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1. A HYBRID AC/DC SOLAR POWERED STANDALONE SYSTEM
WITHOUT INVERTER BASED ON LOAD CHARACTERISTICS OF HOME
APPLIANCES
1
Mrs. Sumangala S Jambli, 2
Mr. Ramesh V Dixit, 3
Dr. Eswaramoorthy M
1- Assistasnt professor, ACS College of engineering, Department of EEE, Bangalore-560074, India
2-Student, M.Tech 3rd
sem, UVCE, Bangalore-560001, India
3-Professor &Head, Department of mechanical Engineering, ACS college of engineering, Bangalore560074,
India
1
sansumj@gmail.com, 2
ramvdixit13@gmail.com, 3
rmeswar@yahoo.com
1. INTRODUCTION;
The global demand for energy is currently growing beyond the limits of installable generation
capacity. To meet future energy demands efficiently, energy security and reliability must be
improved and alternative energy sources must be investigated aggressively.
Therefore, RES (renewable energy source) became one of the important topic for research in
the recent years. As a result, REC such as solar photo voltaic cell. Wind etc., are integrated in
a power system. The integration of RES at a distribution level is termed as a distribution
generation. Solar energy devices can benefit the environment and economy of developing
countries. Apart from large solar PV installations in China, Japan, India and US, Asian and
African countries have also shown a sharp inclination towards solar PV due to its simplicity in
comparison to other renewable energy systems as well as its low cost.
High penetration of RES causes issues in stability, voltage regulation and power quality of the
system. This becomes a threat to a network. The quality of power exchanged, at the point of
coupling is termed as power quality. It also depends on quality of voltage and current. We can
convert sun light into electricity in many ways like it can be converted by using solar cells or
with concentrated solar power (CSP), in which we throw the amplified sunlight to boil the
water which can then be used to produce electricity. During generation and conversion stages
due to some of the power quality issues like over voltage, harmonics & flickering will create
distortions due to which efficiency will get reduced. The first sign of a power-quality problem
is a distortion in the voltage waveform of the power source from a sine wave, or in the
amplitude from an established reference level, or a complete interruption. The disturbance can
be caused by harmonics in the current or by events in the main voltage supply system. The
disturbance can go for a fraction of a cycle (milliseconds) to great durations (seconds to hours)
in the voltage supplied by the source.
In order to overcome the above issues, the distribution and generation systems are required to
act with technical and in a regularity frame work, to protect and secure the network in order to
achieve reliable and cost effective operation of the network. Hence, the distribution and
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2. generation can actively controlled to enhance the system operation with improved power
quality.
Here 2 different effective methods of solar energy utilization are compared evaluated
experimentally and simulated using MATLAB/PSpice w.r.t load characteristics of residential
loads.
2. LITERATURE SURVEY:
Since modern household loads have different and more complex characteristics compared to
the loads used a decade ago, a detailed study of the actual behavior of modern loads is very
important in the distribution sector for power flow and harmonic analysis. The current
resurgence of interest in the uses of renewable energy is driven by the need to reduce the
negative impact of fossil fuel based energy system. Harvesting renewable energy on a large
scale is undoubtedly, one of the main challenges of our times. Future energy sustainability
depends heavily on how the renewable energy problem is addressed, in the next few decades.
Nikhil Sasidharan et. al [1] introduced experimentally verified ZIP coefficient model for most
commonly used appliances, which will help in the proper sizing of electric loads in buildings.
This method eliminates redundant power conversion stag by a shift of harmonic intensive
loads to the Direct Current (DC) network side. It mitigates some of the harmonics related
problems and efficiency issues by proposing a hybrid AC/DC Home grid system.
Sreya G. Grace Mathew et. al,[2] describes the issues caused by high penetration of RES for
stability, voltage regulation and power quality of the system. The same has been described
above in the previous sections. They have also suggested the generation of a gate pulse by
hysteresis control method for a grid interfacing inverter which is connected to a three phase
four wire system.
Po-Cheng Chen et. al [3] : five different P&O MPPT algorithms have been compared on both
transient and steady-state performance.
Brian T. Patterson[4] discusses the importance of micro grids.
Eduardo F. Comacho et, al.[5], are of the opinion that, the main source of energy, which is
fuel, can be manipulated in most of the power generating system, which is not true in case of
solar and wind energy. The main problem with these energy sources are cost and availability.
