In order to improve the output efficiency of solar cells and to extend the life span of batteries, the input currents of converters are required to be continuous. If low output voltage ripple is required at the same time, it is obvious that the application of basic twoorder converters (such as Buck and Boost derived converters) will not be good enough. In this paper, a lot of nonisolated pushpull converters (NIPPCs) with continuous current will be introduced due to their lower current stress, higher efficiency and better EMC performance. By decomposing the converters into pushpull cells, inductor and freewheeling diodes, two families of NIPPCs based on single inductor and coupled inductor separately are systematically generated. Furthermore, characteristics analyses for some of the generated converters are also shown in this paper. Finally, two prototypes based on the corresponding typical topologies are built in the lab to verify the theoretical outcomes.
I. INTRODUCTION
In order to improve the output efficiency of solar cells and to extend the life span of batteries, converters with continuous input current are required in solarbattery power systems
[1]
,
[2]
. Therefore, Buck derived converters are not suitable for these power systems, as can be seen from the input current waveform shown in
Fig.1
(a). Boost derived converters can be chosen in these systems, but the output current is discontinuous. If the requirements for the output voltage ripple are very strict, these topologies are not suitable. To solve these problems, an LC (or a large C) filter should be added to basic secondorder converters
[3]

[5]
(such as Buck and Boost derived converters). This will make the current in the LC filter side (Refer to
Fig.1
(b)) continuous. However, this will add the system cost, weight and volume. In addition it will accentuate electrolytic capacitor reliability and electrical resonance issues. These shortcomings can be circumvented if the converter draws continuous and controllable current at the input and output stages
[6]
,
[7]
. The peak and the RMS values of the current through each device in the continuous current converters are reduced. As a result, low current stress of the devices and good EMC performance can be achieved.
Input current of (a) Buck derived converters (b) Buck derived converters with LC filter (c) highorder converters (b) nonisolated pushpull converters.
In order to achieve continuous current, adding another inductor and capacitor into these basic secondorder converters is a possible method.
[8]

[10]
introduce a family of fourthorder converters with continuous current. Superbuck and Superboost converters are typical of many of these. The waveforms of the input and output current are triangular, as shown in
Fig.1
(c). From the smallsignal mathematical model, it can be seen that they are fourthorder because they contain four storage elements. These converters are hard to design due to the high order feature and the right half phase zero (RHPZ).
Another improvement method is to introduce a transformer and several freewheeling diodes into a nonisolated DC/DC converter. This can provide a current path to the output capacitor when all of the switches are off. Due to their simple circuit configuration, the isolated pushpull converters are widely used in dc power supplies. As a result, nonisolated pushpull converters with continuous current (NIPPCs) are proposed. Add on smart
[11]

[15]
and Weinberg
[15]

[18]
converters are typical of many of these. When compared with the converters mentioned in
[8]

[10]
, the NIPPCs have complex circuit configurations, but they have many other advantages. From the smallsignal mathematical model, it is a typical secondorder system without the RHPZ. The continuous current allows for an excellent output voltage quality
[11]

[18]
. The bias magnetic problem will not be seriously deteriorated due to the inductor which is connected between the power supply and the transformer.
The objective of this paper is to propose a systematic method to synthesize NIPPCs. Two families of NIPPCs are considered. The first one is generated by a single inductor and the second one is generated by a coupled inductor. When compared to the topologies in
[11]

[18]
, multiple voltage gain styles will appear in the generated topologies, which is suitable for the wide range battery voltage. Some of the novel generated converters have high efficiency, high power density and excellent output voltage quality. In addition, the input current of the Weinberg converter
[15]

[18]
is shown in
Fig. 1
(d), which is pulsating with twolevel value. Similarly, the input or output current of the other generated NIPPC topologies are pulsating with twolevel value as well. The difference between the high and lowlevel values of the current become smaller, which results in a compact size for the filter.
II. WEINBERG CONVERTER
The Weinberg converter
[15]

