV inverters. Here, this project implements PV
solar power and absence of any moving parts
inverter topology with isolation at high
and hence extended life time. Also as PV
frequency. This project discusses the design of
panels can be installed in a distributed way
a smart
grid-enabled renewable energy node
close to where the energy is consumed for
using
a
example
heterogeneous
microcontroller.
Real-time
dual
control
core
Photovoltaic (PV) energy sources are
in
residential,
it
eliminates
of
transmission losses. Feeding power into the
extracting the energy from the renewable
grid has its unique set of challenges, to name a
source is done on one core and the Ethernet
few: the PV panel is a DC source hence a PV
server is run on the other core. Hardware
system needs to convert this into AC and feed
design for the energy node to extract maximum
into the grid. Therefore inverter technology is
power from the solar panel is discussed along
quintessential for success of PV inverters. For
with communication interface.
Software
the inverter to feed power into the grid it must
design and integration challenges for control
maintain a DC bus greater than the max
and communication are presented and the
instantaneous voltage of the grid, thus a boost
solution using dual core microcontroller
stage may be required. Also as PV shows a
illustrated.
unique V vs I characteristics the installation
KEYWORDS: Smart Grid, Heterogeneous,
must make sure that it operates at the
Isolation, Central Inverter, renewable energy,
maximum power point (MPP) of this curve. In
topology, Inverter, reliability, stability
addition the current that the inverter feeds into
the grid must be clean and in phase with the
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International Journal of Engineering Trends and Technology- Volume4Issue3- 2013
grid. Several disturbances exist on the grid,
electric
like voltage swells and dips, phase jumps and
substation and distribution automation, is now
noise from appliances running etc, thus the
included in the general concept of the smart
system must be able to estimate the phase of
grid, but additional capabilities are evolving as
the grid accurately along with rejecting these
well.
disturbances on the grid.
SOLAR ENERGY: Solar energy, radiant
SMART GRID: A smart grid is an electrical
light and heat from the sun, has been harnessed
grid that uses information and communications
by humans since ancient times using a range of
technology to gather and act on information,
ever-evolving
such as information about the behaviors of
technologies include solar heating, solar
suppliers and consumers, in an automated
photovoltaic, solar thermal electricity and solar
fashion to improve the efficiency, reliability,
architecture, which can make considerable
economics, and sustainability of the production
contributions to solving some of the most
and distribution of electricity.
urgent problems the world now faces. Solar
Origin of the term "smart grid": The term
technologies are broadly characterized as
smart grid has been in use since at least 2005,
either passive solar or active solar depending
when it appeared in the article "Toward A
on the way they capture, convert and distribute
Smart Grid" by Amin and Wollenberg. The
solar energy. Active solar techniques include
term had been used previously and may date as
the use of photovoltaic panels and solar
far back as 1998.[citation needed] There are
thermal collectors to harness the energy.
many smart grid definitions, some functional,
Passive solar techniques ninclude orienting a
some
benefits-
building to the Sun, The input current pv I is
to
most
sensed before the input capacitance along with
definitions is the application of digital
the panel voltage pv V . These two values are
processing and communications to the power
then used by the MPPT algorithm. The MPPT
grid, making data flow and information
is realized using Increasing the current
management central to the smart grid. Various
reference of the boost, i.e. current drawn
capabilities result from the deeply integrated
through the boost loads the panel and hence
use of digital technology with power grids, and
results in the panel output voltage drop.
integration of the new grid information flows
Therefore the sign for the outer voltage
into utility processes and systems is one of the
compensator reference and feedback are
key issues in the design of smart grids. Electric
reversed. an outer voltage loop that regulates
utilities now find themselves making three
the input voltage to the boost stage i.e. the
classes of transformations: improvement of
output of the panel, by modulating the current
infrastructure, called the strong grid in China;
reference for an inner current loop of the boost
addition of the digital layer, which is the
stage
essence of the smart grid; and business process
thermal mass or light dispersing properties,
transformation, necessary to capitalize on the
and designing spaces that naturally circulate
investments in smart technology. Much of the
air.
technological,
oriented.
