3030
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 54, NO. 6, DECEMBER 2007
Performance Evaluation of a Novel Hybrid
Multipulse Rectifier for Utility Interface
of Power Electronic Converters
Luiz Carlos Gomes de Freitas, Marcelo Godoy Simões, Senior Member, IEEE,
Carlos Alberto Canesin, Member, IEEE, and Luiz Carlos de Freitas
Abstract—This paper presents an improved analysis of a novel
Programmable Power-factor-corrected-Based Hybrid Multipulse
Power Rectifier (PFC-HMPR) for utility interface of power electronic converters. The proposed hybrid multipulse rectifier is composed of an ordinary three-phase six-pulse diode-bridge rectifier
(Graetz bridge) with a parallel connection of single-phase switched
converters in each three-phase rectifier leg. In this paper, the authors present a complete discussion about the controlled rectifiers’
power contribution and also a complete analysis concerning the
total harmonic distortion of current that can be achieved when the
proposed converter operates as a conventional 12-pulse rectifier.
The mathematical analysis presented in this paper corroborate,
with detailed equations, the experimental results of two 6-kW
prototypes implemented in a laboratory.
Index Terms—AC motor drives, high power drives for trolleybus systems, high power factor three-phase rectifiers, multipulse
rectifiers, tractions applications, 12-pulse rectifiers.
I. I NTRODUCTION
D
IODE-BRIDGE rectifiers are very important for several
industrial and home equipment in order to feed the intermediate dc link usually used in electronic topologies. However,
ordinary diode-bridge rectifiers do not meet harmonic-content
restrictions as imposed by IEC61000-3-4 [1]–[3]. Therefore,
complex power-factor correction structures or expensive bulky
linear filters must be installed to compensate for such harmonic
contamination. There has been tremendous interest in achieving a low harmonic distortion in ac–dc converters through
programmable power-factor front-end rectifiers or some other
techniques [4], [5].
The current state of art suggests the application of multipulse converters for achieving cancellation of input harmonic
current at the need of magnetic circuits such as phase-shifting
transformers, interphase transformers (IPTs), current-balancing
Manuscript received March 8, 2007; revised July 31, 2007. This work was
supported by CAPES, FAPEMIG, CNPq, FAPESP, and the National Science
Foundation.
L. C. G. de Freitas is with the Industry Division, Federal Center of Technological Education of Goiás (CEFET-GO/UnED-Jataí), Jataí, GO 75804020,
Brazil (e-mail: lcgfreitas@yahoo.com.br).
M. G. Simões is with the Engineering Division, Colorado School of Mines
(CSM), Golden, CO 80401-1887 USA (e-mail: mgsimoes@ieee.org).
C. A. Canesin is with the Faculty of Engineering, São Paulo State University (UNESP), Ilha Solteira, SP 15385-000, Brazil (e-mail: canesin@dee.feis.
unesp.br).
L. C. de Freitas is with the Faculty of Electrical Engineering (FEELT),
Federal University of Uberlandia (UFU), Uberlandia, MG 38400-902, Brazil
(e-mail: freitas@ufu.br).
Digital Object Identifier 10.1109/TIE.2007.907004
transformers, and harmonic-blocking transformers with the obvious drawback of the complex design of heavy, bulky, and
expensive custom-made equipment [4]–[13].
Elimination of IPTs is particularly desirable when there are
preexisting harmonic voltages in the three-phase power source.
This is because preexisting harmonic voltages cause changes in
the dc output voltage, which greatly complicates the design of
IPTs [4], [14]. Therefore, many authors have presented great
works focusing on the development of transformer concepts for
multipulse-rectifier applications in order to improve the current
sharing between two rectifiers’ bridges and/or to eliminate the
necessity of IPTs [4], [5], [7], [9], [10], [12], [13]. However,
despite the robustness of these structures, the volume, weight,
and size are still limiting factors.
Hence, there has been great interest in achieving autotransformer arrangements to be used in rectifier applications in
order to reduce the volume, weight, and size of the multipulserectifier structures [4], [5], [7], [13], [15]–[17]. It must be
emphasized that, in some cases, since autotransformers are used
to feed noncontrolled rectifiers, IPTs become an essential element in order to assure the correct operation of the multipulserectifier structure.