[18]
is a typical example of the NIPPC. The circuit configuration and key waveforms are sketched in
Fig.2
. Suppose that the selfinductances in the primary and secondary are
L
_{NP1}
and
L
_{NS1}
, respectively. To achieve a lowripple output current,
N
_{P1}
=
N
_{S1}
,
N_{P}
=
N_{S}
,
L
_{NP1}
=
L
_{NS1}
=
L
_{1}
and the mutual inductance coefficient is 1. When
Q
_{1}
or
Q
_{2}
is on, equations (1) and (2) are satisfied; when
Q
_{1}
and
Q
_{2}
are off, equations (3) and (4) are satisfied.
D
is defined as the switch duty ratio. While considering the voltagesecond balance of the inductor, the voltage gain can be derived as equation (5). From
Fig.2
(a), it can be seen that the NIPPC is composed of an inductor, a pushpull cell and additional freewheeling diodes.
Weinberg converter’s (a) main circuit (b) waveforms of v_{gs}, i_{in} and i_{out}.
III. BASIC AND DERIVED NONISOLATED PUSHPULL CELLS
The function of pushpull cell is to provide a pulsating current or voltage. Thus, pushpull cell consists of switch network and transformer. The secondary ground H of the classical isolated pushpull cell is connected with terminal F (shown in
Fig. 3
(a)), and it is referred to as pushpull cell I. The classical isolated pushpull cell is referred to as pushpull cell II, as shown in
Fig. 3
(b). The secondary ground H of the classical isolated pushpull cell is connected with terminal E of the two paralleled forward cells, and the fourwinding transformer can be separated into two sets of independent transformer (
N_{p}
and
N_{s}
’ constitute transformer 1, and
N_{p}
’ and
N_{s}
constitute transformer 2). However, it can be seen that the current only flows through one set of transformers when
Q
_{1}
or
Q
_{2}
is on, which allows for low power density. Therefore,
N_{s}
and
N_{s}
’ are removed and the anodes of
D
_{1}
and
D
_{2}
are connected with the drain poles of
Q
_{2}
and
Q
_{1}
, respectively, and pushpull cell III, shown in
Fig. 3
(c), is generated. The converters with continuous current generated by pushpull cell III save two windings. As a result, the power density can be improved. Due to the exchange of the primary and secondary windings with the modal changes, these topologies are nonisolated. In order to obtain a higher voltage gain, two windings are inserted between the transformer and the switches, and pushpull cell IV, shown in
Fig. 3
(d), is generated. When two windings are added between the transformer and diode, pushpull cell V is generated as shown in
Fig. 3
(e).
Derivation process of five nonisolated pushpull cells.
IV. SYNTHESIS OF NONISOLATED PUSHPULL CONVERTERS WITH CONTINUOUS CURRENT
By analyzing the circuit configuration of the Weinberg converter shown in
Fig. 2
, it can be concluded that this converter is derived from the classical currentfed pushpull converter. The input current of the classical currentfed pushpull converter is continuous, while its output current is discontinuous. In order to achieve continuous output current, a diode which provides a freewheeling path for the inductor current should be added into the Weinberg converter. Similarly, the existence of the input inductor will keep the input current continuous and the pushpull cell cooperating with the freewheeling diodes will make the output current continuous. Therefore, the inductor, nonisolated pushpull cell and freewheeling diode are the possible elements when building NIPPCs. In