A
and
common
some
element
grid
modernization,
technologies.
selecting materials
especially
Solar
with
energy
favorable
modernization work that has been going on in
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International Journal of Engineering Trends and Technology- Volume4Issue3- 2013
A common use of the term voltage converter is
direct current—and distinguish it from low
for a device that allows appliances made for
voltage (50–1000 V AC or 120–1500 V DC)
the mains voltage of one geographical region
and extra-low voltage (<50 V AC or <120 V
to operate in an area with different voltage.
DC) circuits. This is in the context of building
Such a device may be called a voltage
wiring and the safety of electrical apparatus.
converter, power converter, travel adapter, etc.
In the United States 2005 National Electrical
Most single phase alternating-current electrical
Code (NEC), high voltage is any voltage over
outlets in the world supply power at 210–
600 V (article 490.2). British Standard BS
240 V or at 100–120 V. A transformer or
7671:2008 defines high voltage as any voltage
autotransformer
used;
difference between conductors that is higher
(auto)transformers are inherently reversible, so
than 1000 V AC or 1500 V ripple-free DC, or
the same transformer can be used to step the
any voltage difference between a conductor
voltage up, or step it down by the same ratio.
and Earth that is higher than 600 V AC or
Lighter and smaller devices can be made using
900 V ripple-free DC.
electronic circuitry; reducing the voltage
Electricians may only be licensed for particular
electronically is simpler and cheaper than
voltage classes, in some jurisdictions. [1] For
increasing
travel
example, an electrical license for a specialized
adapters suitable for low-power devices such
sub-trade such as installation of HVAC
as electric shavers, but not, say, hairdriers, are
systems, fire alarm systems, closed circuit
available; travel adapters usually include plug-
television systems may be authorized to install
end adapters for the different standards used in
systems energized up to only 30 volts between
different countries. A transformer would be
conductors, and may not be permitted to work
used for higher power. The term high voltage
on mains-voltage circuits. The general public
usually means electrical energy at voltages
may consider household mains circuits (100–
high enough to inflict harm or death upon
250 V AC), which carry the highest voltages
living things. Equipment and conductors that
they normally encounter, to be high voltage.
it.
can
Small,
be
inexpensive,
carry high voltage warrant particular safety
requirements
and
procedures.
In
certain
Choosing a converter:
industries, high voltage means voltage above a
A converter to drive equipment should be
particular threshold (see below). High voltage
specified to supply at least the actual watts or
is used in electrical power distribution, in
amperes used by the equipment; this is usually
cathode ray tubes, to generate X-rays and
stated on a label on the equipment. A converter
particle beams, to demonstrate arcing, for
of higher rating is safe to use. Some equipment
ignition, in photomultiplier tubes, and in high
uses more power or current at startup; a 20%
power amplifier vacuum tubes and other
margin is usually adequate, although it may be
industrial and scientific applications. The
included in the rated figure
International Electrotechnical Commission and
HARDWARE PLATFORM: Below drawn
its national counterparts (IET, IEEE, VDE,
Fig1 block implements the diagram of the
etc.) define high voltage as above 1000 V for
hardware platform for PV inverter. The board
alternating current, and at least 1500 V for
is designed to interface with a high watt solar
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International Journal of Engineering Trends and Technology- Volume4Issue3- 2013
panel
and
the
power
stages
designed
hardware circuitry. Controlling of all home
accordingly. The power rating is kept low so
appliances are done using GSM and internet.
that new users can work with the board to
One special GUI is created for monitoring all
experiment with PV systems. A high efficient
devices, which works with solar energy
and more reliable hardware platform is
generated from solar panel.
