Table Of ContentPower Systems
Kyo-Beum Lee
June-Seok Lee
Reliability
Improvement
Technology for
Power Converters
Power Systems
More information about this series at http://www.springer.com/series/4622
Kyo-Beum Lee June-Seok Lee
(cid:129)
Reliability Improvement
Technology for Power
Converters
123
Kyo-Beum Lee June-Seok Lee
Department ofElectrical andComputer Korea Railroad Research Institute (KRRI)
Engineering Uiwang-si
AjouUniversity Korea (Republicof)
Suwon
Korea (Republicof)
ISSN 1612-1287 ISSN 1860-4676 (electronic)
Power Systems
ISBN978-981-10-4991-0 ISBN978-981-10-4992-7 (eBook)
DOI 10.1007/978-981-10-4992-7
LibraryofCongressControlNumber:2017943172
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Preface
Powerelectronicstechnology,whichwasusedonlyformotor drivesinthepast,is
currently being used in numerous industries including renewable energy in
householdappliances,automobiles,andenergystoragedevices.Thischangeisdue
inparttotheincreasedinterestinimprovingtheefficiencyofelectronicandelectric
devices.Themainreasonisthatresearchonpowerelectronicshasbeencarriedout
inmanyuniversitiesandresearchinstitutes,andresearchersequippedwithskillsin
thefieldofpowerelectronicshavebeenexportedacrosstheindustry.Basedonthis,
it can be said that the power electronics technology related to low- and
medium-capacitysystemshasmaturedconsiderably.Theexistingpowerelectronics
technologyhasevolvedintoahighlyreliabletechnologybasedonthedevelopment
experiences and know-how of researchers. However, due to recent increases in
energy demand within the industry, high-pressure/high-capacity systems are
required. As a result, new power electronics topologies are being developed and
studied.Therearetwohighlyrepresentativeresearchareasinthefieldofmultilevel
converters. Multilevel converters, mainly in Europe and China, have been applied
tohigh-voltage/high-capacitywindpowergeneration systems,andrelated research
is being actively conducted. In addition, the development of HVDC (high-voltage
DC)transmissionsystemsisalsoarepresentativefieldintermsoftheapplicationof
multilevelconverters.Thisbookincludesthebasicintroductionofthemostwidely
studiedandusedmultilevelconvertertopologies,anditintroducesthemostreliable
three-levelconvertertechnology,whichisthemostsimilartoatwo-levelconverter.
In addition, this book introduces reliable technology for cascaded H-bridge
invertersinthelastchapter.Three-levelconvertersandcascadedH-bridgeinverters
have been applied to high-voltage systems mainly due to the advantages of mul-
tilevel converters. The cascaded H-bridge converter is expanding its application
range to high-power and high-voltage systems. However, three-level converters
have recently been used in low voltage/medium capacity systems and have been
expanding their applications as well. Two-level converters, which have been
studied in the field of motor drives in the past, are typical topologies with high
reliability based on accumulated technology. On the other hand, although
three-levelconvertersandcascadedH-bridgeinverterhavebeenappliedinthepast.
v
vi Preface
However, since the field is narrow and there are not many cases, their
reliability-related technology is lacking. This book introduces the concept of
multilevel converters and basic knowledge of three-level converters and cascaded
H-bridge converter to students that want to study multilevel converters as well as
powerelectronicsengineerswhowanttoapplythree-levelconvertersandcascaded
H-bridge inverter to their field. They will also be introduced to techniques for
dealing with a variety of reliability-related issues.
