Power Quality Issues Current Harmonics By Suresh Mikkili and Anup Kumar Panda

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Power Quality Issues Current Harmonics By Suresh Mikkili and Anup Kumar Panda

Preface

Electronic equipment such as computers, battery chargers, electronic ballasts,
variable-frequency drives, and switched-mode power supplies generate perilously
harmonics and cause enormous economic loss every year. Because of
that, both power suppliers and power consumers are concerned about power
quality problems and compensation techniques. Harmonics surfaced as a
the buzzword in the 1980s and threatened the normal operation of power systems
and user equipment. Harmonics issues are of great concern to engineers
and building designers because they can do more than the distort voltage
waveforms; they can overheat a building’s wiring, cause nuisance tripping,
overheat transformer units, and cause random end-user equipment failure.
Thus, power quality (PQ) has continued to become a more serious issue. As a
result, active power filters (APFs) have gained much more attention due to
excellent harmonic and reactive power compensation in two-wire (single
phase), three-wire (three-phase
without neutral), and four-wire
(three-phase
with neutral) AC power networks with nonlinear loads.
Active power filters have been under research and development for more
than three decades and have found successful industrial applications with
varying configurations, control strategies, and solid-state
devices. However,
this is still a technology under development, and many new contributions
and new control topologies have been reported in the last few years. It is
aimed at providing a broad perspective on the status of APF technology to
researchers and application engineers dealing with power quality issues.
In Chapter 1, the importance of active power filters and solid-state
devices
is explained in detail, and APF configurations and selection considerations
of them are also presented.
In Chapter 2, proportional–integral
(PI) controller–based
shunt active filter
(SHAF) control strategies (p-q
and Id-Iq)
are discussed in detail. SHAF control
strategies for extracting three-phase
reference currents are compared, with
their performance evaluated under different source voltage conditions using
a PI controller. The performance of the control strategies has been evaluated
in terms of harmonic mitigation and DC link voltage regulation. The
detailed simulation results are presented to support the feasibility of proposed
control strategies. To validate the proposed approach, the system is
also implemented on real-time
digital simulator hardware, and adequate
results are reported for its verification.
In Chapter 3, type 1 fuzzy logic controller (FLC)–based SHAF control
strategies with different fuzzy membership functions (MFs) (trapezoidal,
triangular, and Gaussian) are developed for extracting three-phase
reference
currents, and are compared by evaluating their performance under different
source voltage conditions. The performance of the control strategies has been
xii Preface
evaluated in terms of harmonic mitigation and DC link voltage regulation.
Detailed simulation and real-time
results are presented to validate the proposed
research.
Even though type 1 FLC–based
SHAF control strategies with different
fuzzy MFs are able to mitigate the harmonics, notches are presented in the
source current. So to mitigate the harmonics perfectly, one has to choose a
perfect controller. Therefore, in Chapter 4, type 2 FLC–based
SHAF control
strategies with different fuzzy MFs (trapezoidal, triangular, and Gaussian)
are introduced. With this approach, the compensation capabilities of SHAF
are extremely good. The detailed simulation results using MATLAB®/Simulink
® software are presented to support the feasibility of the proposed
control strategies.
In Chapter 5, a specific class of digital simulator known as a real-time
simulator is introduced by answering the questions “What is real-time
simulation?” “Why is it needed?” and “How does it work?” The latest trend
in real-time
simulation consists of exporting simulation models to a field-programmable
gate array (FPGA). Today every researcher wants to develop his
or her model in real time. The steps involved for implementation of a model
from MATLAB to real time are provided in detail. The proposed type 2 FLC–based
SHAF control strategies with different fuzzy MFs are verified with a
real-time
digital simulator (OPAL-RT)
to validate the proposed research.
Last, Chapter 6 summarizes the book and looks at future work. A comparative
study of PI controllers and the proposed type 1 FLC– and type 2 FLC–based
SHAF control strategies with different fuzzy MFs using MATLAB and
a real-time
digital simulator is also presented.

