Aalborg Universitet
Use of a Series Voltage Compensator for Reduction of the DC-Link Capacitance in a
Capacitor-Supported System
Wang, Huai; Chung, Henry Shu-Hung; Liu, Wenchao
Published in:
I E E E Transactions on Power Electronics
DOI (link to publication from Publisher):
10.1109/TPEL.2013.2262057
Publication date:
2014
Document Version
Accepted author manuscript, peer reviewed version
Link to publication from Aalborg University
Citation for published version (APA):
Wang, H., Chung, H. S-H., & Liu, W. (2014). Use of a Series Voltage Compensator for Reduction of the DC-Link
Capacitance in a Capacitor-Supported System. I E E E Transactions on Power Electronics, 29(3), 1163-1175.
https://doi.org/10.1109/TPEL.2013.2262057
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Digital Object Identifier (DOI): 10.1109/TPEL.2013.2262057
IEEE Transactions on Power Electronics (in Press), online publication: 07 May 2013.
Use of a Series Voltage Compensator for Reduction of the DC-Link Capacitance in a
Capacitor-Supported System
Huai Wang
Henry Shu-Hung Chung
Wenchao Liu
Suggested Citation
H. Wang, H. S. H. Chung, and W. Liu, "A new concept of high-voltage DC–DC conversion using
asymmetric voltage distribution on the switch pairs and hybrid ZVS–ZCS scheme," IEEE Trans. on
Power Electron., (in press). Online access: http://dx.doi.org/10.1109/TPEL.2013.2262057
Title : Use of a Series Voltage Compensator for Reduction of the DC-Link
Capacitance in a Capacitor-Supported System
Authors : Huai WANG*, Member, IEEE
Henry Shu-hung CHUNG
†
(Corresponding author), Senior Member, IEEE
Wenchao LIU
†
Address : * Center of Reliable Power Electronics (CORPE)
Department of Energy Technology
Aalborg University
Pontoppidanstraede 101, DK-9220 Aalborg
Denmark
†
Centre for Smart Energy Conversion and Utilization Research (CSCR)
City University of Hong Kong
Tat Chee Avenue, Kowloon Tong
Kowloon, Hong Kong
Tel. : (852) 3442 7807
Email : eeshc@cityu.edu.hk
1
Use of a Series Voltage Compensator for Reduction of the
DC-Link Capacitance in a Capacitor-Supported System
Huai WANG*, Henry Shu-hung CHUNG
†
and Wenchao LIU
†
Abstract - A technique for reduction of the dc-link capacitance in a capacitor-supported system is
presented. The concept is based on connecting a voltage source in series with the dc bus line to
compensate the ripple voltage on the dc-link capacitor, so as to make the output have a near zero
ripple voltage. Since the voltage compensator processes small ripple voltage on the dc link and
reactive power only, it can be implemented with low-voltage devices. The overall required
energy storage of the dc-link, formed by a reduced value of dc-link capacitor and the voltage
compensator, is reduced, allowing the replacement of popularly used electrolytic capacitors with
alternatives of longer lifetime, like power film capacitors, or extending the system lifetime even
if there is a significant reduction in the capacitance of electrolytic capacitors due to the aging
effect. Comprehensive analysis on the static and dynamic characteristics of the system, and
hold-up time requirement will be discussed. The proposed technique is exemplified on an ac-dc-
dc power conversion system. Theoretical predictions are favorably verified by experimental
results.
Keywords- dc-link capacitor, power conversion system, capacitance reduction, voltage
compensator
2
NOMENCLATURE
C
Dc-link capacitor
DC
C
Input capacitor of the voltage compensator
f
L
Output filter inductance of the voltage compensator
f
C
Output filter capacitance of the voltage compensator
ab
v
Output voltage of the voltage compensator
ab
V
Amplitude of
ab
v
,ab rms
V
Root-mean-square value of
ab
v
C
v
Dc-link voltage
C
V
Dc component of
C
v
(0)
C
v
Voltage of
C
v
in the event of an input power outage of the front-end converter
[
(0)
C
v
=
C
V
-
||
C
v'
]
C
v'
Ac component of
C
v
,Crms
V'
Root-mean-square value of
C
v'
||
C
v'
Amplitude of
C
v'
con
v
Control signal in the control stage of the voltage compensator
con
V
Amplitude of
con
v
d
v
Output voltage of the dc-link module
,mind
V
Specified minimum dc-link voltage during the hold-up time period
D
V
Dc component of
d
v
||
d
v'
Amplitude of the voltage ripple component of
d
v
DC
v
Input voltage of the voltage compensator
3