a currentfed pushpull converter, the inductor is close to the input source and the pushpull cell should be connected with a capacitor type filter in order to ensure power transfers without incompatible switching conditions. From the basic circuit theory, closing a voltagesourcecapacitor loop or opening a currentsourceinductor leads to incompatible boundary conditions at the switching instant which causes infinite current or voltage impulses. The connection style of the inductor, pushpull cell and capacitor is shown in
Fig. 4
.
Block diagram of the NIPPCs with continuous current based on single inductor generated by (a) pushpull I (b) pushpull II (c) pushpull III, IV and V.
In pushpull cell I, an additional diode needs to be added between terminals E and G in order to obtain continuous output current, and the corresponding NIPPC structure is shown in
Fig. 4
(a). If terminal H in pushpull cell II is connected with
V
_{in+}
and an additional diode is added between terminals E and G, a NIPPC can be generated as
Fig. 4
(b). For pushpull cells III, IV and V, the connection style of the inductor, pushpull cell and capacitor is shown in
Fig. 4
(c), and additional diodes are not required in these NIPPCs since the diodes of pushpull cells III, IV and V are reused as freewheeling diodes.
Provided that
N_{p}
=
N_{p}
’,
N_{s}
=
N_{s}
’, the turn ratio of the coupled inductor is
N
_{1}
=
N
_{p1}
/
N
_{s1}
, the turn ratio of the transformer is
N
_{2}
=
N_{p}
/
N_{s}
and the current flowing through the inductor when
Q
_{1}
or
Q
_{2}
is on is defined as
i
_{1}
.
D
is the duty ratio of the MOSFET.
 A. Synthesis of NonIsolated PushPull Converters with a Single Inductor
According to the above synthesis rule, five NIPPCs are generated by a single inductor and five pushpull cells.
Fig.5
shows the NIPPCs based on a single inductor and five types of pushpull cells, which are referred as Is
[15]
, IIs
[14]
, IIIs, IVs and Vs converters, respectively. The freewheeling diode
D
_{3}
should be added to produce the freewheeling bypasses for a single inductor
L
. However, for topologies IIIs, IVs and Vs, there is no need to add any freewheeling diodes because the inductor releases energy through the rectifier diodes
D
_{1}
and
D
_{2}
, which enhances the utilization of the diodes and power density.
NIPPCs synthesized by single inductor and (a) pushpull cell I (Is) (b) pushpull cell II (IIs) (c) pushpull cell III (IIIs) (d) pushpull cell IV (IVs) (d) pushpull cell V (Vs).
It should be noted that continuous current means that the current does not go to zero at any time. In the input and output currents of the NIPPCs with continuous current, one of these NIPPCs is lowripple which is similar to the inductor current and the other one is pulsating and its waveform contains twolevel value and each level is not zero.
The performances of the NIPPCs with a single inductor are shown in
Tables II
and
III
. Among them, topology IIs can realize lowripple output current while the other topologies can realize lowripple input current.
 B. Synthesis of NonIsolated PushPull Converters with a Coupled Inductor
Unlike single inductor, there are three terminals in a coupled inductor and there are two coupling modes of integrated magnetic. The terminals of the positive direction coupling mode are named A, B and C while the terminals of the negativedirection coupling mode are named A’, B’ and C’, as shown in
