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|Title: ||Research on high input voltage DC-DC converter with low voltage stress on switches|
|Other Titles: ||Gao shu ru dian ya di dian ya ying li zhi liu dian yuan zhi yan jiu|
|Authors: ||Song, Tingting (宋婷婷)|
|Department: ||Department of Electronic Engineering|
|Degree: ||Doctor of Philosophy|
|Issue Date: ||2008|
|Publisher: ||City University of Hong Kong|
|Subjects: ||DC-to-DC converters.|
|Notes: ||145 leaves : ill. 30 cm.|
Thesis (Ph.D.)--City University of Hong Kong, 2008.
Includes bibliographical references (leaves 138-145)
CityU Call Number: TK7872.C8 S95 2008
|Abstract: ||This thesis presents research results on high input voltage DC-DC converter with low
switch stress. The voltage stress on the primary switches is only one-third of the input
voltage, so switches of low voltage rating and thus of low on-resistance can be used. This
leads to reduced conduction loss. By applying the asymmetrical duty cycle control of threephase
DC-DC converter, the converter achieves zero-voltage-switching (ZVS) for all the
switches, the switching loss can be reduced; And by using a novel phase shift pulse width
modulation (PWM) control, the converter achieves zero-voltage and zero-current switching
(ZVZCS), reduced the circulate energy loss during the freewheeling stage and increased the
soft switching range.
The contents of this thesis are as follows:
In Chapter 1, the need of using high frequency solutions in Medium Voltage (MV)
power conversion will be discussed. The existing topologies for high input voltage DC-DC
converter will be compared. The suitable application range for each topology will be
reviewed. Then, the need of a converter with six primary switches and each switch has the
voltage stress of one-third of input voltage will be discussed, followed by the proposed high
voltage three-phase DC-DC converter topology.
In Chapter 2, the operating principles of the proposed converter using asymmetrical
duty cycle control will be described. Different operating topologies will be discussed. The
steady-state voltages across capacitors will be analyzed. Also the input-to-output voltage
ratio and effective duty cycle will be studied and soft switching range will be evaluated.
Moreover the small-signal model will be given. The theoretical predictions will be verified experimentally by a 5.1kWprototype with simplified design procedures
In Chapter 3, Control strategies for the three-phase DC-DC converter will be
discussed and a novel symmetrical phase shift PWM control strategy will be proposed for
ZVZCS of the three-phase converter. The operating principles will be discussed. The
steady-state output current distribution and effective duty cycle will be analyzed, and the
soft-switching range for the three switching pairs will be given. The theoretical predictions
will be verified experimentally by a 2.2kW prototype.
In Chapter 4, a novel energy-state plane will be proposed for the control of boostderived
converters which appear as the input stage of the DC-DC converter to improve the
input power factor. The operating principles will be derived; the large-signal and steady
state characteristics will be analysis. A boost prototype will verify the features of the new
control strategy. This method can be extended to the control of the proposed medium
voltage DC-DC converter.
In Chapter 5, conclusions of the research and some suggestions for further studies will
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b2268778|
|Appears in Collections:||EE - Doctor of Philosophy |
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