This document summarizes a project on bidirectional buck boost cascade inverters. It presents: 1. An abstract describing a bidirectional buck boost cascade inverter that uses a buck converter stage to maintain inductor current and a boost converter stage to control output voltage. 2. Descriptions of buck and boost converter operations, components, and applications such as battery charging. 3. Explanations of fuzzy logic controllers, including their advantages over PID controllers for uncertain or nonlinear systems. 4. A comparison of PID and fuzzy logic controllers, noting that fuzzy controllers can achieve high performance by eliminating system nonlinearities.

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Department of electrical and electronics engineering
Gandhiji institute of science and technology Approved by AICTE,NEW DELHI,
Affiliated to JNTU KAKINADA , Gattu Bhimavaram ( p. o)-
521178,VATSAVAI(M),
JAGGAYYAPET , Krishna District www.gistech.co.in

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PRESENTED BY:
SK.SHABEER(14JF5A0201)
HARIKESH CHAUHAN(13JF1A0209)
A.ASHOK(13JF1A0201)
SUMBUL SABA(13JF1A0228)
RAJESH KUMAR(13JF1A0225)
UNDER GUIDE BY:-
U. NARESH M.Tech
asst professor
.
HEAD OF THE DEPARTMENT:-
M.SUNDAR RAO M.Tech
Associative professor

3. Contents.......
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 Abstract.
 Different Types Of converters
 Buck Converter
 Boost Converter
 Buck- Boost Converter
 Different Types Of Controller( p, pi , pid And Fuzzy)
 Fuzzy Controller
 Advantages, Disadvantages And Application Of Our
Projects
 Conclusion
 Queries

4. Abstract ......
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 This paper proposes a bidirectional buck boost cascade inverter
and presents its modelling and control methods
 Here the inverter can be seen as the cascade of a buck converter
and boost converter main inductor current is maintained by
buck stage and out voltage controlled by boost stage
 It provides bidirectional operational with bipolar outputs.
It reduces the dead time effect and reduced output distortion

5. OPERATION OF BUCK STAGE
 Buck converter is a dc- dc power converter
 it is a class of switched mode power supply(SMPS)
 It containing two semiconductors (Diode & IGBT)
 To reduce voltage ripple , filters made of capacitor & inductor
 Buck converter provide much greater power efficiency
APPLICATIONS:-
It is used in many industrial application such as cars trolley buses
battery operated vehicles and battery charging etc....
To provide smooth control on output high efficiency , fast response and
regeneration.
To provide long and less maintenance due to absence of moving parts.
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6.  Operation of boost stage:-
Output voltage always higher than input voltage
Boost converter is dc-dc power converter
It is a class of switch mode power supply (SMPS)
When switch is “on” : diode is reverse biased output circuit is thus isolated
inductor is charged.
When switch is “off “: output stage received energy from the inductor as
well as input.
Filter capacitor is very large to ensure constant output voltage .
In this diode and transistor is used as switching device .
It is voltage control device and it required small amount of current
Switching speed is very high.
It operates in nano second.
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7. Circuit diagram:-
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8. What is a fuzzy controller
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 Fuzzy logic controller developed by Zadesh in 1965.
 Fuzzy logic control is rule based technique.
 The rules are “IF THEN” rules
 Fuzzy logic control can be well suited to control a system
with uncertain, complex , inaccurate or non linear
dynamics..
 In fuzzy logic controller we used membership functions

9. Why should we use fuzzy controller
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 Very robust
 It can be easily modified.
 Can used multiple inputs and outputs sources.
 Very quick and cheaper to implement.
 Much similar than its predecessors.

10. Types of controllers
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 P-controllers (proportional controllers)
 I-controller (integral controller)
 PI-controller(proportional+ integral controller )
 PD- controller(proportional +derivative controller )
 PID- controller (proportional + integral +derivative
controller )

11. PID-controller:-
11 A controller in which the output are control signal
is a sum of three signals one being proportional to
error signal one being proportional to integral of
the error signal and third being proportional to
derivative of error signal is known as PID
controller.
Advantages:-
o It improves the system performance in all aspects
due to combined operation of three.
o “P” of PID controller increase the gain of system.
o “I” of PID controllers decreases the steady state
error.
o “D” of PID controller decreases the rate of change
of error.

12. Compare PID and fuzzy logic controllers
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 Reduced output distortions.
 High performance achieved
 Which can be utilized to eliminate the systems non
linearity.
 Quick speed.

13. ADVANTAGES:-
 GREATER POWER EFFICIENCY
 SIMPLE CIRCUITS
 HEAT DISSIPATION IS LESS
 LESS SEMI CONDUCTOR DIVICES ARE REQUIRED
DISADVANTAGES:-
 IT DOES NOT STEP - UP THE OUTPUT CURRENT
 IT IS COSTLY AVAILABLE IN THE MARKET
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14. OUTLINE DIAGRAM
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15. CONCLUSION:-
Which can be utilized to eliminate the system nonlinearity , and thus high
performance acheived
Consequently , a decoupled control strategy with feed forward compensation
technique is proposed .
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