Hybrid AC/DC Microgrid operation under critical load condition.

1. 
DISTRIBUTED CONTROL OF HYBRID AC-DC MICROGRID WITH SOLAR
ENERGY,ENERGY STORAGE AND CRITICAL LOAD..
PRESENTED BY:
K .BALA SRIRAM (13K81A0222)
S .SAI SRIRAMYA (13K81A0247)
S .VIJAY KUMAR (13K81A0241)
T .NAVEEN (14K85A0204)
PROJECT GUIDE :
BABITHA NANDA(PH.D)
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2. ABSTRACT
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This paper proposes a hybrid AC/DC Microgrid to reduce the processes of
multiple conversions (dc–ac–dc or ac–dc–ac) in an individual ac or dc source. The
hybrid grid consists of both AC bus and DC bus connected together by
bidirectional AC/DC converter. This Microgrid works in islanding mode. A
synchronous generator (AC source) and AC loads are connected to the AC bus.
The PV farm (DC source) is connected to the DC bus through a DC-DC boost
converter with maximum power point tracking (MPPT) functionality. DC load is
connected to the DC bus by means of a Battery bank through a bidirectional DC-
DC converter. A small hybrid grid has been modeled and simulated using the
Simulink in the MATLAB. The simulation results show that the system can
maintain stable operation under the proposed coordination control schemes when
the grid is switched from one operating condition to another.

3. AIM OF THE PROJECT
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 The aim of this project is to manage the power between the two
grids when it is operating in islanding mode under critical load
condition.

4. INTRODUCTION
 Microgrid concept widely for the better interconnection of DGs. Hybrid
AC/DC micro grids have been planned for the improved interconnection of
different distributed generation systems (DG) to the power grid, and
exploiting the prominent features of both ac and dc micro grids. In this
project consist of renewable energy utilization for the power management to
the grid. The source from the solar is fed to the DC bus bar then the amount
of required energy is given to the grid the balance energy is stored by the
battery storage by the means of DC-DC bidirectional converter. The load is
supplied from DC microgrid when the load demand increases the excess
power required will be delivered from AC grid through AC-DC bidirectional
converter[1].
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5. MODELLING OF PV ARRAY
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Equivalent circuit of PV panel

6. EEE DEPARTMENT
Below equations shows the mathematical model of the PV panel and
its output current[2]-[3].

7. MATLAB SIMULINK MODEL OF A PV
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8. PARAMETERS FOR PV PANEL
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9. BOOST CONVERTER CONTROL WITH MPPT
 BOOST CONVERTER
Boost converter steps up the input voltage magnitude to a required
output voltage magnitude without the use of a transformer. The main
components of a boost converter are an inductor, a diode and a high
frequency switch. These in a coordinated manner supply power to
the load at a voltage greater than the input voltage magnitude. The
control strategy lies in the manipulation of the duty cycle of the
switch which causes the voltage change[3].
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10. BOOST CONVERETR MATLAB SIMULINK MODEL
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11.  MAXIMUM POWER POINT TRACKING
The efficiency of a solar cell is very low. In order to increase the efficiency, methods are to be
undertaken to match the source and load properly. One such method is the Maximum Power Point
Tracking (MPPT)[4][5].
 METHODS FOR MPPT
There are many methods used for maximum power point tracking a few are listed below:
1. Perturb and Observe method
2. Incremental Conductance method
3. Parasitic Capacitance method
4. Constant Voltage method
5. Constant Current method

12. .
perturbation and observe algorithm
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13. BI-DIRECTIONAL DC-DC CONVERTER CONTROL
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The bi-directional converter of the batteries
play an important role in islanding mode to
regulate the DC bus voltage in both
directions that is charging and discharging
mode[6].

14. BI-DIRECTIONAL AC-DC CONVERTER CONTROL
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The frequency and voltage amplitude of the
three phase AC side is not fixed during
islanding operation so a device is needed to
regulate these variables. A bi-directional AC-
DC inverter is used with the active and
reactive power to keep the AC side stable[7].

15. ENERGY STORAGE UNIT
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An accurate battery cell model is needed to
regulate the DC bus voltage in islanding
mode. The battery terminal voltage and SOC
need to be estimated during operation. A high
fidelity electrical model of lithium-ion
battery model with thermal dependence is
used[8].

16. HYBRID MICROGRID SYSTEMPARAMETERS
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17. OVERALL VIEW
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18. REFERENCES
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1. S.Rohini, T.Sasikumar “POWER CONTROL AND MANAGEMENT IN A
HYBRID AC/DC MICROGRID USING DECENTRALIZATION
CONTROL SYSTEM” International Journal of Innovative Research in
Technology, Science & Engineering (IJIRTSE) ISSN: 2395-5619, Volume –
2, Issue – 1. January 2016
2. Moein Jazayeri, Sener Uysal, Kian Jazayeri “A SIMPLE
MATLAB/SIMULINK SIMULATION FOR PV MODULES BASED ON
ONE-DIODE MODEL” Published on IEEE 2013
3. Saurav Satpathy “PHOTOVOLTAIC POWER CONTROL USING MPPT
AND BOOST CONVERTER” A Thesis submitted in partial fulfillment of the
requirements for the degree of Bachelor of Technology in Department of
Electrical Engineering National Institute of Technology, Rourkela May 2012

19. 4. R. Sridhar, Dr. Jeevananathan, N. Thamizh Selvan, Saikat Banerjee,
“Modeling of PV Array and Performance Enhancement by MPPT
Algorithm", International Journal of Computer Applications (0975 – 8887)
Volume 7– No.5, September 2010.
5. Hairul Nissah Zainudin, Saad Mekhilef, “Comparison Study of Maximum
Power Point Tracker Techniques for PV Systems”, Cairo University, Egypt,
December 19-21, 2010, Paper ID 278.
6. Husam Ahmed Ramadan Ahmed “Modeling and Control of Bidirectional DC-
DC Converters for DC Power Systems with Renewable Energy”A Thesis
submitted in partial fulfillment of the requirements for the degree of Bachelor
of Technology in Department of Electrical Engineering Kyushu University
JAPAN December, 2014
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20. 7. Md. Parvez Akter, Saad Mekhilef “MODEL PREDICTIVE CONTROL OF BI-
DIRECTIONAL AC-DC CONVERTER FOR ENERGY STORAGE SYSTEM”
by Korean institute of Electrical Engineers Published in JEET.2015
8. T. Huria, M. Ceraolo, J. Gazzarri, R. Jackey, "High fidelity electrical model
with thermal dependence for characterization and simulation of high power
lithium battery cells," Electric Vehicle Conference (IEVC), 2012 IEEE
International pp.I,8, 4-8 March 2012
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21. Thank you