Wind and solar power are not always available where and when needed.
Shah Arifur Rahmanet.al., [6], presents a generalized mathematical model of a PV panel
utilizing only the quantities provided in manufacturer's datasheet. The proposed modelling
technique determines all the PV panel parameters without any explicit repetitive iteration.
Vijay Devabhaktuniet. al.,[7], introduced a new mechanical setup which can generate the
sine wave of any frequency by just controlling the speed of motor.
ISBN-13: 978-1539669203
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3. Jaume Salom et al. [8] notes the importance and role of net zero energy buildings in the future
power system. Since loads working on AC power still constitute a good part of present day
loads, converting the entire system to DC will not be possible due to the unavailability of DC
equipment for all applications.
Though there is an increase of electric devices that can generate or operate on DC power [9], a
solar PV systems first generates DC power, then into AC power for injecting into the household
wiring system and then
converts it back to the DC form as required by the loads.
Bokhari et al. [11] proposed a new method for experimentally determining the ZIP load model
of equipment in the US system at 110 V, 60 Hz and tested to determine individual equipment
coefficients. In order to study the complex behavior of loads, static ZIP load modelling is used
to model individual household loads. Therefore, there is a need to develop simulation models
for modern home appliances of a 220 Volts, 50 Hzsystem, mainly used in Europe and Asia, to
determine their effect on power quality, such as in terms of harmonics, the K-factor and
distortion power.
Shira Horowitz et.al[12], introduced a doubly censored Tobit model is used to forecast hourly
air-conditioner usage for individual households.
Molitor et al. [15] proposed an algorithm that can generate the load profile of a household
system for simulation studies using annual energy consumption. The standard load profile
given by a utility company to model the load profile was used.
Load modelling of remote villages is done using the energy consumption data for domestic
electrical appliances by considering the time of usage, the frequency of operation etc. [16].
3. OBJECTIVES:
To design a grid interfacing inverter which compensates power quality problems and also
interface RES to the power grid.
To obtain a more significant data for planning and operation of the home-grid.
To find a solution to mitigate some of the harmonics related problems and efficiency issues by
proposing a hybrid AC/DC Home grid system
To find an efficient method to apply to any building that has installed renewable DC sources,
like solar PV, a fuel cell, etc
To find compatibility of domestic loads by generating AC supply directly from solar cells by
avoiding the stages of inverter and battery.
To evaluate the performance of a hybrid AC/DC solar powered home-grid system & smart
solar AC generator without inerter and battery based on load characteristics of home
appliances.
ISBN-13: 978-1539669203
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Proceedings of ICRTE-2016
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4. 4. METHODOLOGY:
The performance of a new hybrid AC/DC solar powered Home-grid model is evaluated based
on the load characteristics of a typical set of home appliances working on a 220V, 50Hz system
with another solar AC generator without inverter. The methodology has mainly 2 performance
analysis of two methods of solar energy generation.
Method 1
In the first part load characteristics of home appliances are represented by a suitable load model
which will be useful in load modeling in power flow studies.an experimental determination of
a load model of commonly used modern home appliances for a 220V, 50Hz supply system by
varying the voltage condition is analyzed, which will be very beneficial for power system
planning and power flow studies. By analyzing the harmonics contribution of each household
load, a new hybrid AC/DC solar powered Home-grid system is proposed for residential
buildings, aiming to reduce the harmonics and, thus, improve the efficiency of the system
having both AC supply (220 V, 50 Hz) and DC supply. The power is taken from the solar panel
with power cables with the ―connection from solar panel. This box is connected to a DC-DC
converter with a circuit breaker to the extract maximum power from the solar panel. This is
called maximum power point tracking (MPPT). Then, this DC-DC converter is connected to a
DC-AC inverter to supply the household appliances which will work in 220 V, 50 Hz. A
separate DC connection is taken from the DC-DC converter to connect DC loads . The loads,
which are harmonic intensive as well as easy to transfer, are proposed to be shifted to the DC
side of the network system to reduce unnecessary power conversion losses and also to isolate
the harmonic contents from the grid system. Apart from being energy efficient, this hybrid
Home-grid system is also equipped to inject the excess generated solar PV power into the grid
in order to achieving a net zero or surplus energy building status as well. The conventional AC
loads are supplied using a single phase inverter. For controlling this single phase inverter, a PQ
controller is used, considering the advantage that it will control the active and reactive power
according to the reference signal. Since the controlling elements for the AC system are very
difficult due to their time varying nature, the AC control variables are converted to a stationary
reference frame from a rotating reference frame for effective control.
