IEEE PEDS 2011, Singapore, 5 - 8 December 2011
A New 98% Soft-Switching Full-Bridge DC-DC
Converter based on Secondary-Side LC
Resonant Principle for PV Generation Systems
Daisuke Tsukiyama*, Yasuhiko Fukuda*, Shuji Miyake*,
Saad Mekhilef**, Soon-Kurl Kwon*** and Mutsuo Nakaoka***
* Dispersed Power System Division, Daihen Corporation, Osaka, Japan
** University of Malaya, Malaysia
*** Kyungnam University, Republic of Korea/Yamaguchi University, Yamaguchi, Japan
d-tsukiyama@daihen.co.jp
Abstract — This paper is mainly concerned with the
state-of-the-art feasible development of a novel prototype
high-efficiency phase-shift soft-switching pulse modulated
full-bridge DC-DC power converter with a highfrequency power transformer, which is designed for
utility-grid tied photovoltaic (PV) power inverters. The
proposed high-frequency transformer (HFTR) link DCDC converter topology is based upon a new conceptual
secondary-side series resonant principle and its inherent
nature. All the active power switches in the HFTR
primary-side can achieve lossless capacitive snubberbased ZVS with the aid of transformer parasitic
inductances. In addition to this, passive power switches
in its secondary-side can also perform ZVS and ZCS
transitions for input voltage and load variations.
In the first place, the operation principle of the newlyproposed DC-DC converter and some remarkable
features are described in this paper on the basis of the
simulation analysis. In the second place, the 5 kW
experimental setup of the DC-DC converter treated here
is demonstrated and its experimental results are
illustrated from a practical point of view. Finally, some
comparative evaluations between simulation and
experimental data are actually discussed and considered
in this paper, together with its future works.
Index Terms---DC-DC power converter, full bridge topology, highfrequency transformer link, secondary-side LC resonant principle,
primary-side ZVS, secondary-side ZCZVS, photovoltaic generation system
I.
INTRODUCTION
In recent years, a variety of collaborated developments on
renewable, sustainable energy conversion devices
technologies and advanced power electronics have been
strongly required toward concrete realization of non-carbon
society from a global point of view. Of these relating to
energy electronics, effective utilizations of the clean PV
generating power and the energy with the aid of the latest
energy storage devices such as batteries and/or capacitors
have attracted special interest in the fields of power electronic
distributed power supply systems applications and DC
feeding smart grid. Under such conditions mentioned above,
next generation developments of high-efficiency, high-power
Fig. 1. Overview of utility-grid tied photovoltaic (PV) system with highfrequency isolation and, circuit diagram of the new phase-shift
soft-switching pulse modulated full-bridge DC-DC converter,
which is based on the secondary-side series LC resonant principle.
density and high performance solar converters have been
practically needed so far, which include high frequency
switching pulse modulated DC-DC converters and utility
interactive sinewave modulated inverters on the basis of
digital control schemes.
In particular, the front-end high-efficiency, high frequency
switching boost DC-DC power converters such as nonisolated and isolated circuit topologies have been considered
and discussed for solar power converters in order to improve
their efficiency, power density and control performances
including noise issue. The authors have proposed several
circuit topologies of high- frequency switching DC-DC highpower converter circuits operating under the conditions of
soft commutation schemes for high power industrial
applications [1-2]. In addition, the authors have also
1
978-1-4577-0001-9/11/$26.00 ©2011 IEEE
1112
developed utility-grid tied three-phase sinewave inverter
operating under the conditions of high efficiency control
strategy [3]. To further decrease the power consumption,
advanced high efficiency and high-power density softswitching DC-DC converter topology with high frequency
transformer link is proposed for a new issue on power
solution, which is based on its secondary-side LC resonant
circuit principle for the front-end solar converter in PV
generation systems.
Also, some previous researches about a variety of DC-DC
converter with high-frequency transformer are introduced to
improve their efficiency and power density [4-14]. It
includes series-resonant soft-switching DC-DC converter
with high-frequency transformer [13-14].
In these
researches, DC-DC converter utilizes the leakage inductance
of transformer for energy storing and/or soft commutation.