An alternative technique that provides the correct operation
of multipulse rectifier fed through an autotransformer without
using IPTs consists of the connection of switched converters in
the dc side of each three-phase diode-bridge rectifier in order to
guarantee the correct current sharing among the rectifier units.
For example, in a 12-pulse rectifier, there will be two switched
converters rated at 50% of the total output power, or in an
18-pulse rectifier, there will be three switched converters rated
at 33% of the total output power, and so on. However, in highpower levels (up to 50 kW), the efficiency and circuit complexities of the switched converters become an another challenge to
overcome in the field of multipulse rectifiers [10], [18].
On the other hand, a novel approach that overcomes many
disadvantages in the field of multipulse rectifiers is presented
and fully evaluated in this paper [19], [20]. The proposed structure was obtained, associating a switched converter in parallel
with each leg of a three-phase six-pulse diode rectifier resulting in a programmable input-line current waveform structure,
which is shown in Fig. 1. The system is capable of providing
ultraclean power without the need of phase-shifting transformers, IPTs, current-balancing transformers, or harmonicblocking transformers, and it was named Programmable
PFC-Based Hybrid Multipulse Power Rectifier (PFC-HMPR).
0278-0046/$25.00 © 2007 IEEE
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Fig. 1.
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Simplified diagram of the PFC-HMPR.
The power rating of the parallel converters (Rect-2) is a
fraction of the total output power, varying from 20% to around
45% of the rated power, depending on the desired THDI that
must be achieved. It will be fully demonstrated in this paper.
The proposed hybrid multipulse rectifier is a structure that
combines the robustness, simplicity, and reliability of the sixpulse diode-bridge rectifier with the high-frequency operation
of the controlled rectifiers, and therefore, the volume, weight,
and size of the proposed structure are extremely reduced with
higher efficiency. Thus, the rated power can be increased
up to 50 kW, which cannot be achieved with ordinary unit
power-factor three-phase pulsewidth-modulation (PWM) rectifiers [22]–[24].
Thus, this paper presents a performance evaluation of the
proposed PFC-HMPR operating as a 12-pulse rectifier, including a mathematical analysis that corroborates the experimental
results of the two prototypes rated at 6 kW.
II. P RINCIPLE OF O PERATION
From the combination of the input-line currents of Rect-1
(current ia1 ) and Rect-2 (current ia2 ), the input-line current of
the proposed PFC-HMPR (current ia(in) ) is obtained (line A for
instance). Hence
ia(in) (t) = ia1 (t) + ia2 (t)
(1)
ib(in) (t) = ib1 (t) + ib2 (t)
(2)
ic(in) (t) = ic1 (t) + ic2 (t)
(3)
where
ia(in) (t), ib(in) (t), ic(in) (t)
ia1 (t), ib1 (t), ic1 (t)
ia2 (t), ib2 (t), ic2 (t)
ac input-line currents of
PFC-HMPR;
ac input-line currents of Rect-1;
ac input-line currents of Rect-2.
Fig. 2. Theoretical waveforms—12-pulse composition.
Fig. 2 shows the principle of constructing an input-line current ia(in) through two components ia1 and ia2 that are obtained
when the PFC-HMPR topology operates as a conventional
three-phase 12-pulse rectifier. The ia2 current waveform is the
main controller of the overall characteristic of the ia(in) waveform; therefore, the PFC-HMPR allows the improvement of the
input-line current total harmonic distortion (THD) through a
very simple technique.
In order to achieve the same operational characteristics of
a conventional 12-pulse rectifier, which means to provide an
ac input-line current with harmonic components of 12n ± 1
orders, the peak value of current ia2 (I2P ) must be proportional to the peak value of current ia1 (I1P ), as demonstrated
in Section III. In this case, the switched converters’ power
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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 54, NO. 6, DECEMBER 2007
Fig. 3. Theoretical waveforms—Sinusoidal composition.
contribution will be around 20% of the total output power
(6.67% for each switched converter).