Fig. 6
. Similar to
Fig. 4
,
Fig. 7
shows the block diagram of the NIPPCs generated by coupled inductor. One terminal of the coupled inductor should be chosen to connect to the freewheeling diode. When compared with the NIPPCs with a single inductor, the turn ratio of the coupled inductor can be designed properly to generate more topologies with excellent characteristics.
Circuit configuration of (a) positive direction coupling inductor (b) negativedirection coupling inductor.
Block diagram of the NIPPCs with continuous current based on coupled inductor generated by (a) pushpull I (b) pushpull II (c) pushpull III, IV and V.
Coupled inductor NIPPCs synthesized by (a) pushpull cell I and configuration c1 (Ic1) (b) pushpull cell I and configuration c2 (Ic2) (c) pushpull cell I and configuration c3 (Ic3) (d) pushpull cell I and configuration c4 (Ic4) (e) pushpull cell I and configuration c5 (Ic5) (f) pushpull cell I and configuration c6 (Ic6) (g) IIc1 (h) IIc2 (i) IIc3 (j) IIc4 (k) IIc5 (l) IIc6 (m) IIIc1 (n) IIIc2 (o) IIIc3 (p) IIIc4 (q) IIIc5 (r) IIIc6 (s) IVc1 (t) IVc2 (u) IVc3 (v) IVc4 (w) IVc5 (x) IVc6 (y) Vc1 (z) Vc2 (aa) Vc3 (ab) Vc4 (ac) Vc5 (ad) Vc6.
The three terminals of coupled inductor can be connected with the external circuit in twelve ways, which are shown in
Table I
. Therefore, the NIPPCs generated by the coupled inductor are more than those of the single inductor. Since configurations c1~6 are equivalent to c12~7, respectively, thirty NIPPCs can be generated based on coupled inductor. In total, thirtyfive NIPPCs can be generated according to the synthesizing rules.
TWELVE WAYS OF CONFIGURING THREETERMINAL COUPLED INDUCTOR TO EXTERNAL CIRCUIT
TWELVE WAYS OF CONFIGURING THREETERMINAL COUPLED INDUCTOR TO EXTERNAL CIRCUIT
Due to the diversity of the ways of configuring the coupled inductor, the number of the coupled inductor topologies is more than that of the single inductor topologies. Therefore, they are classified according to the pushpull cells and the configurations of coupled inductor. For example, topology Ic2 is generated by pushpull cell I and configurations c2.
The performances of the NIPPCs with coupled inductor are shown in
Tables II
and
III
. Since the input and output currents of topologies Ic2 and Ic4 are not continuous, these topologies are not discussed here. For topology Ic3, when
Q
_{1}
and
Q
_{2}
are both off, the anode voltage of the freewheeling diode
D
is lower than the cathode voltage and the inductor cannot release its stored energy and will be saturated. As a result, this converter cannot operate normally. The NIPPCs synthesized by the other four pushpull cells and the coupled inductors based on configuration c3 (IIc3, IIIc3, IVc3 and Vc3) cannot operate normally for the same reasons. Hereafter, these five topologies are referred as quasiNIPPCs.
PERFORMANCE OF THE NIPPCS WITH LOWRIPPLE OUTPUT CURRENT (VIN=VBAT ,VOUT= 42V, DMAX =0.5)
PERFORMANCE OF THE NIPPCS WITH LOWRIPPLE OUTPUT CURRENT (VIN=VBAT ,VOUT= 42V, DMAX =0.5)
PERFORMANCE OF THE NIPPCS WITH LOWRIPPLE INPUT CURRENT (VIN = VBUS =42V, VOUT =VBAT, , DMAX =0.5)
PERFORMANCE OF THE NIPPCS WITH LOWRIPPLE INPUT CURRENT (VIN = VBUS =42V, VOUT =VBAT, , DMAX =0.5)
V. CONVERTER CHARACTERISTICS
When compared with the traditional pushpull converter, the NIPPCs take advantage of efficiency. The high efficiency is mainly reflected in the following three aspects:

