This document describes a study that designed a fuzzy logic controller for a boost DC-DC converter using MATLAB/Simulink software. The objective was to develop a fuzzy logic algorithm to control the output voltage of the boost converter in steady state conditions. Simulation results showed that the fuzzy logic controller was able to maintain the output voltage with no overshoot, unlike the open loop converter which had 80% overshoot. In conclusion, the fuzzy logic controller improved the dynamic performance and stability of the boost converter compared to an open loop design.

1. PRESENTED by -
RAGHVENDRA KUMAR PANDIT
B.TECH 3RD YEAR (6TH SEM)
BRANCH –EE
SECTION –A2
ENROLL NO. –MUR1301260
Submitted to-
MR.V SIVA brahmaiyah rama
Topic –Fuzzy Logic Controller on DC/DC Boost Converter
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2. ABSTRACT :-
This paper describes the design of a fuzzy logic controller using
voltage output as feedback for improving the dynamic
performance of boost dc-dc converter by using
MATLAB@Simulink software. The objective of this proposed
methodology is to develop fuzzy logic controller on control
boost dc-dc converter using MATLAB@Simulink software. The
fuzzy logic controller has been implemented to the system by
developing fuzzy logic control algorithm. The design and
calculation of the components especially for the inductor has
been done to the converter operates in continuous conduction
mode. The evaluation of the output has been carried out and
compared by software simulation using MATLAB software
between the open loop and closed loop circuit. The simulation
results are shown that voltage output is to be control in steady
state condition for boost dc-dc converter by using this
methodology.
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3. INTRODUCTION:-
Nowadays, the control systems for many
power electronic appliances have been
increasing widely. Crucial with these
demands, many researchers or designers
have been struggling to find the most
economic and reliable controller to meet
these demands. The idea to have a control
system in dc-dc converter is to ensure
desired voltage output can be produced
efficiently as compared to open loop system.
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4. WHAT IS FUZZY LOGIC:-
 The idea of fuzzy logic was first advanced by Dr. Lotfi
Zadeh of the University of California at Berkeley in the
1960s. Dr. Zadeh was working on the problem of computer
understanding of natural language. Natural language (like
most other activities in life and indeed the universe) is not
easily translated into the absolute terms of 0 and 1.
 Fuzzy logic is an approach to computing based on "degrees
of truth" rather than the usual "true or false" (1 or 0)
Boolean logic on which the modern computer is based.
Fuzzy logic seems closer to the way our brains
work.
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5. BOOST DC/DC CONVERTER:-
 Output voltage always higher
than the input voltage
 When the switch is ON:-
Diode is reversed biased
output circuit is thus isolated
inductor is charged.
 When the switch is OFF:
The output stage received
energy from the inductor as
well as from the input.
 Filter capacitor is very large
to ensure constant output
voltage
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-
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6. SWITCHING DEVICE:-
 In this MOSFET is used as
switching device
 It is voltage controlled
device and also it requires
small input current
 Switching speed is very
high
 It operates in nano sec’s
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7. Boost converter for MATLAB:-
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8. Block Parameters For Converter:-
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9. Block Parameters For Converter:-
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10. Block Parameters For Converter:-
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11. MATLAB Simulation Figure:-
Fig. Output voltage for Boost converter
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12. ADVANTAGES:-
 Only one switch
 High efficiency
 Unidirectional output current
 Provides one polarity output voltage
 Low cost
 Easy to analyze
 Easy to understand
 Simple circuit
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13. DISADVANTAGES:-
Not suitable for high power conversion
Low amount of dc step up
Non isolated SMPS
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14. APPLICATIONS:-
Commonly used as LED driver
Used for Solar power system
Used for Power factor corrections
Used in HVDC system
Applicable for LCD Back & FLASH LIGHTS
Used in HVE(Hybrid electric vehicles)
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15. Fuzzy Logic Controller for
Boost Dc-Dc Converter:-
An analysis of boost converter circuit revealed that the inductor current
plays significant task in dynamic response of boost converter.
Additionally, it can provide the storage energy information in the
converter. Thus, any changes on the inductor current may affect output
voltage and output voltage will provide steady state condition information
of converter. However, the three main parameters need to be considered
when designing boost converters are power switch, inductor and capacitor.
In this objective to achieve the desired output voltage and the stability is
by designing the power switch.
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16. CONCLUSION:-
Design of a fuzzy logic controller on control boost dc-dc converter by using
MATLAB has been successfully achieved. A simple algorithm based on the
prediction of fuzzy logic controller, possibly using the fuzzy rules parameter, is
showing to be more convenient than the circuit without fuzzy. As the 20 V input on
the output voltage for the closed loop circuit (with fuzzy logic controller) with 0%
overshoot shows the better performance compared to the open loop circuit (without
fuzzy logic controller) whereby it has 80% overshoot. Moreover, the value of the
output current also improving corresponds to the system and produce a constant
value for the output current as 0.5 A. This scenario would not happen to the output
current of the open loop circuit. Using a closed loop circuit with fuzzy logic
controller, it is confirmed that the boost dc-dc converter gives a value of output
voltage exactly as circuit requirement. Hence, the closed loop circuit of boost dc-dc
converter controlled that by fuzzy logic controller confirmed the methodology and
requirement of the proposed approach. These studies could solve many types of
problems regardless on stability because as we know that fuzzy logic controller is an
intelligent controller to their appliances.
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17. Department of Electrical Engineering