Concerning the operational characteristics of the proposed
PFC-HMPR, it is also important to emphasize that the
switched-converter-imposed current can assume any waveform,
depending on the final ac input-line current waveform that is desired. This operational characteristic assures higher flexibility,
which means that a sinusoidal input-line current waveform [21]
can be achieved, providing THDI as low as it can be achieved
in 24-pulse rectifiers [12].
In this context, the current ia2 can be imposed, as shown in
Fig. 3. Therefore, the combination of the currents ia1 and ia2
results in a sinusoidal input-line current just as ordinary unit
power-factor three-phase PWM rectifiers can provide; however,
complex control strategies, which contribute to increase its cost
and implementation difficulties, are not needed [22]–[24].
In conclusion, the lower is the desired THDI , and the higher
is the switched converters’ power contribution. Thus, in the
extreme, in order to achieve a sinusoidal input-line current, the
switched converters’ power contribution will be around 45% of
the total output power (15% for each switched converter), as
demonstrated in [21].
The design of the switched converters can be optimized in
order to mitigate its power contribution and, at the same time, to
achieve the desired THDI assuring higher overall efficiency. It
is important to emphasize that the switched converters (Rect-2)
provide active power to the load; hence, the proposed structure
cannot be classified as static compensators, which makes this
proposal unique.
III. H ARMONIC A NALYSIS OF THE 12-P ULSE
I NPUT -L INE C URRENT
In order to reduce the THDI , the PFC-HMPR is capable
of operating with 12-pulse or sinusoidal ac currents. When
operating with sinusoidal input-line current, the PFC-HMPR
presents its better performance related to the THDI , meeting
all harmonic-content restrictions imposed by IEC61000-3-4;
hence, a harmonic analysis of the input-line current waveform
is not needed. However, when operating as a 12-pulse rectifier,
this kind of analysis is necessary since the elimination of
harmonic components such as the 5th, 7th, 17th, and 19th
depends on the peak value of the switched converters’ inputline currents ia2 , ib2 , and ic2 .
Since the input currents of Rect-1 and Rect-2 are continuous
functions that repeat periodically, therefore, using the Fourier
theorem, it is possible to prove that the PFC-HMPR input-line
current presents the same harmonic spectrum of a conventional
12-pulse rectifier (12n ± 1). As it is well known, the frequency
domain representation of current ia1 is given by
√
1
2 3
1
I1P cos(ωt)− cos(5ωt)+ cos(7ωt)
ia1 (ωt) =
π
5
7
1
1
− cos(11ωt)+ cos(13ωt)
11
13
1
1
− cos(17ωt)+ cos(19ωt)
17
19
1
1
− cos(23ωt)+ cos(25ωt)+· · · .
23
25
(4)
The frequency-domain representation of current ia2 is given by
∞
1
4
cos(nωt)
ia2 (ωt) = (kI1P ) 0.63
π
n
n=1,13,25,...
+ 2.36
− 2.36
∞
n=5,17,...
∞
n=7,19,...
1
cos(nωt)
n
1
cos(nωt)
n
1
cos(nωt) . (5)
− 0.63
n
n=11,23,...
∞
A. Harmonic Components of the PFC-HMPR
Input-Line Current—ia(in)
Using Matlab software, it was possible to obtain the timedomain representation of current ia(in) , which is obtained from
the combination of (4) and (5). Thus, it is shown in Fig. 4 the
waveform of current ia(in) taking into account the harmonic
components of order n = 200.
B. Total Harmonic Distortion of the AC Input Current—ia(in)
In order to illustrate the PFC-HMPR performance related
to the THDI achieved when a 12-pulse current is imposed in
the ac system, the Matlab software was used to calculate the
final THDI of the input-line current as a function of k. Thus,
in Fig. 5, one can observe that the minimum THDI (around
13.4%) is achieved when the peak value of current ia2 is around
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DE FREITAS et al.: EVALUATION OF A HYBRID MULTIPULSE RECTIFIER FOR UTILITY INTERFACE
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Fig. 6. Harmonic spectrum of the PFC-HMPR input-line current operating as
a 12-pulse rectifier for 0.3 ≤ k ≤ 0.36.