1) For the traditional pushpull converter, all of the power is regulated through the MOSFET. However, for the NIPPCs, most of the power is transferred to the load directly rather than passing through the MOSFET. As a result, the switching loss is reduced dramatically and high efficiency can be easily achieved.

2) For some of the proposed topologies in this paper, the leakage inductance of the transformer reduces di/dt and the turnon loss can be neglected. The switching loss will be reduced without additional elements or a complicated control strategy.

3) The output current of the traditional pushpull converter is discontinuous while the output currents of some of the proposed topologies in this paper are lowripple. Therefore, the RMS of the capacitor current of the traditional pushpull converter is higher than the proposed topologies in this paper. The power loss which is introduced by the ESR of traditional pushpull converter is much higher.
When compared with the traditional pushpull converter, the other advantages of the NIPPCs are shown as follows:

1) The output current of the traditional pushpull converter is discontinuous while the input and output currents of NIPPCs are continuous. Continuous input and output currents result in many benefits:

 Reductions of the spike and RMS of current. As a result, MOSFETs with low current stress can be chosen and the power loss will be reduced.

 Reductions in the volume of the filter to enhance the power density and dynamic performance.

 Enhancement of the EMC.

 They are good for sensing the current accurately.

2) The right half phase zero exists in the control to output transfer function of the traditional pushpull converter. As a result, the control system is hard to design. For some of the proposed topologies in this paper, the right half phase zero does not exist in the control to output transfer function and the control system is easy to design.
Taken together, the NIPPCs are prior to the traditional pushpull converter.
For clarity, the NIPPCs and the quasiNIPPCs are listed in this paper. First, all of the topologies are proposed except for topologies Is
[15]
, IIs
[14]
, IIIc1
[13

17]
and IIIc6
[18]
. Among the thirty five topologies, topologies IIIc2, IIIc4 and IIIc6 (with lowripple input current) are equivalent to topology IIIs; topologies IVc2, IVc4 and IVc6 (with lowripple input current) are equivalent to topology IVs; and topologies Vc2, Vc4 and Vc6 (with lowripple input current) are equivalent to topology Vs. The quasi topologies and the equivalent topologies are ignored and twenty one NIPPCs can be obtained including seventeen novel topologies.
It should be noted that this paper only focuses on the NIPPCs with continuous input and output currents and that it discusses the characteristics of these topologies. When compared with the single inductor NIPPCs, the coupled inductor NIPPCs have the advantages of smaller inductor volume, higher efficiency and wider application. Due to the complexity of the coupled inductor NIPPCs, these topologies are focused on especially. Some of the conclusions are shown as follows:

1) All of the NIPPCs are based on configuration c3 of coupled inductor and cannot operate normally since the inductor cannot release its stored energy.

2) In order to obtain the same ripple current, the value of the inductor based on the negativedirection coupling mode is higher than that of the forwarddirection coupling mode. Therefore, the NIPPCs based on the forwarddirection coupling mode have higher power density.

3) The NIPPCs based on configurations c4 and c5 can only operate normally whenN1＞1. Due to the negativedirection coupling mode,N1is designed to be more than 2 to avoid too large current ripple. The current cannot flow through the primary and secondary windings simultaneously for the NIPPC based on configuration c6. As a result, the power density of this topology is higher than that of the NIPPCs based on configurations c4 and c5. For the same reason, the power loss of the coupled inductor in these two types of topologies is the lowest among all of the NIPPCs based on coupled inductor.

4) For the NIPPCs based on pushpull cells III, IV and V, in order to realize Δiout(+)=Δiout() in one equivalent period,N2=1. However, there is no such constraint for the NIPPCs based on pushpull cells I and II, soN1andN2are uncertain.

5) Among the NIPPCs based on pushpull cells III, IV and V, if the output voltage and the maximum duty ratio are confirmed, the input voltage range of the NIPPCs based on pushpull cell V is the widest while that of the NIPPCs based on pushpull cell IV is the narrowest.

