This document presents a bi-directional converter design for integrating renewable energy sources with the power grid. It describes a converter with 4 main modes of operation: boost mode, boost-buck mode, boost-boost mode, and battery boost mode. It then proposes a modified design that adds a 5th reverse buck mode, which allows the battery to be charged from the grid. The bi-directional converter aims to maximize efficient utilization of renewable energy and provide uninterrupted power by allowing energy transfer between the renewable source, battery storage, and grid. It reduces power electronics components compared to conventional designs. The document concludes there is potential to further optimize charging of the battery from both renewable and grid sources.

1. Guided By
Prof S.K. Sanyal
Presented By
Soumya Prateek Muni
M.Tech 2nd Semester
Power Electronics &
Drives
Bi-Directional Converter For
Renewable Energy Sources
INSTITUTE OF TECHNICAL EDUCATION AND RESEARCH

2. Contents
 Introduction
 Use of Renewable Energy
 Bi-directional Converter Concept
 Modes of Operation
 Modification For Better Performance
 Advantages
 Future Scope
 Conclusion
 References

3. Introduction
 Global energy consumption is increasing dramatically
due to our need for higher living standards and an
increasing world population. Most of our energy
comes from fossil fuels, and burning these fuels
causes global warming. Global warming raises the
sea level, brings drought to tropical regions near the
equator, increases hurricanes, tornadoes and floods,
and spreads disease.
 The quest for cleaner and more reliable energy
sources has considerable implications to the existing
power transmission and distribution system as well.
Traditionally bulk of the power is generated and
distributed to the large load centers via transmission
lines. The transfer of power was always one way,

4. Objective
 The alarming use of power make us to think for
alternate energy resources. But generating
capacity of renewable sources is limited as per
the availability of resources and technological
advancement. So to reduce the burden and to get
uninterrupted power we can integrate with grid.
Here our objective is to design a converter which
can provide power to grid as well as to a storage
device so in case of exigency it feed power to
grid. So uninterrupted and efficient utilization of
renewable source is achieved.

5. Use Of Renewable Energy
 Wide-spread demand and use of alternative and
renewable energy sources in distribution
networks are expected in the near future to
overcome the global shortage of fossil based
energy sources.
 The main advantages of renewable energy
generation are the elimination of harmful
emissions and inexhaustible resources.
 However, higher generation cost, uncontrollability,
and reliability issues are the disadvantages of the
renewable energy sources.
 Therefore a hybridized generation system is
typically used employing energy storage systems.

6. Converter Concept
Basic Components of a renewable source consist
of
 Boost Converter: Step up the voltage
 Buck-Boost Converter (Bidirectional type and
storage is connected which can transfer energy in
either way)
 Inverter: Converting DC voltage to Ac

7. Bidirectional Converter Model
 Conventional circuit: boost + bidirectional
converter
 Proposed Circuit : same functionalities with
bidirectional converter only
 4 modes of operation

8. Mode-I(Boost Mode)
 To boost the output voltage
 Both switches on : L1 charged from source
 During Toff: Vin+Vind transferred to load
 Output Voltage is like the output of boost
converter Current
Direction

9. Mode-II(Boost-Buck Mode)
 Duty ratio of SWa is greater than SWb
 SWa & SWb on: voltage is boosted
 SWa on & SWb off: load is supplied as well as
battery is charged
Both
Switch
On
One
Switch
only
Both
Switch
OFF

10. Mode-III(Boost-Boost Mode)
 SWb is greater than SWa
 Battery discharge energy to inverter when
shortage of generation from renewable source
Both on

11. Mode-IV(Battery Boost Mode)
 Very low or No generation from input side
 No role of SWa
 Only SWb control is required to feed all the
required power from battery to inverter

12. Modified Model
 Vital disadvantage: battery can’t be charged from
grid
 Power supply interrupted due to fault or low
generation
 Diode replaced by a Diode & Switch configuration
 Diode is acting for all the previous modes and
switch for an extra mode called Reverse Buck
Mode

13. Mode-V(Reverse Buck Mode)
 Uses SWc & bi-directionality of the inverter
 Dc obtained either by giving no pulse or by
controlling the pulses of Universal Bridge inverter
 When SWa is ON ,SWc ON batterty is charged
 SWb is always OFF, no control needed
Both ON
Only
SWc

14. Advantages
 maximize the cost efficiency reducing number of
switching elements
 Flexible interaction of battery with grid and
renewable energy resources
 Uninterrupted power supply
 Less power electronics circuitry as compared to
conventional

15. Conclusion
 Renewable sources are the future of the power
system. Integrating with the conventional grid
solves the power shortage issue up to a
maximum instant. Bidirectional Converter are of
great use in order to convert dc power to ac. The
storage with proper switching is integrated in the
circuit. Flexible charging of battery could be
implemented in order to implement the circuit in
more broad way.

16. Future Scope
 The model described here reduces the burden of
extra power electronics circuit. Here the battery is
charged either from the renewable sources or
from the grid. For more advanced application this
may be considered a base for designing a circuit
which along with the benefits described here also
charge the battery simultaneously. In order to get
optimum feasibility of this model there is wide
scope of the charging the battery simultaneously
by using advanced power electronics converters.

17. Reference
 Taesik Park; Taehyung Kim; , "Novel multi-mode
single leg converter for renewable energy
conversion systems," Industrial Technology
(ICIT), 2011 IEEE International Conference on ,
vol., no., pp.198-203,14-16 March 2011
 F. Blaabjerg, and Z. Chen, “Power electronics as
an enabling technology for renewable energy
integration”, Journal of Power Electronics, vol. 3,
no.2, 2003, pp. 81-89.
 Available: www.smartgridresearch.org
 Kwang-Hwa Liu, F.C. Lee, “Topological
constraints on basic PWM converters”, PESC
1988, pp164-172

18. THANK YOU