However, although it is useful for realizing soft switching
DC-DC converter, a large leakage inductance more than 2 μH
or presence of parasitic capacitance more than 1 μF have to
decrease magnetic coupling coefficient of the transformer.
This result leads to not only reducing the high-frequency
transformer efficiency but also increasing the surge voltage
applied to the high-frequency full bridge inverter circuit
which is introduced into this DC-DC converter with highfrequency transformer. In addition to this, it is extremely
difficult that some series resonant DC-DC converters which
utilize the leakage inductance of transformer is adopted as
high voltage and high power applications above 1 kW, due to
the reduction of power transmission efficiency from primaryside to secondary-side.
This paper presents an improved efficiency phase shift softswitching pulse modulated full-bridge DC-DC converter with
a high frequency transformer stage and front-end boost
converter cascade stage, which includes soft-switching full
bridge diode rectifier operating on the basis of the resonant
operating principle and inherent nature of the secondary-side
LC series resonant circuit. This new DC-DC power
converter suitable for solar converter can achieve not only
soft-switching transition based on ZVS in the primary-side,
but also ZVS and ZCS commutation for the full-bridge diode
rectifier in secondary-side. The operating principle of this
DC-DC converter in a periodic steady-state is described by
using switching mode equivalent circuits and simulation
analysis, along with its inherent remarkable features as
compared with conventional ones. The simulated operating
voltage and current waveforms are comparatively illustrated
in experimental ones. The actual efficiency vs. output
power characteristics and power loss analysis are
demonstrated from an experimental point of view. The
practical effectiveness of the proposed converter for PV
generation systems are confirmed and verified by means of 5
kW setup implementation and simulation analysis.
II.
operating at the secondary-side LC resonant principle. The
LC resonant components are located across the output diode
rectifier. This high frequency isolated DC-DC converter
designed for PV generation systems can operate under ZVS
condition of the primary-side active switches S1 ～ S4 in HBridge arms with the aid of lossless capacitor, leakage
inductor Ll and magnetizing inductance Lm of the twowinding high-frequency transformer with ferrite core.
On the other hand, the passive switches in the secondaryside full-bridge rectifier can also operate under a principle of
ZVS and ZCS transitions due to the secondary-side LC
resonant circuit property.
B. Principle of Converter Operation
Figure 2 illustrates the relevant voltage and current
operating waveforms during a complete switching period for
the gate driving pulse sequences. The switching operating
modes of the soft-switching full-bridge DC-DC converter
with a high frequency transformer are divided into 6
operations modes from mode 1 to mode 6 in accordance with
operational timing points from t0 to t6. As can be seen in Fig.
3, the operation principle is described with the equivalent
circuits corresponding to each operating mode.
●Mode 1 (t0～t1):
During an active state the corresponding set of the primary
switches and secondary rectifier diodes (S2, S3 and D2, D3)
conduct simultaneously so that the secondary voltage and
current have the same polarity. The output power is
delivered from the DC source to the load. Positive voltage
magnitude Vin is applied to the high-frequency transformer.
Both VS1 and VS4, the voltages across S1 and S4, respectively,
are also equal to the source voltage Vin.
●Mode 2 (t1～t2):
The turn-off signal is applied to S3 at time t1. After S3 is
turned off, VS1 begins to decrease gradually because the
capacitor paralleled with S1, previously charged to source
voltage Vin, is linearly discharging until zero level is reached.
At the same time, the capacitor paralleled with S3, previously
discharged to zero level, is linearly charging toward positive
voltage. Therefore, low-side switch S3 is able to be turned
off with ZVS due to current flowing into the capacitor
paralleled with S3. On the other hand, diode currents (iD2,
iD3) form sinusoidal wave approache to zero so that not only
D2 but also D3 can be easily turned off with extremely soft
recovery during this period.
