This paper presents a simulation of a DC/DC buck-boost converter for integrating a solar PV generation system into a DC nano-grid. The simulation models an MPPT algorithm to extract maximum power from the solar PV module and regulate the output voltage of the buck-boost converter at 12V and 24V using PI control. The proposed system directly feeds the maximum available DC power from the solar PV module to the DC nano-grid loads, improving efficiency by reducing conversion stages. The simulation results demonstrate the buck-boost converter maintaining a constant voltage on the DC bus regardless of variations in solar PV generation.

1. Simulation of DC/DC Converter for DC Nano-Grid Integrated with
Solar PV Generation
Rajesh M Pindoriya
Co-Authors,
S Rajendran
Indian Institute of Technology
Gandhinagar (IITGn)
Dr. N M Pindoriya
Indian Institute of Technology
Gandhinagar (IITGn)

2. Aim of a paper
Introduction of Nano grid
The need of Nano grid
Environmental aspects
Schematic layout of DC Nano grid integrated with solar PV
generation
Simulink Model of DC Nano grid
Future directions on Nano grid research
Conclusion
References
Outline

3.  Distributed energy resources (DER) based micro grid and Nano-grid framework is most technically
viable bottom-top approach to sustainably meet ever-increasing demand of rural and urban
communities.
 This paper presents simulation results of a buck boost converter, MPPT algorithm (P & O method)
for solar PV module and closed loop PI control system for obtaining constant 12 V and 24 V DC
output voltage at DC bus.
 The proposed methodology is to extract maximum DC power from solar PV system and it is directly
fed to DC load or DC Nano grid.
Aim of a paper

4. What is Nano grid?
It is a small-scale power supply network that is designed to provide power for a small community.
It comprises of various small power generating sources that makes it highly flexible and efficient.
It is connected to both the local generating units and the utility grid thus preventing power outages.
Excess power can be sold to the utility grid.
Size of the Micro grid may range from housing estate to municipal regions.
Nowadays, energy generate in form of clean, efficient, and environmentally friendly sources has
become one of the major challenges for engineers and scientists [1].
Introduction of Nano grid

5. Applications of DC Voltage
Fig.1. Hair dryers Fig.2. Ovens Fig.3. Laptop chargers Fig.4. Mobile chargers
 Recently the growth of DC operative home appliances like mobile and lap top chargers, ovens and
hair dryer’s are increasing
 Therefore a DC/DC converter is an efficient way to meet the electricity need from the local DER and
helps in improving the system efficiency

6. Micro grid could be the answer to our energy crisis.
Transmission losses gets highly reduced.
Micro grid results in substantial savings and cuts emissions without
major changes to lifestyles.
Provide high quality and reliable energy supply to critical loads
CO2 Emissions are reduced.
The Need of Micro grid

7. The efficiency of solar cells depends on many factors such as
1. Temperature
2. Insolation
3. Spectral characteristics of sunlight
4. Dirt
5. Shadow and so on.
 In addressing the poor efficiency of PV system some methods are proposed for improving an
efficiency of solar PV system among by implementing a new concept called “maximum power
point tracking” (MPPT).
 The DC/DC converter is responsible for transferring maximum power from the solar PV
module to the load. A MPPT is used for extracting the maximum power from the solar PV
module and transferring that power to the load [4].
Environmental aspects

8. Poly crystalline solar PV module
Vmpp =35.9 V, Impp= 8.22 A
Mono crystalline solar PV module
Vmpp =35.7 V, Impp= 7.99 A
Thin film solar PV module
Vmpp =79.0 V, Impp= 1.9 A
MPPT
(using P & O
algorithm)
MPPT
(Using P & O
algorithm)
MPPT
(using P & O
algorithm)
DC/DC
buck boost
converter
DC/DC
buck boost
converter
DC/DC
buck boost
converter
DC/DC
buck converter
Charging
station for
mobiles
Charging
station for
mobiles
Battery
energy
storage
(BES)
Battery
energy
storage
(BES)
24 V DC bus bar
12 V DC
24 V DC
Vmpp =71.8 V
Vmpp =71.4 V
Impp =3.8 A
Schematic layout of DC Nano grid integrated with solar PV generation

9. Solar PV
module
DC load
VI
MPPT algorithm and duty cycle
modification (PI controller)
DC/DC converters
(Buck, Boost,
Buck- Boost, Cuk)
Converter)
Pictorial view of DC Nano grid with MPPT and PI controller
 Power delivered by a module depends on the load
connected to the module.
 MPPT is algorithm that included in charge
controllers used for extracting maximum available
power from PV module under certain conditions.
 The voltage at which PV module can produce
maximum power is called ‘maximum power point’
or peak power voltage.
 MPPT is most effective under, cold weather, cloudy
or hazy days.
 There are large number of algorithms that are able
to track MPPs.