designed for controlling high frequency grids
with out using external components and extra
Fig1: Controlling unit
Fig2: Inverter circuit diagram
PV Panels have a unique V vs I characteristics,
the board can be used to change the look up
to
quick
table curves for the panel emulator. PV
development of PV systems, a low cost panel
emulator control scheme is shown in above
emulator is integrated on the board. The panel
Fig1. The control of the PV panel emulator is
emulator is based on a DC-DC stage which is
kept separate from the control of the power
operated in voltage mode. As PV is a light
processing stages of the PV inverter. Fig 2
dependent source the light sensor integrated on
shows the detail of the power stages present on
enable
understanding
and
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International Journal of Engineering Trends and Technology- Volume4Issue3- 2013
the board along with sense signals. The board
being used for safety applications. With the
follows a macro based approach and the input
above discussion, unique challenges of control
and output of each power stage is kept in form
and communication in design of PV inverters
of connectors, this enables easy debug of each
for smart grid have become clear. As the
stage. Also, the blocks can be connected in
switching frequencies for the power
different fashions to implement different PV
being controlled rises, along with added
systems.
functionality using a single controller (single
HETEROGENEOUS DUAL CORE MCU:
cpu) for both control and
Automotive SoCs have traditionally been
becomes complicated. Addition of Ethernet
single core, since not much computational
style application layers adds more complexity
work or high end applications were targeted on
to the system design. A typical way of solving
them. Automotives were simpler, so were the
this is to use a two chip solution where one
applications and so were the SoCs. As more
chip handles the control and the other
and more electronics made room in the
communication. Having a two chip solution
automotives, the complexity of the SoCs kept
increases the complexity of the board and the
on increasing. Now the focus is to have most
design along with increasing the total cost.
of the automotive under electronic control.
The grid current and the inverter current to be
stages
communications
in phase, this implies power from the grid and
High end automotives produced these days
the solar explorer load is summed at the load.
provide features like electronic stability control
Thus the grid current changes phase, showing
(ESC),
current feed into the grid from the board.
traction
control
system
(TCS),
advanced driver assistance systems (ADAS)
etc. These features require complex SoCs at
heart which can collect, process and transfer
data at a fast rate from multiple peripherals.
No matter at how much high frequency the
single core is operating on, it will always have
performance bottlenecks & challenges while
performing multiple tasks. Single core running
on higher frequency consumes more power.
This makes the single core architecture unfit
for ultra low power applications. Dual core
based SOC architecture provide better tradeoff
Fig 3 Heterogeneous Dual Core MCU
in performance and power consumption than
Dual core MCU can offer an integrated single
single core based architectures. As a result, the
chip solution for such applications, where one
dual core SoCs have now been featuring
core handles the communication and other core
prominently
designs.
handles the control tasks. However, using the
Besides providing higher performance than
same core for control and communication,
single core, dual core based architectures are
leads to compromise on performance of one or
in
the
automotive
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International Journal of Engineering Trends and Technology- Volume4Issue3- 2013
the other because control and communication
ADVANTAGES:
have different processor requirements. The
1. More reliable due to Heterogeneous Dual
control peripherals such as pulse width
Core MCU
modulators, time capture modules etc are
2. Less power consumption due to solar panel
mapped to the C28x. The communication
3. More users friendly
peripherals such as Ethernet and USB are
4. Low complexity and low area occupancy
mapped to the M3 core. A single analog to
APPLICATIONS:
digital converter is shared by both the
1.
Power stations
processors. Having ADC access by both cores
2.
Mobile communications
with
of
3.
Military communications
redundancy in the system, for safety critical
4.
satellite communications
different
checks.
ISA’s
This
split
adds
of
features
control
and
CONCLUSION:
Finally,
a
novel
communication tasks and peripherals between
instrumentation for the Hardware platform of
the two cores Provides a clean system
PV inverter is designed and implemented. This
partitioning. Communication between the two
project implements PV inverter topology with
processors is handled using an Inter Processor
isolation at high frequency. This project
Communication (IPC) peripheral which can
discusses the design of a smart
configure and has privileges to write. GUI
renewable energy node using a heterogeneous
shows the software structure used to pass
dual core microcontroller. In this case both the
messages and commands between the two
boost and the inverter stages are included.
CPU’s through the shared RAM’s. The IPC
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pp.1077-1080, 11-12 May 2010
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Sons,2011
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International Journal of Engineering Trends and Technology- Volume4Issue3- 2013
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