IV. C HOICE OF THE S WITCHED C ONVERTERS
Fig. 4. Waveform of current ia(in) obtained through the Fourier of currents
ia1 and ia2 .
Fig. 5. Total harmonic distortion of the input-line current for different values
of k—12-pulse mode of operation.
33% of the peak value of current ia1 (k = 1/3). It is important
to emphasize that this value of THDI is the same result reported
in [10] and [15] where it was obtained with an 18-pulse rectifier
scheme with an autotransformer feeding three six-pulse diode
rectifiers with common load.
In conclusion, in order to prove that the input-line current
of the PFC-HMPR, operating as an ordinary 12-pulse rectifier,
presents the harmonic components of order 12n ± 1, the Matlab
software was used to combine (4) and (5) obtaining the values
shown in Fig. 6.
As one can see that, when k is around 1/3, the 5th, 7th, 17th,
and 19th harmonics assume extremely reduced levels; hence, it
can be stated that, in this mode of operation, the PFC-HMPR
input-line current is given by
∞
1
4.3I1P
cos(nωt)
cos(ωt) −
ia(in) (ωt) =
π
n
n=11,23,35,...
∞
1
+
cos(nωt) . (6)
n
n=35,25,37,...
Boost converters have been traditionally used as front-end
wave-shaping systems, but, in order to be applied as a parallel
path of three-phase six-pulse diode-bridge rectifier, nonisolated boost converters are not suitable. It means that boost
converters fed through line voltages or line-to-neutral voltages are not suitable to be used in the proposed PFC-HMPR
structure.
When boost converters are fed through a line-to-line voltage,
it is observed that, during the period of time when the input-line
voltage of the three-phase power source is higher than the dc
output voltage, the boost current keeps on increasing even when
the switch is open. In fact, when the boost switch is open and
the freewheeling diode is forward-biased connecting the path
between Rect-2 and Rect-1, the boost current flows through
the diodes of the three-phase six-pulse rectifier bridge (Rect-1),
and its control is lost, eventually impeding the desired currentwaveform composition.
On the other hand, when boost converters are fed through a
line-to-neutral voltage, it can be assured that the input voltage
will never be higher than the dc output voltage; however, the
boost current still finds a path through the negative diodes’
group of the three-phase six-pulse rectifier bridge (Rect-1)
instead of returning through the boost circuit. It was observed
even when modified boost converters were used [22].
In this context, single-ended primary inductor converter
(SEPIC) behaves naturally as an input-current source, allowing
the waveform of the input current to be imposed with a suitable
control strategy. In contrast to the boost-converter behavior,
when the switch Sn is opened (n: 1, 2, 3), the series capacitor
of the SEPIC converter assures, at any operating conditions, the
isolation of those circuits and the correspondent decrease of the
current flow through the input inductor. Thus, the imposition of
the input current does not strongly depend on the level of the dc
output voltage V0 (dc link voltage).
In order to improve the SEPIC converters’ performance,
some modifications were made, as one can observe in Fig. 7.
Each circuit differs from the normal SEPIC topology by the
presence of a split input inductor, a split capacitor, and a split
freewheeling diode. These modifications are necessary on the
account of circulating currents that exist among the SEPIC
converters when operating with a common load. The purpose
of these modifications is to avoid the circulating currents assuring the correct ac current composition. A very similar case
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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 54, NO. 6, DECEMBER 2007
Fig. 7. Proposed PFC-HMPR deploying modified SEPIC converters.
concerning parallel connection of boost converters was reported
in [22].
It should be emphasized that, when boost converters are fed
through single-phase transformers, there is a galvanic isolation,
as shown in Fig. 3. In this arrangement, the boost current is
confined to the secondary winding circuit, and the dc output
voltage is kept with an average value approximately equal to
the peak line-voltage value. This structure is able to replace the
SEPIC converters because it can be assured that the boost current will be forced to return through the boost circuit instead of
the three-phase six-pulse rectifier bridge. Hence, the control of
the boost current is no longer lost, resulting to the achievement
of the desired input-line current waveform.