10. Simulation of DC Nano grid integrated with monocrystalline solar PV module

11. Simulink Model of DC DC converter
Fig. 5. Simulink diagram of closed loop buck boost
converter with PI controller
 Recently, the deployment of DC appliances is
exponentially increasing in all sectors like,
industrial, commercial and domestic
customers.
 In addition, the solar PV module generates DC
power and therefore it can be directly fed to
DC load through DC/DC converter to
minimize the conversion losses and improve
power quality and efficiency.
 Output voltage of buck boost converter is
define as below.
𝑽 𝒐𝒖𝒕 = −
𝑽𝒊𝒏 ∗ 𝑲
𝟏 − 𝑲

12. Fig. 6. I-V Characteristic of mono crystalline 285 W
solar PV module
Fig. 7. P-V Characteristic of mono crystalline 285 W
solar PV module
Characteristics of Mono Crystalline Solar PV module

13. Fig. 8. DC 12 V output voltage of buck boost converter Fig. 9. DC 24 V output voltage of buck boost converter
Output Voltage of Buck Boost Converter
This small level DC output voltage is directly fed to DC equipment’s like, (laptop battery, mobile charger
and battery charging).

14. Sr. No. Advantages Disadvantages
1 Significant environmental benefits made possible by
the use of low or zero emission generators.
Electrical energy needs to be
stored in battery banks thus
requiring more space and
maintenance.
2 The use of both electricity and heat permitted by the
close proximity of the generator to the user, thereby
increasing the overall energy efficiency.
Resynchronization with the
utility grid is difficult.
3 Nano grid protection is one of the
most important challenges facing
the implementation of Nano
grids.
Advantages & Disadvantages of Nano grid

15.  To investigate full-scale
development, field demonstration,
experimental performance
evaluation of frequency and
voltage control methods under
various operation modes.
 Transition between grid connected
and islanded modes on interaction
phenomena between distribution
generation and high penetration of
distributed generation.
 Transformation of Microgrid
system today into the intelligent,
robust energy delivery system in
the future by providing significant
reliability and security benefits.
5/27/2016
Future Directions on Nano grid Research

16. Conclusion
 This paper simulates the DC-DC converter for application of DC Nano grid, at two voltage levels: 12 V &
24 V DC output voltages from buck boost converter.
 This small level DC output voltage is used for small home appliances load.
 The constant DC output voltage is obtained through two level using PI controller and MPPT algorithm
for track maximum power from solar PV module.
 The simulation results demonstrate the buck-book converter application for maintain constant voltage at
DC bus irrespective of variation of solar PV generation.
 Also it improves the system efficiency by reducing no. of conversions.

17. References
1. A. Safari and S. Mekhilef, “Simulation and Hardware Implementation of Incremental Conductance MPPT
With Direct Control Method Using Cuk Converter”, IEEE Trans. Ind. Electron, vol. 58, no. 4, pp. 1154 – 1161,
Apr. 2011.
2. W. Xiao, W. G. Dunford, P. R. Palmer, and A. Capel, “Regulation of photovoltaic voltage,” IEEE Trans. Ind.
Electron., vol. 54, no. 3, pp. 1365– 1374, Jun. 2007.
3. K. K. Kalyan, R Bhaskar, and H. Koti, “Implementation of MPPT algorithm for solar photovoltaic cell by
comparing short circuit method and incremental conductance method,” Science Direct, The 7th Inter. Conf.
Interdisciplinary in Engineering (INTER-ENG 2013), Procedia Technology 12, pp. 705-715, 2013.
4. K. Y. Chen, T. J. Liang, J. F. Chen, “Novel maximum power-point tracking controller for photovoltaic energy
conversion system” IEEE Trans. on Ind. Electro., vol. 48, no. 3, pp.594-601, Jun. 2001.
5. S. Kjaer, J. Pedersen, and F. Blaabjerg, “A review of single-phase grid connected inverters for photovoltaic
modules,” IEEE Trans. on Ind. App., vol. 41, no. 5, pp. 1292–1306, 2005.
6. E. Koutroulis, K. Kalaitzakis, and N. C. Voulgaris, “Development of a microcontroller-based, photovoltaic
maximum power point tracking control system,” IEEE Trans. Power Electron., vol. 16, no. 1, pp. 46–54, Jan.
2001.
7. E. Koutroulis, K. Kalaitzakis, and N. C. Voulgaris, “Development of a microcontroller-based, photovoltaic
maximum power point tracking control system,” IEEE Trans. Power Electron., vol. 16, no. 1, pp. 46–54, Jan.
2001.

18. THANKS