6) For the coupled inductor NIPPCs based on pushpull cells III, IV and V, the NIPPCs based on configuration c2 satisfiedVct＞VD+. Therefore, the inductor releases its stored energy through the primary and secondary windings of the transformer and these topologies are equivalent to a single inductor topology. For the NIPPCs with a coupled inductor based on configurations c4 and c5,N1＞1 should be satisfied to make them operate normally. The NIPPCs based on configuration c4 are equivalent to a single inductor topology. When the input current ripple of the NIPPCs based on configuration c6 is low, they are equivalent to a single inductor topology. It should be mentioned that the single inductor topology can only realize lowripple input current.
Multiple voltage gain styles appear in the novel coupled inductor NIPPCs, for example (1+D), (1+4D) and so on, where (1+4D) is suitable for the application of a battery with wide range voltage.
Table II
shows the performance of the NIPPCs with lowripple output current. High performance of the bus voltage is needed. The voltage stress of the switches, the voltage gain, the description of the input current and the lowripple condition of
I_{out}
are shown too. The minimum value of
V_{bat}
is calculated when
V_{in}
=
V_{bat}
,
V_{out}
=42V, and
D_{max}
=0.5, and the range of the battery voltage is obtained.
Table III
shows the performance of the NIPPCs with lowripple input current. This table also shows the voltage stress of the switches, the voltage gain, the description of the output current and the lowripple condition of
I_{in}
. The maximum value of
V_{bat}
is calculated when
V_{in}
=
V_{bus}
=42V,
V_{out}
=
V_{bat,}
, and
D_{max}
=0.5, and the range of the battery voltage is obtained.
VI. EXPERIMENTAL RESULTS
In this paper, two topologies are chosen to verify the theoretical analysis, which are shown as follows.
 A Verification Based on a Prototype of Topology IIIs
Due to its simple structure, the power density of topology IIIs is prior to the other topologies. Therefore, a 500W prototype with the novel generated topology IIIs was built in the lab to verify the above theoretical analysis. The specifications are shown as follows,
V_{bat}
=45~60V,
i_{bat}
=1A~8A,
V_{bus}
=42V,
L
=45uH,
C_{o}
=600uF,
f_{s}
=100kHz,
N
_{2}
=1, MOSFET: FB260N and Diode: 30CPQ150.
Topology IIIs is shown in
Fig. 9
(a).
Fig. 9
(b) gives the experimental waveforms of
i_{in}
and
i_{out}
when
V_{bat}
=45V and
I_{bat}
=1A.
Fig. 9
(c) gives the experimental waveforms of
i_{in}
and
i_{out}
when
V_{bat}
=60V and
I_{bat}
=8A, where the input current ripple is low and the output current is pulsating where the highlevel is
i
_{1}
and the lowlevel is 0.5
i
_{1}
. The efficiency is higher than 95% in all of the cases and the maximum is 98.1%, as shown in
Fig. 9
(d).
Experimental results of (b) when V_{bat}=45V, i_{bat}=1A (c) V_{bat}=60V, i_{bat}=8A (d) efficiency curves of (a) topology IIIs.
 B Verification Based on a Prototype of Topology Vc1
In the application of
V_{bat}
=20V~32V and
V_{bus}
=42V, the high voltage gain topology will be adaptable. Topology Vc1 with a voltage gain (1+4
D
) can meet this demand among these generated topologies. Therefore, a 500W prototype was built in the lab. The specifications are shown as follows,
i_{bat}
=1A~8A,
C_{o}
=600uF,
f_{s}
=100kHz,
N_{1}
=0.5,
N_{2}
=1:1:1:1, primary self inductor
L
_{NP1}
=15uH, secondary self inductor
L
_{NS1}
=60uH, mutual inductor
L_{M}
=29.6uH, MOSFET: FB260N and Diode: 30CP
Q
_{1}
50. Topology V
_{c1}
is shown in
Fig. 10
(a).
Fig. 10
(b) gives the experimental waveforms of
i_{in}
and
i_{out}
when
V_{bat}
=20V and
I_{bat}
=8A.
Fig. 10
(c) gives the experimental waveforms of
i_{in}
and
i_{out}
when
V_{bat}
=32V and
I_{bat}
=1A. It can be seen from
Fig. 10
