電気学会論文誌●（●●●●●●●部門誌）
IEEJ Transactions on ●●●●●●●●●●●●●●●
Vol.●● No.● pp.●-●●
DOI: ●.●●/ieejeiss.●●.●

Paper

Two-step Commutation for Three-phase-to-single-phase
Matrix Converter with High-frequency Isolation
Shunsuke Takuma＊ Stundent member,

Jun-ichi Itoh＊a) Senior Member(Manuscript received Jan. 00, 20XX, revised May 00, 20XX)
This paper proposes a two-step commutation method for a three-phase-to-single-phase matrix converter. Conventional two-step
commutation cannot be applied at all operation regions because a commutation failure still owing to detection error of grid voltages.
In our proposed two-step commutation, we modulate only one of two devices in a bidirectional switch and utilize a zero vector tolet the switches naturally turn off, in this manner, the commutation failures are avoided completely regardless of the voltage
detection error. From experimental results, it is confirmed that the proposed two-step commutation undertakes safe operation to
avoid commutation failure. The input current total harmonic distortion at 10 kW with the proposed two-step commutation is
improved by 38% in comparison with the conventional four-step commutation.
Keywords: two-step commutation, current direction estimation, commutation failure.

1.

life time and a reliability of the switching devices are decreased by
the commutation failure which is based on the detection error.
In order to simplify the control hardware for the matrix converter,
two-step commutation methods have been proposed [5-11].
Commutation time in the two-step commutation is half of that in
the four-step commutation. This results in a short commutation timewith a simpler commutation algorithm. In particular, the two-step
commutation in [11] is achieved by zero vectors which is theswitching pattern of the additional circuit outputting the zerovoltage at the input terminal. Another two-step commutation in [610] uses both the voltage polarity and the current direction for thecommutation. However, the main problem of these conventional
two-step commutations is that either the additional circuit isrequired or the commutation failures still occur at the critical area
due to a detection error of the input voltage. A solution for thisproblem is that the commutation method is switched between theconventional two-step commutation and the four-step commutation.
However, this solution increases the number of switching step andrequires the implement of the two commutation methods.
The error between a reference and actual voltage occurs by thedead-time which is longer than the duration of each switching pulseof the matrix converter. In the low modulation index region, theinput current is distorted by the output voltage error due to theconventional several-step commutation. It is necessary to reduce
the number of the commutation step in order to reduce the output
voltage error.
In this paper, the two-step commutation is proposed for a threephase to single-phase matrix converter in order to improve the input
current total harmonics distortion (THD) in the low modulationindex region. The output voltage error is decreased by the proposed
two-step commutation due to less commutation. In addition, thecommutation failure does not occur regardless of the voltage
detection error. The original idea of this paper is to turning-on only
one of two devices in the bi-directional switches based on thecurrent direction and to use a voltage vector which let the switches
naturally turn-off. Therefore, the proposed two-step commutation is
unnecessary to switch between the conventional two-step

Introduction

A lot of studies on Electric vehicles (EVs) and Plug-in hybrid
vehicles (PHEVs) have been accelerated over the past decade.
Compared to the gasoline vehicle, EVs or PHEVs still faces one of
the main challenges, i.e. the long battery charging time. In order tosolve this problem, high-power low-profile battery chargers are
required [1-4]. In [5-9], isolated AC-DC converters using a matrix
converter as a medium frequency AC-AC converter connected withthe transformer at the primary side have been proposed. The volumeof the matrix converter is expected to be greatly reduced comparedto other topologies which employ a buffer capacitor because thebuffer capacitor in the high-power application such as the rapid
battery charger usually has to withstand a high current, which
increases the capacitor volume.
Generally, the matrix converters are required a commutation
sequence at the switching timing of the power devices to prevent a
commutation failure, i.e. short-circuit at a voltage source and opencircuit at inductive components. The conventional commutation
method is separated into two types, the voltage commutation
method based on the input voltage polarity and the current
commutation method based on the output current direction [10-13].
The voltage commutation works reliably when the relationship of
the input voltages is accurately obtained. These commutation
sequences are the four-step commutation which is divided into thefour steps to avoid the open-circuit and the short-circuit. Each stepis turned-on or turned-off a switch into the two bi-directionalswitches depended on the voltage polarity or the current direction.
The commutation time which is longer than the switching speed of
the switching devices is inserted among the first-step, the secondstep, the third-step and the fourth-step to prevent the commutation
failure. Therefore, the four-step commutation which is the voltage
commutation or the current commutation is a complex commutation
algorithm which greatly restricts the applicable control hardware. Aa) Correspondence to: Jun-ichi Itoh. E-mail:itoh@vos.nagaokaut.ac.jp＊
Nagaoka University of Technology. 1603-1,
Kamitomioka-machi, Nagaoka, Niigata, Japan 940-2188© 200● The Institute of Electrical Engineers of Japan.

