pwm bidirectional converter

1. SINGLE PHASE BIDRECTIONAL PWM
CONVERTER
FOR MICROGRID SYSTEM
GUIDED BY
Ms.SREELAKSHMI.C.S
GROUP MEMBERS
MRUDHULA.M.K
NAIR.P.AKSHAY
ROOPESH.R.NAIR
VIVEK.K.P Monday, January
30, 2017
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2. OBJECTIVE:-
 Proposes a control system for single-phase bidirectional PWM converters for residential
power level Microgrid systems which is robust.
 Which can tolerate transitions between the different modes of operation.
 The Microgrid connected single phase Bidirectional PWM converter which operates in
Rectification and Inverting mode.
 This converter helps to connect renewable energy sources to loads as well as excess power are
given to power grid.
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3. INTRODUCTION:-
 The existing electricity grid converts only one-third of fuel into electricity and 8% of its
output is wasted across the transmission lines.
 Smart grid technology basically derived from traditional power grid with some additional
features such as reliability, efficiency and sustainability .
 The conventional methods of power generation are affect the environment, causing an
increase in greenhouse gas emissions.
 These methods of generations have exceptional scale of economy, But it transmits power over
long distances.
 As a result, it has turn into the driving force for the growing interest in alternative energy.
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4.  Distributed generation is one approach to the manufacture and transmission of electric power.
 In this generation the power is generated locally hence the transmission loss is reduced and size
and number of power line is also reduced.
 Microgrid is an accepted concept that consists of generating units and storage elements and
uses the naturally available alternate energy resources.
 The critical component for such a system is the ac/dc bidirectional, pulse width-modulation
(PWM) converter.
 That connects the ac and dc subsystems together and to the utility grid.
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INTRODUCTION CONTINUES..

5. MICROGRID BENIFITS
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Provides power quality, reliability, and
security for end users and operators of the grid.
Enhances the integration of distributed and
renewable energy sources.
Cost competitive and efficient.
Locally controlled power quality.
Minimize carbon footprint and green house gas
emissions by maximizing clean local energy
generation.

6. BLOCK DIAGRAM:-
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7.  The bidirectional converter should operate in the following modes:
 1) Inverter Mode
 2) Rectifier Mode
 Inverter Mode:-
If the dc side renewable energy is available converter operates as the
Inverter feeding power to the ac loads and dc loads directly get power from
renewable energy sources.
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8.  Rectifier Mode
 In this mode the converter act as a full bridge inverter and LC filter is used to get
the sinusoidal output.
 If the dc side renewable energy is not available converter operates as the rectifier
feeding power to dc loads .
 AC side renewable energy resources provide power to AC loads.
 In this mode the converter act as a rectifier and provide DC output with less ripple
factor by using filter capacitor Cdc.
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9. CONTROL SYSTEM DESIGN:-
 In recent years many control strategies have been developed for example hysteresis and
predictive control ,fuzzy logic, sliding mode ,repetitive control and neural network.
 In this methods each mode requires different control strategy which results difficulty in
control system design and over all reliability of the system is reduced.
 Therefore the Double loop PID control is proposed because of simple design, easy
implementation and excellent performance.
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10.  Before designing the control system, converter has to be modeled. The Average model of the
full bridge inverter is given by the following equation (1) & (2)
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11.  Since the double loop control is used, the current loop is used to regulate the inductor current
and the voltage loop is used to regulate ac and dc voltage.
 The current and voltage loop is designed separately. Transfer function for current and voltage
loop can be obtained from the average model given by the equation (1) & (2).
 Transfer function for common inner current loop,
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12.  Transfer function for outer voltage loop,
 Inverter Mode
 Rectifier Mode
 The desired output for a closed loop system is obtained by tuning PID gain values
to the system inherent condition.
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13. CIRCUIT DIAGRAM
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14. SIMULATION:-
 The control system is designed and simulated using MATLAB/simulink.
.
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PARAMETER RANGE
Input voltage 230V
Vrms 230V
AC filter inductor 220e-6H
AC filter capacitor 25e-6F
DC filter inductor 500e-3H
DC filter capacitor 7.5e-3F
Rdc 100Ω
Rac 20Ω
Lac 45.5e-3H
Cac 150e-6F
Switching frequency 25kHz
Voltage sensor gain 0.01(Inverter)
0.03(Rectifier)
Current sensor gain 0.06

15. CIRCUIT OPERATION
Inverter mode
 In this mode the switches(IGBT) S3 and S4 are turned ON
 Current follows the path starting from the DC source.
The path is
K Is L1 S3 F RLC Parallel C2 L2
b T4 L I J
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16. Monday, January
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INVERTER MODE
 SIMULATION DIAGRAM

17.  INVERTER OUTPUT
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18.  CURRENT LOOP
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19.  VOLTAGE LOOP
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20.  PWM SWITCHING
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21. Monday, January
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RECTIFIER MODE
 SIMULATION DIAGRAM

22. Monday, January
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22  VOLTAGE LOOP
 CURRENT LOOP
• Current loop is same as the inverter mode.

23. Monday, January
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23  RECTIFIER OUTPUT

24. APPLICATION:-
 It helps to connect both DC and AC loads to a Microgrid system.
 It helps to regulate ac and dc voltage.
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25.  The Literature survey for the project was done.
 Current and voltage loop PID are designed.
 The simulation diagram for the Bi-directional converter in inverter mode is drawn.
 Varying peak amplitude is obtained.
 The voltage loop for rectifier is designed.
 The rectifier output with noise is obtained.
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CONCLUSION:-

26.  Dong Dong, Timothy Thacker, Igor Cvetkovic, Rolando Burgos, Dushan Boroyevich,
FredWang, and Glenn Skutt “Modes of Operation and System-Level Control of Single-
Phase Bidirectional PWM Converter for Microgrid Systems”.
 D. Dong, T. Thacker, R. Burgos, D. Boroyevich, F. Wang, and B.Giewont, “Control design
and experimental of a multi-function single phase bidirectional PWM converter for
renewable energy systems,”.
 C.Kalavalli, K.ParkaviKathirvelu, R.Balasubramanian “Single Phase Bidirectional PWM
Converter for Microgrid System.” International Journal of Engineering and Technology
(IJET) Vol 5 No 3 Jun-Jul 2013
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REFERENCE:-

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