that the output current ripple is low, while the input current is pulsating. The highlevel of the input current is
i
_{1}
and the lowlevel is 1/3
i
_{1}
. The efficiency curves are shown in
Fig. 10
(d). The minimum efficiency is 94.8% when
V_{bat}
=20V and
I_{out}
=8A, and the maximum efficiency is 97.6% when
V_{bat}
=32V and
I_{out}
=1A. The efficiency decreases with the increase in the load current and decrease in the battery voltage.
Experimental results of (b) when V_{b}=20V, i_{out}=8A (c) when V_{bat}=32V, i_{out}=1A (d) efficiency curves of (a) topology Vc1.
VII. CONCLUSIONS
In this paper, a systematic synthesizing method for nonisolated pushpull converters (NIPPCs) with continuous current is proposed. One single inductor with five types of pushpull cells can be combined into five NIPPCs with a single inductor. Six ways of configuring the threeterminal coupled inductor to the external circuit and five types of pushpull cells can be combined to form thirty NIPPCs with a coupled inductor. Multiple voltage gain styles appear in the novel NIPPCs, such as (1+D/2), (1+2D), (1+4D) and so on, which is suitable for the application of wide range battery voltage. Lower ripple current, higher efficiency, better EMC performance of the NIPPCs with continuous current have been achieved in this paper.
Finally, two prototypes referred as IIIs and Vc1 were built in the lab to verify the converter operation.
BIO
Yan Li was born in Heilongjiang Province, China, in 1977. She received her B.S. and M.S. degrees in Electrical Engineering from Yanshan University, Qinhuangdao, China, in 1999 and 2003, respectively, and her Ph.D. degree in Electrical Engineering from Nanjing University of Aeronautics and Astronautics, Nanjing, China, in 2009. From 1999 to 2009, she was at Yanshan University. Since 2009, she has been in the School of Electrical Engineering, Beijing Jiaotong University, Beijing, China. Her current research interests include multipleinput dc/dc converters, renewable power systems, and PV gridtied systems.
Trillion Q. Zheng (M’06SM’07) was born in Jiangshan, Zhejiang Province, China, in 1964. He received his B.S. degree in Electrical Engineering from Southwest Jiaotong University, Sichuan, China, in 1986, and his M.S. and Ph.D. degrees in Electrical Engineering from Beijing Jiaotong University, Beijing, China, in 1992 and 2002, respectively. From 2003 to 2011, he served as the Dean of the School of Electrical Engineering at Beijing Jiaotong University. He is currently a University Distinguished Professor at Beijing Jiaotong University. He directs the Center for Electric Traction, founded by the Ministry of Education, China. His current research interests include power supplies and AC drives for railway traction systems, high performance and low loss power electronics systems, PV based converters and control, and active power filters and power quality correction. He holds 17 patents in China, and has published over 60 journal articles and more than 100 technical papers in conference proceedings. He is presently the Deputy Director for the council of the Beijing Society for Power Electronics and a Member of the council of China Electrotechnical Society. He received the Excellent Teacher Award from the Beijing Government (1997), and the Youth Award of Railway Science and Technology of Zhan Tianyou (2005). He was laureate of the Youth Elite of Science and Technology of the Railway Ministry of China (1998) and of the Zhongda Scholar for work in the areas of power electronics and motor drives, from the Delta Environmental and Educational Foundation (2007).
Qian Chen was born in Zhejiang Province, China, in 1987. He received his B.S. degree in Electronic Engineering from Beijing Jiaotong University, Beijing, China, in 2009. He is presently working toward his Ph.D. degree at Beijing Jiaotong University. His current research interests include power conversions and spacecraft power systems.