●Mode 3 (t2～t3):
After the capacitor voltage VS1 reaches to zero, the diode
paralleled with S1 (DS1) starts to conduct and clamps voltage
on the high-side switch S1 at zero. And consequently, the
voltage across S3 is clamped at source voltage Vin. On the
other hand, the turn-off gate pulse signal is applied to S2 at
time t2. After S2 is turned off, VS4 begins to decrease
gradually because the capacitor paralleled with S4, previously
charged to source voltage Vin, is linearly discharging until zero
level is reached. At the same time, the capacitor paralleled
with S2, previously discharged to zero level, is linearly
charging toward positive voltage. Therefore, high-side
switch S2 is turned off with almost ZVS due to current flowing
into the capacitor paralleled with S3. Although all primary
switches (S1 ～ S4) are turned off, primary current is
NEW SOFT-SWITCHING DC-DC CONVERTER
A. Circuit Description
Figure 1 shows a proposed high-frequency transformer link
phase-shift soft-switching pulse modulated full-bridge DCDC converter with the front-end boost converter cascade
stage which incorporates soft-switching full bridge rectifier
2
1113
maintained
Fig. 2.
Operating voltage and current waveforms of soft-switching highfrequency link phase-shift full-bridge DC-DC converter based on the
secondary-side LC resonant principle.
3
1114
Mode 1 (t0 ≦t < t1 )
Mode 4 (t3 ≦t < t4 )
Mode 2 (t1 ≦t < t2 )
Mode 5 (t4 ≦t < t5 )
Mode 3 (t2 ≦t < t3 )
Mode 6
Fig. 3.
(t5 ≦t < t6 )
Switching mode equivalent circuits of the phase-shift soft-switching full-bridge DCDC power converter with two winding high-frequency transformer link and softswitching full-bridge rectifier.
4
1115
C. Unique Features
maintained in the same direction during this state.
●Mode 4 (t3～t4):
Similarly to Mode 3, the diode DS4 begins to flow current
and clamps voltage on the bottom switch S4 at zero after the
capacitor voltage VS1 previously reaches to zero. On the
other hand, the current through the secondary-side diodes (D1
and D4) start to flow after VD1 and VD2 are equal to zero at the
same time when both VS2 and VS3, the voltage across S2 and S3,
respectively, reach to the source voltage Vin. At the time t4,
primary current is still flow through diodes paralleled with S1
and S4 (DS1 and DS4) while the turn-on signal is applied to S1.
●Mode 5 (t4～t5):
The current through the diodes of DS1 and DS4 decreases
gradually toward zero as the secondary-side current of D1 and
D4 increases. At the time t5, Both S1 and S4 are turned on
with ZCS simultaneously.
●Mode 6 (t5～t6):
The sinusoidal resonant current flows through primaryside active switches S1, S4 and the winding in primary-side of
high-frequency transformer.
The current through
secondary-side diodes D1, D4 and the secondary-side winding
of the transformer also forms sinusoidal resonant wave as
well. The current through the primary-side is lagging
behind the voltage while the phase between the voltage and
current through the secondary-side is close to zero, because
the resonant capacitor is located between the transformer and
the full-bridge diode rectifier acts to form a leading current.
This nature is effective to improve the converter efficiency.
In other words, there is no phase difference between the
voltage and the current in the secondary-side so that diodes
set in this side are able to be turned off without generating
reverse recovery current. In addition to this, all the diodes
paralleled with the primary-side active switches utilize the
lagging current during free-wheeling states and can be turned
off with zero reverse recovery current at time t5.
(a)
S
W
1
S
W
3
S
W
2
S
W
4
1
0
.
0
.
0
.
0
.
8
6
4
S2
2
0
(b)
1
0
.
8
0
.
6
0
.
4
0
.
2
(C)
S3
S4
S2
The specific advantageous points of the proposed DC-DC
converter in Fig. 1 are as follows;
(1) Primary-side ZVS transition of all the active switches.
(2) Secondary-side ZVS and ZCS transition of all the
passive switches.
(3) Minimum reverse recovery current switching loss at
the diode full bridge stage.
(4) Higher converter efficiency realization (98%, 380 V
DC output).
(5) Flexible design of high voltage conversion ratio.
(6) Ground leakage current protection from PV panel to
power conversion circuit portion.