Contents

Preface………………………………………………………………………………………………………..xi
Acknowledgments………………………………………………………………………………….. xiii
Authors……………………………………………………………………………………………………..xv
Abbreviations………………………………………………………………………………………… xvii
Notations………………………………………………………………………………………………… xix
1. Introduction…………………………………………………………………………………………1
1.1 Research Background………………………………………………………………….1
1.2 Power Quality Issues…………………………………………………………………..3
1.2.1 Main Causes of Poor Power Quality………………………………..4
1.2.2 Power Quality Problems………………………………………………….4
1.3 Solutions for Mitigation of Power Quality Problems……………………8
1.3.1 Classification of Power Filters………………………………………….8
1.3.1.1 Passive Filters…………………………………………………….8
1.3.1.2 Active Filters…………………………………………………… 10
1.3.1.3 Hybrid Filters………………………………………………….. 10
1.3.2 Active Filter Applications Depending on PQ Issues……… 10
1.3.3 Selection of Power Filters………………………………………………. 11
1.3.4 IEEE Standards for Limitations of Current Harmonics…. 12
1.4 Introduction to APF Technology………………………………………………. 12
1.5 Categorization of Active Power Filter……………………………………….. 14
1.5.1 Converter-Based
Categorization……………………………………. 15
1.5.2 Topology-Based
Categorization…………………………………….. 16
1.5.3 Supply System–Based
Categorization……………………………. 18
1.5.3.1 Two-Wire
APFs……………………………………………….. 18
1.5.3.2 Three-Wire
APFs…………………………………………….. 18
1.5.3.3 Four-Wire
APFs……………………………………………….20
1.6 Technical and Economic Considerations……………………………………22
1.7 Selection Considerations of APFs………………………………………………22
1.8 Introduction to Active Power Filter Control Strategies………………23
1.9 Motivation…………………………………………………………………………………25
1.10 Book Objectives…………………………………………………………………………27
1.11 Book Structure…………………………………………………………………………..28
2. Performance Analysis of SHAF Control Strategies Using
a PI Controller…………………………………………………………………………………… 31
2.1 Shunt Active Filter Basic Compensation Principle…………………….. 32
2.2 Active Power Filter Control Strategies……………………………………….33
viii Contents
2.2.1 Signal Conditioning………………………………………………………35
2.2.2 Derivation of Compensating Signals……………………………..35
2.2.2.1 Compensation in Frequency Domain………………36
2.2.2.2 Compensation in Time Domain……………………….36
2.2.3 Current Control Techniques for Derivation of Gating
Signals…………………………………………………………………………..46
2.2.3.1 Generation of Gating Signals to the Devices
of the APF………………………………………………………..49
2.3 Introduction to DC Link Voltage Regulation…………………………….. 51
2.3.1 DC Link Voltage Regulation with PI Controller……………. 51
2.4 System Performance of p-q
and Id-Iq
Control Strategies with
PI Controller Using MATLAB®/Simulink 53
2.5 System Performance of p-q
and Id-Iq
Control Strategies with
PI Controller Using a Real-Time
Digital Simulator…………………….53
2.6 Summary…………………………………………………………………………………..60
3. Performance Analysis of SHAF Control Strategies Using Type 1
FLC with Different Fuzzy MFs…………………………………………………………. 61
3.1 Type 1 Fuzzy Logic Controller………………………………………………….. 61
3.1.1 Fuzzification…………………………………………………………………. 62
3.1.2 Fuzzy Inference Systems………………………………………………. 62
3.1.2.1 Mamdani Max-Min
Composition Scheme……….64
3.1.2.2 Mamdani Max-Prod
Composition Scheme………64
3.1.3 Defuzzification………………………………………………………………64
3.1.3.1 Centroid of Area………………………………………………66
3.1.3.2 Bisector of Area………………………………………………. 67