As a result, the proposed concept can also be implemented,
deploying boost converters, but with the obvious drawback of
requiring extra magnetic devices, which increases the volume,
weight, and cost of the structure. The proposed PFC-HMPR
deploying boost converters is shown in Fig. 8.
It is important to emphasize that, even when using singlephase isolating transformers, the proposed PFC-HMPR deploying boost converters can still be attractive when compared to
other multipulse-rectifier structures [7], [18] since each singlephase isolating transformer must be rated at 7% (12-pulse ac
input current) of the total output active power, as described in
Section VI, or 15% (sinusoidal ac input current), as reported
in [21].
Fig. 8.
Proposed PFC-HMPR deploying boost converters.
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V. S WITCHED C ONVERTERS ’ P OWER
C ONTRIBUTION —12-P ULSE AC C URRENT
The rated power processed by each rectifier group
(Rect-1 and Rect-2) can be determined based on the peak value
of the input-line currents ia1 and ia2 , respectively (phase A for
instance). In this context, the target is to quantify the fraction of
power processed by each rectifier group in relation to the total
output power. The system is going to be considered as loss-free
and with unity input power factor. Thus
P0 = Pin =
3
VP IP
2
(7)
where
P0
total output active power;
Pin total input active power;
VP peak value of the line-to-neutral voltage;
peak value of the input-line current.
IP
The power processed by each dc–dc converter (Rect-2), when
the proposed PFC-HMPR operates as a 12-pulse rectifier, can
be determined as follows:
PDC−DC Conv.1
1
=
π
π/6
VP sin(ωt) · I2P dωt
2π/3
VP sin(ωt) · I2P dωt
π/3
π
+
VP sin(ωt) · I2P dωt
(8)
5π/6
where I2P is the peak value of the switched-converter input-line
current.
As it was demonstrated in the last section, the switchedconverter-imposed current must be proportional to the sixpulse diode-bridge-rectifier input current in order to achieve the
lowest THDI ; thus, the peak value of the switched-converter
input-line current is expressed by
I2P = k · I1P
(9)
where
I1P peak value of the six-pulse diode-bridge-rectifier
input-line current;
k
constant.
Therefore, the switched-converters’ power contribution is
given by
1.268
PRect-2 = 3 · VP · IP ·
.
(10)
π
The power rating of the switched converters (PRect−2 ) in
relation to the total output power (P0 ) can be determined as
3 · VP · IP · 1.268
PRect-2
π
=
.
P0
3/2 · VP · IP
Since the peak value of the input-line current is
IP = I1P + I2P = I1P (k + 1).
(12)
the power contribution of the switched converters can be
expressed as
k
PRect-2
= 2.536
.
(13)
P0
π · (k + 1)
0
+
Fig. 9. Representation of the PFC-HMPR performance concerning the
switched converters’ power contribution—12-pulse ac current.
(11)
Provided that the switched converters operate as current
sources with a suitable imposed current and that the rated power
processed by each one is determined based on the peak value of
the imposed input-line currents (ia2 , ib2 , and ic2 ), the power
rating of Rect-1 is given by
PRect-1 = P0 − PRect-2 .
(14)
In order to prove the accuracy of (13) and (14), the Matlab
software was used to illustrate the performance of each rectifier
group (Rect-1 and Rect-2). Thus, one can observe in Fig. 9
that, when operating as an ordinary 12-pulse rectifier, for
0.33 ≤ k ≤ 0.36, the power contribution of Rect-2 is around
20% of the total output power (6.67% for each switched
converter).
As one can observe, the operation regions for 0.3 ≤ k ≤ 0.36
maximize the six-pulse diode-bridge-rectifier power contribution and minimize the switched converters’ power contribution.
The other operation regions must be avoided so that the lowest
THDI and the minimum switched converters’ power contribution can be assured.
VI. E XPERIMENTAL A NALYSIS —PFC-HMPR
O PERATING AS A 12-P ULSE R ECTIFIER
A. Control Strategy
The experimental setup was built using analog gate circuitry.
Fig. 10 shows a simplified block diagram of the electronic
circuit used in the experimental setup.
As one can observe, a sample of the input line-to-neutral
voltage is rectified and compared with two dc voltage levels
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IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 54, NO. 6, DECEMBER 2007
Fig. 10. Simplified diagram block of the PWM control strategy in closed loop—12-pulse ac current.