(7) Utilization of the high-efficiency transformer with less
M OSFET
Fu ll-bridge circuit
HFTransformer
Diode rectifier
Series resonant
in ductor and capacitor
Fig. 4. Whole exterior appearance of boost converter-fed soft-switching
full-bridge high-frequency inverter link DC-DC converter with
soft-switching full bridge rectifier based on the secondary-side
series LC resonant principle.
S1
S4
0
0
.
1
9
9
9
4
ID1*20
0
. 1
9
9
9
5
0
. 1
9
9
9
6
T
i
m
e
(
s
)
0
.
1
9
9
9
7
0
.
1
9
9
9
8
0
.
1
9
9
9
9
V_D1
400
VD1 (V)
200
iD1×20 (A)
0
(d)
600
I_S1*20
V_S1
400
VS1 (V)
iS1×20 (A)
200
0
-200
(e)
Itrans_pri
20
itr (A)
0
-20
(f)
150
100
50
0
-50
-100
I_Lout*5
0.19994
Vcap
iLout×5 (A)
Vcap (V)
0.19995
0.19996
Time (s)
Time (s)
0.19997
0.19998
0.19999
Fig. 3. Simulated results of (a) gate driving signal S1 and S3, (b) gate
driving signal S2 and S4, (c) voltage and current of D1, (d) voltage
and current of S1, (e) resonant current of high-frequency
transformer and (f) inductor current and capacitor voltage of LC
resonant circuit under the conditions of in 380 V and 5.5 kW.
Fig. 5. Two winding high-frequency isolated power transformer is set
to the DC-DC high power converter.
5
1116
leakage inductance and parasitic capacitance.
(8) High DC voltage step-up due to front-end boost
converter cascade topology.
transformer. The maximum decrease in efficiency of 0.3%
was measured over 3 kW because of increasing actually
conduction losses.
Table 1. Design specifications and circuit parameters
III. CONVERTER SIMULATION
Real time-based computer simulations were carried out in
PSIM version 9.0 to reveal the operation of this converter
under constant load conditions. Figure 3 shows the
waveform of gate driving pulse signal (a) (b), the output
rectifier (c), the MOSFET primary switch (d), transformer
secondary current (e) and voltage across the resonant
capacitor connects series with the transformer secondary (VCr)
and the inductor current which composes output filter
connected to load (iLout) (f) with 5 kW output specifications.
As shown in Fig. 3 (c), diode D1 is turned off with ZVS and
turned on with ZCS. In Fig. 3 (d), switch S1 is turned off
after iS1 reaches to zero due to the capacitor paralleled with it.
The current through the transformer forms sinusoidal wave
due to series LC resonant circuit is depicted in Fig. 3 (e).
Figure 3 (f) indicates the energy commutation between the
resonant capacitor (1/2CV2) and the resonant inductor (1/2Li2)
which is connected to the output diode rectifier.
IV. EXPERIMENTAL RESULTS AND EVALUATIONS
A 380 V input DC-5 kW soft-switching phase-shift pulse
modulation full bridge DC-DC converter with soft-switching
full bridge diode rectifier operating on the basis of the
secondary-side LC resonant topology was built and tested in
experiment. Figure 4 shows the whole appearance of the
proposed soft-switching full-bridge DC-DC converter based
on the secondary-side LC resonant principle for PV
generation systems.
The two-winding high-frequency
transformer with ferrite core which is introduced in the DCDC converter is shown in Fig. 5. The design specifications
and circuit parameters of the converter are listed in Table 1.
The measured voltage and current waveforms of this
prototype converter are illustrated in Fig. 6. Comparing Fig.
6 to Fig. 3 (c), it can be seen that these observed voltage and
current waveforms have good agreements with the simulated
ones.