3.1.3.3 Mean, Smallest, and Largest of Maximum………. 67
3.1.4 Design of Control Rules…………………………………………………68
3.1.4.1 Trapezoidal Membership Function………………….68
3.1.4.2 Triangular Membership Function……………………72
3.1.4.3 Gaussian Membership Function………………………75
3.1.5 Rule Base……………………………………………………………………….75
3.2 System Performance of Type 1 FLC-Based
p-q
Control
Strategy with Different Fuzzy MFs Using MATLAB…………………79
3.3 System Performance of Type 1 FLC-Based
Id-Iq
Control
Strategy with Different Fuzzy MFs Using MATLAB…………………83
3.4 System Performance of Type 1 FLC-Based
p-q
Control
Strategy with Different Fuzzy MFs Using a Real-Time
Digital Simulator………………………………………………………………………. 87
3.5 System Performance of Type 1 FLC-Based
Id-Iq
Control
Strategy with Different Fuzzy MFs Using a Real-Time
Digital Simulator………………………………………………………………………. 87
3.6 Comparative Study……………………………………………………………………94
3.7 Summary…………………………………………………………………………………..98
Contents ix
4. Performance Analysis of SHAF Control Strategies Using Type 2
FLC with Different Fuzzy MFs……………………………………………………….. 101
4.1 Introduction to Type 2 FLC…………………………………………………….. 101
4.1.1 Why Type 2 FLCs?………………………………………………………. 102
4.2 The Structure of Type 2 FLC…………………………………………………… 103
4.3 Type 2 Fuzzy Inference System with Different Fuzzy MFs……… 106
4.4 System Performance of Type 2 FLC-Based
p-q
Control
Strategy with Different Fuzzy MFs Using MATLAB®…………….. 110
4.5 System Performance of Type 2 FLC-Based
Id-Iq
Control
Strategy with Different Fuzzy MFs Using MATLAB………………. 110
4.6 Comparative Study…………………………………………………………………. 117
4.7 Summary………………………………………………………………………………… 118
5. Introduction to RT-LAB
and Real-Time
Implementation
of Type 2 FLC-Based
SHAF Control Strategies………………………………. 121
5.1 Introduction to RT-LAB……………………………………………………………
121
5.1.1 Why Use Real-Time
Simulation?………………………………….122
5.1.2 What Is a Real-Time
Simulation?………………………………….122
5.2 Evolution of Real-Time
Simulators………………………………………….. 123
5.3 RT-LAB
Simulator Architecture………………………………………………. 125
5.3.1 Block Diagram and Schematic Interface………………………. 125
5.3.2 Inputs and Outputs…………………………………………………….. 125
5.3.3 Simulator Configuration……………………………………………… 125
5.4 How RT-LAB
Works……………………………………………………………….. 126
5.4.1 Single-Target
Configuration………………………………………… 127
5.4.2 Distributed Target Configuration………………………………… 128
5.4.3 Simulator Solvers………………………………………………………… 129
5.4.4 RT-LAB
Simulation Development Procedure………………. 129
5.5 PCI OP5142 Configuration………………………………………………………. 130
5.5.1 Key Features……………………………………………………………….. 131
5.5.2 Technical Specifications………………………………………………. 134
5.5.3 Analog Conversion Interface……………………………………….. 134
5.6 System Performance of Type 2 FLC-Based
p-q
Control Strategy
with Different Fuzzy MFs Using a Real-Time
Digital Simulator….. 135
5.7 System Performance of Type 2 FLC-Based
Id-Iq
Control Strategy
with Different Fuzzy MFs Using a Real-Time
Digital Simulators…. 139
5.8 Comparative Study…………………………………………………………………. 143
5.9 Summary………………………………………………………………………………… 144
6. Conclusions and Future Scope………………………………………………………… 145
6.1 Conclusions…………………………………………………………………………….. 145
6.2 Future Scope…………………………………………………………………………… 147
References……………………………………………………………………………………………… 151
Index………………………………………………………………………………………………………. 161