TABLE I
PROTOTYPE PARAMETERS—PFC-HMPR—12-PULSE AC CURRENT
TABLE II
SUMMARY OF EXPERIMENTAL RESULTS OF THE
PFC-HMPR—12-PULSE AC CURRENT
for the pulse generator circuit. The output of the comparators is
connected to an OR gate, resulting to a pulsed output voltage
with a width equal to π/3 and an amplitude equal to the
comparator supply voltage.
Therefore, the reference current signal is filtered and reduced
to unity value in order to be applied to the input of the
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Fig. 11. (a) Prototype of the PFC-HMPR deploying modified SEPIC converters. (b) Modified SEPIC converters.
Fig. 12. Main experimental results of the PFC-HMPR—operating as a 12-pulse rectifier—deploying modified SEPIC converters. (a) Input-line current of
Rect-1/Phase A. (b) Input-line current of Rect-2/Phase A. (c) Input-line current and line-to-neutral voltage of PFC-HMPR/Phase A. (d) Input-line currents of
PFC-HMPR.
signal-multiplier circuit. The signal-multiplier circuit also receives a current signal of the six-pulse diode-bridge rectifier
(IRect-1 ) in order to generate a signal proportional to 1/3 of the
current IRect-1 . As a result, the reference current signal to be
imposed at the switched converters is obtained at the output of
the multiplier circuit.
Finally, the PWM reference generator circuit receives the signal from the multiplier circuit and, with a sawtooth waveform,
provides the PWM reference current signal that is compared
with the current through the input inductor of the switched converters. Therefore, the driving command to the main switched
converters’ switch is provided through the gate-drive circuit.
B. Experimental Results
After a careful simulation study using PSpice, two 6-kW
prototypes of the proposed PFC-HMPR were built and analyzed in a laboratory. The PFC-HMPR has been implemented,
deploying modified SEPIC converters and boost converters
fed through isolating transformers. The parameters set for the
prototypes are presented in Table I.
The harmonic content of the input-line currents and input
voltages, the input power factor, the displacement factor, the
true power, the reactive power, and the apparent power for each
phase are presented in Table II. These results were obtained
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Fig. 13. (a) Ch.1, dc link voltage (V0 ); Ch.2, current through the resistive load (I0 ); Ch.M, average output power of PFC-HMPR (P0 ). (b) Ch.1, rectified input
voltage of Rect-2 (VDC ); Ch.2, rectified input current of Rect-2 (IL ); Ch.M, average input power of Rect-2.
using the Tektronix Software Solutions: WSTRO & WSTROU
WaveStar Software for Oscilloscopes/Trial Version.
It is important to outline that, when operating as an ordinary
12-pulse rectifier, the THDI achieved was less than 14% in
both prototypes, as expected and demonstrated in Section II.
Moreover, the switched converters’ power contribution in both
prototypes was less than 20%. The first prototype built in a
laboratory is shown in Fig. 11(a) and (b), where one can observe
the modified SEPIC rectifiers in detail.
In order to illustrate the performance of the proposed PFCHMPR, the experimental results are presented in the following
figures.
In Fig. 12(a) shows the ac input current of the uncontrolled
six-pulse rectifier (Rect-1), and in Fig. 12(b) shows the ac input
current of the modified SEPIC converter connected to line A.
In Fig. 12(c), the input-line current ia(in) is shown together
with the line-to-neutral voltage va . It is important to emphasize
that the current ia(in) is the result of the combination of currents
ia1 and ia2 (ia(in) = ia1 + ia2 ).
The input-line currents ia(in) , ib(in) , and ic(in) are shown in
Fig. 12(d). These signals were acquired using a two-channel
oscilloscope, and all signals shown in Fig. 12(d) were acquired
with the trigger level set to channel 1 (voltage va ).
The average input power of the uncontrolled six-pulse rectifier is shown in Fig. 13(a), and the average load power is shown
in Fig. 13(b).
The frequency spectrum of the input-line currents is shown
in Fig. 14 and compared with the harmonic-content restrictions
imposed by IEC61000-3-4.