The actual efficiency vs. output power characteristic is
illustrated in Fig. 7, under the conditions of constant output
voltage and some varying specifications. Observing Fig. 7,
the actual efficiency reaches maximum value of 98% around
the 3-4 kW output power ranges indicated by white-diamond
marks. Over higher output power range, the efficiency
slightly decreases mainly because the total conduction loss of
the converter increases in accordance with the load current
increase. However, 97.8% efficiency can be still measured
at 5.2 kW outputs. The actual efficiency above 97% is
measured in the range of 1-5.2 kW outputs. Figure 7 also
depicts the efficiency in black-circle marks. In this
condition, terminals of these components are connected
directly to the measuring instruments by lengthening cables
for examining losses of each component which compose the
soft-switching DC-DC converter with high-frequency
Item
Symbol
Value
Unit
DC input voltage
(from boost converter)
Vin
380
～388
V
DC output voltage
Vout
380
V
Maximum input power
Pin
5.5
kW
Switching frequency
fsw
30.6
kHz
Switching period
Ts
16.33
μs
Phase shift time
Tφ
0.95
μs
Dead time
Td
1.6
μs
Leakage inductance of
high-frequency transformer
Ll
< 1.3
μH
Magnetizing inductance of
high-frequency transformer
Lm
640
μH
Magnetic coupling coefficient of
high-frequency transformer
k
0.998
-
Inductance of output filter
(series resonant inductor)
Lout
20
μH
Capacitance of capacitors
paralleled with transistors
CS1
～CS4
5
nF
Capacitance of
input/output capacitors
Cin,
Cout
50
μF
Capacitance of
series resonant capasitor
Cr
0.88
μF
Turn ratio of
high-frequency transformer
N1 : N2
1:1
-
Item
Symbol
Product type
Primary-side
MOSFET switches
S1
～S4
FCA76N60N
Secondary-side
rectifier diodes
D1
～D4
RHRP3060
Core material of
high-frequency transformer
-
ferrite
(PQ107)
VG_S2 (10 V/Div)
VD1
VS2 (250 V/Div)
(100 V/Div)
ID1
(5 A/Div)
Fig. 6. Experimental waveforms of gate-source voltage of S2 (VG_S2, 10
V/div), drain-source voltage of S2 (VS2, 250 V/div), diode D1
current (ID1, 5 A/div) and anode-cathode voltage (VD1, 100 V/div).
6
1117
Efficiency (%)
Loss (W)
Without wiring
for measurement
99
98.5
98
97.5
97
96.5
160
120
96
95.5
95
94.5
94
93.5
93
HF-Transformer with
resonant capacitor
80
MOSFET switches
60
Vin = 380 V
fsw = 30.6 kHz
Lout = 20 µH
27.0
21.0
100
With wiring
for measurement
Rectifier + Output filter
Vin = 380 V
fsw = 30.6 kHz
Lout = 20 µH
140
24.0
2.4
4.7
3.2
12.8
15.3
24.5
28.2
26.7
31.3
0.5
1.1
1.7
2.1
2.1
4.1
20
31.0
7.7
3.2
40
36.0
12.9
19.0
73.0
81.0
59.0
41.4
0
0
1
2
3
4
5
6
7
Output Power (kW)
Fig. 7. Measured actual efficiency of the trial-produced soft-switching
full-bridge DC-DC power converter with secondary-side series
LC resonant rectifier as a function of the output power.
4.1
5.1
5.6
Fig. 9. Power loss analysis about, full-bridge inverter circuit which is
consists of MOSFET primary switches, high-frequency
transformer, and diode rectifier with output filter.
Loss (p. u.)
Efficiency (%)
3.0
Output Power (kW)
Rectifier + Output filter
Rectifier + Output Filter
1
100
0.9
99.5
99
0.8
98.5
0.7
98
97.5
97
0.6
0.5
HF-Transformer with
resonant capacitor
96.5
96
95.5
Vin = 380 V
fsw = 30.6 kHz
Lout = 20 µH
95
94.5
0.4
0.3
MOSFET switches
0.2
Total system efficiency
0.1
94
HF-Transformer with
resonant capacitor
Vin = 380 V
fsw = 30.6 kHz
Lout = 20 µH
MOSFET switches
0
0
1
2
3
4
5
6
7
0.5
Output Power (kW)
1.1
1.7
2.1
3.0
4.1
5.1
5.6
Output Power (kW)
Fig. 8. Measured actual efficiencies versus output power characteristics
of, diode rectifier with output filter (black-circle marks), highfrequency-transformer (white-triangle marks), MOSFET fullbridge inverter circuit (black-square marks) and total efficiency of
the proposed converter with cables length consideration (whitecircle marks).