Suwon, Korea (Republic of) Kyo-Beum Lee
Uiwang-si, Korea (Republic of) June-Seok Lee
Contents
1 Three-Level Converter Overview.... .... .... .... .... ..... .... 1
1.1 Three-Level Converters .... .... .... .... .... .... ..... .... 1
1.2 Three-Level Converter Types.... .... .... .... .... ..... .... 5
1.2.1 NPC (Neutral-Point Clamped) Converter . .... ..... .... 5
1.2.2 T-Type Three-Level Converter . .... .... .... ..... .... 6
1.2.3 Comparison Between Two-Level Converter
and NPC/T-Type Three-Level Converters. .... ..... .... 8
1.3 Three-Level Converter Operation Principle.. .... .... ..... .... 9
1.3.1 I/O Characteristics... .... .... .... .... .... ..... .... 9
1.3.2 Output Voltage of Three-Leg Three-Level Inverters.. .... 11
1.3.3 Space Vector PWM (SVPWM). .... .... .... ..... .... 12
1.3.4 Carrier-Based PWM . .... .... .... .... .... ..... .... 16
1.3.5 Neutral-Point Voltage Fluctuation... .... .... ..... .... 19
1.4 Three-Level Converter Reliability Research Field. .... ..... .... 20
1.4.1 Fault Diagnosis and Tolerance Control of Three-Level
Converters.... ..... .... .... .... .... .... ..... .... 21
1.4.2 Neutral-Point Voltage Ripple Reduction.. .... ..... .... 21
1.4.3 Leakage Current Reduction.... .... .... .... ..... .... 23
References.. .... .... .... ..... .... .... .... .... .... ..... .... 24
2 Open-Circuit Fault Detection Methods for Three-Level
Converters. .... .... .... ..... .... .... .... .... .... ..... .... 25
2.1 Switch Fault Case and Reasons .. .... .... .... .... ..... .... 25
2.2 Switch Open-Circuit Fault Detection Methods
for NPC Three-Level Inverters... .... .... .... .... ..... .... 30
2.2.1 Switch Open-Circuit Fault Detection Methods
Using Additional Devices. .... .... .... .... ..... .... 30
2.2.2 Switch Open-Circuit Fault Detection Method
Using Current Distortion.. .... .... .... .... ..... .... 31
vii
viii Contents
2.3 Switch Open-Circuit Fault Detection Methods
for NPC Three-Level Rectifiers .. .... .... .... .... ..... .... 42
2.3.1 Switch Open-Circuit Fault Detection Method Using
Additional Devices .. .... .... .... .... .... ..... .... 42
2.3.2 Switch Open-Circuit Fault Detection Method Using
Current Distortion... .... .... .... .... .... ..... .... 42
2.4 Switch Open-Circuit Fault Detection Method for T-Type
Three-Level Inverter.. ..... .... .... .... .... .... ..... .... 55
2.4.1 Switch Open-Circuit Fault Detection Method
Using Current Distortion.. .... .... .... .... ..... .... 55
2.5 Switch Open-Circuit Fault Detection Method for T-Type
Three-Level Rectifiers. ..... .... .... .... .... .... ..... .... 64
2.5.1 Switch Open-Circuit Fault Detection Method
Using Current Distortion.. .... .... .... .... ..... .... 64
References.. .... .... .... ..... .... .... .... .... .... ..... .... 72
3 Three-Level Converter Tolerant Control for Switch Faults.... .... 75
3.1 Three-Level Converter Tolerant Control in Topology
Modifications ... .... ..... .... .... .... .... .... ..... .... 76
3.1.1 Tolerant Control with Six Thyristors. .... .... ..... .... 76
3.1.2 Tolerant Control with an Additional Leg
and Thyristors. ..... .... .... .... .... .... ..... .... 76
3.1.3 Tolerant Control with Six Additional Switches. ..... .... 78
3.1.4 Other Tolerant Control Topologies.. .... .... ..... .... 79
3.2 Three-Level Converter Tolerant Control Using Modifications
of the Switching Method ... .... .... .... .... .... ..... .... 80
3.2.1 Open-Circuit Faults in NPC Three-Level
and T-Type Three-Level Converters. .... .... ..... .... 81
3.2.2 Tolerant Control for S and S Open-Circuit Faults. .... 82
x2 x3
3.2.3 Tolerant Control for S and S Open-Circuit Fault.. .... 109
x1 x4
References.. .... .... .... ..... .... .... .... .... .... ..... .... 137
4 Neutral-Point Voltage Reduction .... .... .... .... .... ..... .... 139
4.1 Neutral-Point Voltage of Three-Level Converters. .... ..... .... 139
4.2 Neutral-Point AC Ripple Voltage Reduction Methods . ..... .... 144
4.2.1 Dwell Time Compensation for Neutral-Point Voltage
Reduction in the Carrier Based PWM Method . ..... .... 144
4.2.2 Dwell Time Compensation for Neutral-Point Voltage
Reduction in SVPWM Method. .... .... .... ..... .... 154
References.. .... .... .... ..... .... .... .... .... .... ..... .... 176
Contents ix
5 Leakage Current Reduction.... .... .... .... .... .... ..... .... 179
5.1 Leakage Current Analysis... .... .... .... .... .... ..... .... 179
5.1.1 Main Reason for Leakage Current .. .... .... ..... .... 179
5.1.2 Leakage Current Reduction Methods in H-Bridge
and Two-Level Converters .... .... .... .... ..... .... 180
5.1.3 Three-Level Converters... .... .... .... .... ..... .... 182
References.. .... .... .... ..... .... .... .... .... .... ..... .... 204
6 Switch Fault Diagnosis and Tolerant Control in Cascaded
H-Bridge Multilevel Inverters... .... .... .... .... .... ..... .... 207
6.1 Cascaded H-Bridge Multilevel Inverters.... .... .... ..... .... 208
6.1.1 Configuration . ..... .... .... .... .... .... ..... .... 208
6.1.2 PWM Methods ..... .... .... .... .... .... ..... .... 211
6.2 Fault Diagnosis.. .... ..... .... .... .... .... .... ..... .... 213
6.2.1 Fault Diagnosis Using Additional Devices .... ..... .... 213
6.2.2 Fault Diagnosis Using Currents. .... .... .... ..... .... 215
6.3 Fault Tolerant Control ..... .... .... .... .... .... ..... .... 232
References.. .... .... .... ..... .... .... .... .... .... ..... .... 250