ISBN-13: 978-1539669203
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Proceedings of ICRTE-2016
©IIRDEM 201657

5. Fig.1 Control block diagram of the hybrid AC/DC solar powered Home grid
In second arrangement the placing of solar cells will be in circular form so that the pair of anti-
parallel connected photovoltaic cells of each photovoltaic cell pair progressively and
alternately get exposed and shaded causing the amplitude and polarity of the waveform at the
AC output to slowly and steadily rise and fall to make alternating current. To arrange solar
cells in a circular array perfectly AutoCAD can be used.
Fig.2 Array of solar cells connected in anti-parallel
A pair of solar cells A and B is shown in the figure. To generate an AC output wave the solar
cell pair is connected in anti-parallel. The negative terminal of the photovoltaic cell A is
connected with positive terminal of the photovoltaic cell B, whereas the negative terminal of
the solar cell B is connected to the positive terminal of the photovoltaic cell A. The AC output
terminals area out and Bout. The generated AC voltage compatibility is checked with
residential loads. This is a new technique for the generation of AC power from Solar panel
Home with
solar roof top
MPPT
Sepic
converter
DC/DC
converter
PWM
Inverter
DC-AC
SPWM PLL
1 PHASE
HOME
Appliances Gri
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PQ controller
P & Q ReferencesDC loads
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Aout
Bout
ISBN-13: 978-1539669203
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Proceedings of ICRTE-2016
©IIRDEM 201658

6. devoid of inverter. By adopting this technique we can remove power losses due to an inverter.
There is no need of batteries in our technique so overall cost is also reduced.
5. PROPOSED OUTCOME:
 This work introduces a novel solution to mitigate some of the harmonics related problems
and efficiency issues by proposing a hybrid AC/DC Home grid system.
 The electricity consumption pattern of different appliances, the share of appliances out of
total electricity consumption will be studied and presented by using load model. In the
absence of proper load models, power system analysis may produce erroneous results. This
work discusses the methods to model common residential electrical equipment, which will
be beneficial for further simulation study of distribution system stability.
 The response of the proposed phase locked loop will be validated and the effect of proposed
synchronization and the performance of grid connected RES will be investigated.
 As future work, the same procedures described here can be applied to distribution feeders.
The method can thus be used for more accurate predictions of the combined load behavior
and can give more significant data for the planning and operation of a Home grid.
 Behavior of the system with and without connection of the inverter will be studied.
 Practical analysis of power quality issues like, stability, harmonics and voltage regulation
with supporting results from MATLAB/SIMULINK simulation and experiments validates
the proposed approach.
REFERENCES:
[1]. Nikhil Sasidharan Nimal Madhu M Jai Govind SinghWeerakorn Ongsakul, “An
Approach for an Efficient Hybrid AC/DC SolarPowered Homegrid System
based on the Load Characteristicsof Home Appliances,” Energy and Buildings
(2015), http://dx.doi.org/10.1016/j.enbuild.2015.08.051 Accepted manuscript.
[2]. Sreya Grace Mathew, Fossy Mary Chacko , “power quality improvement in a grid
connectedrenewable energy system,” International Journal of Electrical,
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[3]. Po-Cheng Chen, Po-Yen Chen, Yi-Hua Liu, Jing-Hsiao Chen , Yi-Feng Luo, “A
comparative study on maximum power point tracking techniques for
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Solar Energy 119 (2015) 261–276
[4]. Brian T. Patterson[4] , DC Microgridsand the Birth ofthe “Enernet”, IEEE Power
& Energy Magazine, november/december 2012
ISBN-13: 978-1539669203
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Proceedings of ICRTE-2016
©IIRDEM 201659

7. [5]. Edurado F. Comacho, tariq samad, maria Garcia-sanz and ian hiskens“control for
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©IIRDEM 201660

8. [18]. Mukhtiar Singh, Vinod Khadkikar ,Ambrish Chandra andRajiv K. Varma,“Grid
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136, 31 December 2014.
ISBN-13: 978-1539669203
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Proceedings of ICRTE-2016
©IIRDEM 201661