Fig. 10. Power loss analysis represented by p. u. of converter components
for, full-bridge inverter circuit adopts power MOSFETs as the
primary-side switches, high-frequency transformer, and diode
rectifier with output filter.
By connecting each input/output terminal of each power
circuit component composes the phase shift soft-switching
pulse modulated full-bridge DC-DC converter with a high
frequency transformer to the measuring instrument, input
and/or output power of each component can be measured
directly so that efficiencies and losses of these components
can also be investigated. Power efficiency of each
component was measured are shown in Fig. 8 as a function of
the output power. Total efficiency (white-circle marks) in
Fig. 8 is the same as black-circle marks in Fig. 7. As shown
in Fig. 8, all elements except full-bridge inverter which is
constructed by MOSFET reach to high efficiency of 99.5%
around 4 kW or more. Although the efficiency of the
rectifier with the filter (black-circle marks) is extremely high
in the area of 0.5-2 kW, it slightly decreases as output power
becomes larger than 3 kW. The efficiency of the full-bridge
inverter shows 98.6% maximum at 3 kW and appears to
maintain almost the same value even when output power is
more increased.
Power loss analysis about components of the converter was
investigated, the result of which is illustrated in Fig, 9. As
seen in Fig. 9, the sum of these losses is increased with
increasing output power. In the experimental condition of
Vin = 380 V, total loss of the soft-switching full-bridge DCDC converter with secondary-side resonant circuit is
increased from 30.7 W to 144 W (about 4.7 times growth)
with increasing output power from 0.5 kW to 5.5 kW (11
times growth). In the MOSFET full-bridge circuit part, the
loss is increased from 24.5 W to 81 W (3.3 times growth).
Similarly, 8.8 (from 4.1 W to 36 W) and 12.9 (from 2.1 W to
27 W) values as the growth rate of power loss are calculated
about the HF-transformer and the rectifier with the output
filter, respectively.
Figure 10 shows loss ratio of elements which compose the
converter. The primary-side MOSFET transistors which
construct the full-bridge circuit in the soft-switching DC-DC
converter account for 80% of a whole consumption in the
range of 1 kW or less and shows about 60% of that at 1.6 kW
7
1118
or more. This ratio still shows 56.3% at a full-load. These
results indicate that most of the total converter loss is
obviously due to the full-bridge circuit which consists of
MOSFET switches. The loss ratio of HF-transformer
decreases from about 30% to 25% with increasing output
power, in the range of 1.6 kW or more. On the contrary, the
loss ratio of the rectifier with the filter grows from 7.5% to
18.8% due to increasing conduction loss. Comparing Fig. 7
and Fig. 10, these results indicate that the effect of increasing
loss of the rectifier with the filter on efficiency degradation of
the converter becomes more significant as output power
increases.
shifting scheme into instantaneous current control implementation,”
Power Conversion Intelligent Motion EUROPE (PCIM EUROPE 2010),
Nuremberg (Germany), May 2010.
[4] L. Zhu, “A novel soft-commutating isolated boost full-bridge ZVS-PWM
dc-dc converter for bidirectional high power applications,” IEEE
Transactions on Power Electronics, vol. 21, no. 2, pp. 422–429, Mar. 2006.
[5] R. Li, A. Pottharst, N. Frohleke, and J. Bocker, “Analysis and design of
improved isolated full-bridge bidirectional DC-DC converter,” in Proc.
IEEE PESC Conf. Rec., pp. 521–526, 2004.
[6] S. Inoue and H. Akagi, “A bidirectional isolated DC-DC converter as a core
circuit of the next-generation medium-voltage power conversion system,”
IEEE Transactions on Power Electronics, vol. 22, no. 2, pp. 535–542, Mar.
V. CONCLUSION
2007.
[7] D. Xu,C. Zhao, andH. Fan, “A PWM plus phase-shift control bidirectional
In this paper, the latest high-efficiency phase-shift softswitching transition pulse modulation DC-DC power
converter with high-frequency transformer for PV generation
systems has been presented, which is based on the secondaryside LC series resonant circuit principle.