Analyzing the frequency spectrum of the input-line currents
shown in Fig. 14, one can observe that the significant harmonic
components are the 11th, 13th, 23th, and 25th, as expected.
The second prototype built in a laboratory is shown in
Fig. 15(a) and (b), where one can observe the boost converters
in detail.
It must be observed that the power rating of the lowfrequency single-phase isolating transformers available in a
laboratory is much higher than the power rating processed
by each boost converter and that, being so, the size of the
controlled rectifiers deploying boost converters can be extremely reduced with a specific transformer designed for this
application.
Fig. 14. Frequency spectrum of the PFC-HMPR input-line currents—
operating as a 12-pulse rectifier—deploying modified SEPIC converters.
(a) Line A. (b) Line B. (c) Line C.
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DE FREITAS et al.: EVALUATION OF A HYBRID MULTIPULSE RECTIFIER FOR UTILITY INTERFACE
3039
Fig. 15. (a) Prototype of the PFC-HMPR deploying boost converters. (b) Boost converters.
Fig. 16. Main experimental results of the PFC-HMPR—operating as a 12-pulse rectifier—deploying boost converters. (a) Input-line current of Rect-1/Phase A.
(b) Input-line current of Rect-2/Phase A. (c) Input-line current and line-to-neutral voltage of PFC-HMPR/Phase A. (d) Input-line currents of PFC-HMPR.
Fig. 17. (a) Ch.1, dc-link voltage (V0 ); Ch.2, current through the resistive load (I0 ); Ch.M, average output power of PFC-HMPR (P0 ). (b) Ch.1, rectified input
voltage of Rect-2 (VDC ); Ch.2, rectified input current of Rect-2 (IL ); Ch.M, average input power of Rect-2.
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3040
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 54, NO. 6, DECEMBER 2007
compared with the harmonic-content restrictions imposed by
IEC61000-3-4.
In Table II, a summary of the PFC-HMPR experimental
results is given.
VII. C ONCLUSION
This paper has shown the analysis, design, and evaluation of
a novel hybrid power rectifier capable of achieving a near-unity
power factor. The system consisted of single-phase switched
converters connected to every leg of an ordinary six-pulse
diode-bridge rectifier. Such structure allowed a programmable
input-line current.
The parallel converters’ power rating was a fraction of the
total output power and depended on the desirable total harmonic distortion of the input-line current (THDI ). To impose a
12-pulse standard, less than 20% of the rated output power
is processed by the switched converters. Thus, this proposed
structure is recommended for high-power installations.
The proposed structure provided a multipulse ac current without using phase-shifting transformers, interphase
transformers, current-balancing transformers, and harmonicblocking transformers, providing a simplified design and a
reduced cost.
In addition to the converter analysis, experimental results of
the two 6-kW systems were found to corroborate the proposed
concept, the mathematical analysis, and the control strategy.
R EFERENCES
Fig. 18. Frequency spectrum of the PFC-HMPR input-line currents—
operating as a 12-pulse rectifier—deploying boost converters. (a) Line A.
(b) Line B. (c) Line C.
The experimental results shown in Figs. 16–18 corroborate
the analyzed theoretical results.
Fig. 16(a) and (b) shows the input-line currents of the
six-pulse diode-bridge rectifier and the boost converter, respectively. These currents are responsible in performing the
12-pulse waveform in the input-line current. The experimental
input-line current is shown in Fig. 16(c) and (d), providing
conditions to obtain a low THDI value as expected.
The average input power of the uncontrolled six-pulse rectifier is shown in Fig. 17(a), and the average load power is shown
in Fig. 17(b).
The frequency spectrum of the PFC-HMPR input-line currents, deploying boost converters, is shown in Fig. 18 and
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Luiz Carlos Gomes de Freitas received the B.S.,
M.S., and Ph.D. degrees in electrical engineering from the Federal University of Uberlandia,
Uberlandia, Brazil, in 2001, 2003, and 2006,
respectively.