Quan L.
,
Wolfs P.
2008
“A review of the single phase photovoltaic module integrated converter topologies with three different DC link configurations,”
IEEE Trans. Power Electron.
23
(3)
1320 
1333
DOI : 10.1109/TPEL.2008.920883
Xue Y.
,
Chang L.
,
Kjær S. B.
2004
“Topologies of singlephase inverters for small distributed power generators: An overview,”
IEEE Trans. Power Electro.
19
(5)
1305 
1314
DOI : 10.1109/TPEL.2004.833460
Zhao B.
,
Yu Q.
,
Sun W.
2012
“Extendedphaseshift control of isolated bidirectional DC.DC converter for power distribution in microgrid,”
IEEE Trans. Power Electron.
27
(11)
4667 
4680
DOI : 10.1109/TPEL.2011.2180928
Hegazy O.
,
Mierlo J. V.
,
Lataire P.
2012
“Analysis, modeling, and implementation of a multidevice interleaved DC/DC converter for fuel cell hybrid electric vehicles,”
IEEE Trans. Power Electron.
27
(11)
4445 
4458
DOI : 10.1109/TPEL.2012.2183148
Onwuchekwa C. N.
,
Kwasinski A.
2012
“A ModifiedTimeSharing Switching Technique for MultipleInput DC.DC Converters,”
IEEE Trans. Power Electron.
27
(11)
4492 
4502
DOI : 10.1109/TPEL.2011.2180740
Williams B. W.
2013
“DCtoDC converters with continuous input and output power,”
IEEE Trans. Power Electron.
28
(5)
2307 
2316
DOI : 10.1109/TPEL.2012.2213272
Chen Q.
,
Zheng T. Q.
,
Li Y.
,
Shao T.
2013
“The effect of transformer leakage inductance on the steady state performance of pushpull based converter with continuous current,”
Journal of Power Electronics
13
(3)
13 
3
DOI : 10.6113/JPE.2013.13.3.349
Garrigos A.
,
Carrasco J. A.
,
Blanes J. M.
,
SanchisKilders E.
2006
“A power conditioning unit for high power GEO satellites based on the sequential switching shunt series regulator,”
in Proc. MELECON
1186 
1189
Soubrier L.
,
Besdel P.
,
Daubresse T.
,
Trehet E.
2008
“High performance BDR for the PCU of alpha bus,”
in Proceeding of 8th European Space Power Conference, SP661
Available:
Roinila T.
,
Hankaniemi M.
,
Suntio T.
,
Sippola M.
,
Vilkko M.
2007
“Dynamical profile of a switchedmode converter reality or imagination,”
in Proc. 29th INTELEC Conference
420 
427
Sammaljarvi T.
,
Lakhdari F.
,
Karppanen M.
,
Suntio T.
2008
“Modeling and dynamic characterization of peak current mode controlled superboost converter,”
IET Power Electronics
1
(4)
527 
536
DOI : 10.1049/ietpel:20070366
Aroca J.
,
Olsson D.
,
Maicas J.
1998
“An efficient BDR topology, able to handle a large battery voltage range,”
in Proc. 5th European Space Power Conference, SP416
Available:
Weinberg A. H.
,
Rueda Boldo P.
1992
“A high power, high frequency, DC to DC converter for space applications,”
in Proc. IEEE PESC Conference
1140 
1147
Denzinger W.
,
Dietrich W.
2005
“Generic 100V/high power bus conditioning,”
in Proc. 7th European Space Power Conference, SP589
Available:
O’Sullivian D.
,
Martin M.
1995
“Rational behind the smart regulator,”
in Proc. 4th European Space Power Conference.
SP369, Available:
47 
54
Maset E.
,
Ejea J. B.
,
Ferreres A.
2006
“Highefficiency weinberg converter for battery discharging in aerospace applications,”
in Proc. IEEE APEC Conference
1510 
1516
Maset E.
,
Ferrers A.
2005
“5kW Weinberg converter for battery discharging in highpower communications satellites,”
in Proc. IEEE PESC Conference
69 
75
Weinberg A. H.
2005
“The battery discharge of the galileo satellite test bedV2A power system using the weinberg topology,”
in Proc. 7th European Space Power Conference, SP589
Available:
O’Sullivan D.
1994
“Space power electronicsdesign drivers,”
ESA Journal
18
(1)
1 
23
Tymerski R.
,
Vorperian V.
1988
“Generation and classification of PWM dctodc converters,”
IEEE Trans. Aerosp. Electron. Syst.
24
(6)
743 
754
DOI : 10.1109/7.18641