The operation principle of this new DC-DC converter in a
steady state has been schematically described with the aid of
simulation analysis and confirmed in experiment. This new
conceptual high-frequency link is achieved by the highefficiency power conversion processing based on the
secondary-side LC resonant principle. The comparative key
operating waveforms between simulation and experimental
results have been discussed and evaluated in details. The
actual efficiency vs. output power characteristics have been
demonstrated and discussed in this paper.
Further considerations for this new conceptual softswitching DC-DC converter proposed have should be
discussed as the following topics;
DC-DC converter,” IEEE Transactions on Power Electronics, vol. 19, no.
3, pp. 666–675, May 2004.
[8] C. G. Oggier, R. Ledhold, G. O. Garcia, A. R. Oliva, J. C. Balda, and F.
Barlow, “Extending the ZVS operating range of dual active bridge highpower DC-DC converters,” in Proc. IEEE PESC 2006, pp. 1–7, Jun. 2006.
[9] F. Krismer, J. Biela, and J.W.Kolar, “Acomparative evaluation of isolated
bi-directional DC-DC converters with wide input and output voltage range,”
in Proc. IEEE IAS 2005, pp. 599–606, 2005.
[10] H. Xiao and S. Xie, “A ZVS bidirectional DC-DC converter with
phaseshift plus PWM control scheme,” IEEE Transactions on Power
Electronics, vol. 23, no. 2, pp. 813–823, Mar. 2008.
[11] H. Bai and C. Mi, “Eliminate reactive power and increase system
efficiency of isolated bidirectional dual-active-bridge DC-DC converters
using novel dual-phase-shift control,” IEEE Transactions on Power
Electronics, vol. 23, no. 6, pp. 2905–2814, Nov. 2008.
[12] S. Inoue and H. Akagi, “A bidirectional DC-DC converter for an energy
storage system with galvanic isolation,” IEEE Transactions on Power
Electonics, vol. 22, no. 6, pp. 2299–2306, Nov. 2007.
(1) The soft-switching operating ranges for some circuit
parameters, lossless snubbing capacitors dead time
setting leakage and magnetizing inductance of highfrequency transformer, and the secondary-side LC
resonant constants.
(2) SiC power MOSFETs and SiC-SBD Integration.
(3) Feasibility study of this DC-DC converter for utilitygrid tied PV generation systems.
(4) Multi-phase DC-DC converter system integration and
practical evaluation for Power Electronic Building
Block (PEBB).
[13] X. Li and A. K. S. Bhat, “Analysis and Design of High-Frequency Isolated
Dual-Bridge Series Resonant DC-DC Converter,” IEEE Transactions on
Power Electronics, vol. 25, no. 4, pp. 850-862, Nov. 2010.
[14] A. K. S. Bhat, “A Comparison of Soft-Switched DC-DC Converters for
Fuel Cell to Utility Interface Application,” IEEJ Transactions on Industry
Applications, vol. 128, no. 4, pp. 450-458, 2008.
REFERENCES
[1] K. Fathy, K. Morimoto, T. Doi, H. W. Lee, and M. Nakaoka, “An
asymmetrical switched capacitor and lossless inductor quasi-resonant
snubber-assisted ZCS-PWM DC-DC converter with high frequency Link,”
The 12th International Power Electronics and Motion Control Conference
(IPEMC 2006), Portoroz (Slovenia), Vol. 2, pp. 1-5, Aug/Sep. 2006.
[2] K. Fathy, K. Morimoto, A. N. Ahmed, H. W. Lee, and M. Nakaoka, “A
novel soft-switching PWM DC/DC converter with DC rail series switchparallel capacitor edge resonant snubber assisted by high-frequency
transformer components,” The 3rd International Conference on Power
Electronics, Machines and Drives (PEMD 2006), Dublin (Ireland), pp.
242-246, April 2006.
[3] N. Hattori, N. Morotomi, S. Miyake, and M. Nakaoka, “Utility interactive
3-phase pulse modulated PV inverter embedding neutral point voltage
8
1119