He is currently with the Industry Division, Federal Center of Technological Education of Goiás
(CEFET-GO/UnED-Jataí), Jataí, Brazil, where he
has been working to establish research and education activities in the industry application of power
electronic converters. His research interests include
high-frequency power conversion, active power-factor correction techniques,
multipulse rectifiers, and clean-power applications.
3041
Marcelo Godoy Simões (S’89–M’95–SM’98) received the B.Sc. and M.Sc. degrees from the University of São Paulo, Guaratinguetá, Brazil, in 1985
and 1990, respectively, and the Ph.D. degree from
The University of Tennessee, Knoxville, in 1995. In
1998, he received the D.Sc. degree (Livre-Docência)
from the University of São Paulo.
He was a Faculty Member with the University of
São Paulo from 1989 to 2000. Since 2000, he has
been with the Colorado School of Mines, Golden,
and has been working on the research of fuzzy logic
and neural networks applications to power electronics, drives, and machines
control. He was a Visiting Professor with the University of Technology
of Belfort-Montbéliard, Belfort, France. He published the first book in the
Portuguese language about fuzzy modeling. He published two pioneering
books, one with CRC Press on the application of induction generators for
renewable energy systems and the other with Wiley/IEEE on the integration
of alternative sources of energy.
Dr. Simões is a recipient of the National Science Foundation (NSF)–Faculty
Early Career Development (CAREER) Award. This is the NSF’s most prestigious award for new faculty members, recognizing activities of teacher
scholars who are considered most likely to become the academic leaders of the
21st century. He served IEEE in various capacities. Currently, he is the ViceChair for IEEE IAS Industry Automation and Control Committee and an
Associate Editor for the IEEE TRANSACTIONS ON POWER ELECTRONICS.
Carlos Alberto Canesin (S’87–M’97) received
the B.S. degree in electrical engineering from the
São Paulo State University (UNESP), Ilha Solteira,
Brazil, in 1984, and the M.S. and Ph.D. degrees in
electrical engineering from the Federal University of
Santa Catarina, Florianópolis, Brazil, in 1990 and
1996, respectively.
From June 1985 to early 1990, he was an Auxiliary Professor with the Department of Electrical
Engineering (DEE), Faculdade de Engenharia de Ilha
Solteira (FEIS), UNESP, and became an Assistant
Professor in September 1990. From December 1996 to December 1998, he
was an Assistant Ph.D. Professor with the DEE, FEIS, UNESP, where he
became an Associate Professor in December 1998 and is currently an Associate
Ph.D. Professor. He started the Power Electronics Laboratory, UNESP. He is a
Research Engineer with the National Council of Technological and Scientific
Development, Brazil, and the State of São Paulo Research Foundation, Brazil.
From January 2003 to December 2004, he was an Editor with The Brazilian
Journal of Power Electronics, edited by Brazilian Power Electronics Society
(SOBRAEP). From November 2004 to October 2006, he was the President
of SOBRAEP, where he is currently a permanent member of the Deliberative
Council. His interests include soft-switching techniques, dc-to-dc converters, switching-mode power supplies, solar/photovoltaic energy applications,
electronic fluorescent ballasts, active power-factor correction techniques, and
educational research in power electronics.
Dr. Canesin is an Associate Editor for the IEEE TRANSACTIONS ON POWER
ELECTRONICS.
Luiz Carlos de Freitas received the M.Sc. and
Ph.D. degrees from the Federal University of Santa
Catarina, Florianópolis, Brazil, in 1985 and 1992,
respectively.
He is currently a Professor with the Faculty
of Electrical Engineering, Federal University of
Uberlandia, Uberlandia, Brazil. He has authored a
variety of papers particularly in the areas of softswitching, dc–dc, dc–ac, and ac–dc converters, electronic fluorescent ballasts, and multipulse power
rectifier for clean-power systems. He has published
in PESC’92, APEC’93, PESC’93, and IEEE TRANSACTION ON POWER
ELECTRONICS (Jan. 1995), the evolution of a zero-voltage turn ON and turn OFF
commutation cell that has been largely applied in power electronics research.
Dr. de Freitas has been a member of the Power Electronic Research
Group–Grupo de Eletrônica de Potência (NUEP), Federal University of
Uberlandia, since 1991.
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