1

Two-step commutation for Three-phase-to-single-phase Matrix Converter (Shunsuke Takuma et al.)Cs

Rs

Upper arm
Idc

Cin

Spt

Srp

Ssp

Stp

Snubber circuit
N=

imc

Srn

Ssn

Stn

Snr

Sns

Snt

Lout

Ll
N1

vmc

Input filter

N2
N1

Cout

N2

Load

vr
vs
vt

Lin

Spr

Sps

Middle-frequency
transformer

Diode rectifier Output filter

Lower arm
3f -1f Matrix converter
Fig. 1. Isolated AC-DC converter with three-phase-to-single-phase matrix converter.
commutation and another commutation method to prevent the
short-circuit at the critical area. The effectiveness of the proposed
two-step commutation is evaluated with a 10-kW prototype thought
experimental results.

2.

1
Vmax
Negative
Spl

or

Vmid

Circuit configuration and control method

Sml SmrFigure 1 shows the isolated AC-DC converter with the threephase to single-phase matrix converter. The proposed circuit
consists of a LC filter to eliminate switching ripple component of
the input current, a three-phase to single-phase matrix converterwith bi-directional switches, a medium frequency transformer, adiode rectifier, and a smoothing inductor in the output DC side. In
particular, the three-phase grid voltage is directly converted tomedium frequency single-phase voltage by the matrix converter.
Consequently, the volume of the transformer is significantly
minimized because this transformer is operated with this medium
frequency single-phase voltage

3.

Spr

Positive

2

3

1

4

Spl

Spl

Spr

Spr

Sml

Sml

Smr

Smr

Vmin
Snl

Vmax
Vmid

Snr

(a) Equivalent circuit

2

Vmax
Vmid

error

(b) Four-step(c) Conv. two-step

Fig. 2. Conventional commutation step. If the actual voltage
does not agree with the detection voltage, the short-circuit
occur by the commutation failure.
Initial state

First step

Vmax
Spl SprSpl SprVmid
Sml SmrVmid
Sml SmrVmin

3.1 Problem of conventional commutation method
Figure 2 shows the equivalent circuit at each arm of the matrix
converter. The equivalent circuit consists of the three voltage
sources (maximum-phase-voltage Vmax, middle phase-voltage Vmid,
minimum phase-voltage Vmin), current source which represents as
the current at the transformer, and three bi-directional switches.
Figure 2(b) and 2(c) show the transition situation from Vmax to Vmid
with the four-step voltage commutation and the conventional twostep commutation. If the actual voltage polarity does not agree withthe detection voltage polarity, the short-circuit via the grid occurs
in the commutation state of the four-step voltage commutation or in
the steady state of the conventional two-step commutation until
turning-on Smr.
3.2 Principle of two-step commutation
Figure 3 depicts
the principle of the proposed two-step commutation, which is
divided into three modes. Figure 3(a) shows the transition from thehigh voltage to the low-voltage. As shown in Fig. 3 (a), the switch
Spr turns-on at Vmax-phase when the matrix converter starts to transit
from Vmax-phase to Vmid-phase with the positive output current. At
first step, the switch Smr at Vmid-phase turns-on. Then, at second step,
the switch Spr turns-off and the current commutates from Vmax-phase
to Vmid-phase. The output voltage error occurs due to thecommutation from Vmax-phase to Vmid-phase. Figure 3(b) shows theVmax
Spl SprVmid

Two-step commutation method

Second step

Vmax

Sml Smr

Vmin

Vmin

Snl Snr

Snl Snr

Initial state(a) Vmax to Vmid
First step
Vmax

Vmax

Spl Spr

Vmid

Vmid
Sml SmrSml SmrSml Smr

Vmin

Vmin

Vmin

Snl Snr

Snl Snr

Initial state(b) Vmid to Vmax
First stepSpl Spriload
0Snl Snr

Second step

Vmax

Spl SprSpl SprZero Vmid

Vmid
Sml SmrSnl Snr

Vmax

Vmid

Vmin

Second step
Vmax

Spl SprSpl SprVmid

Vmax

Snl Snr

Sml SmrVmin

Sml SmrVmin

Snl Snr

Snl Snr(c) Vz to Vmax

Fig. 3. Proposed commutation sequence. The commutation
step is always two-step by proposed sequence.
transition from the low voltage to the high voltage. In contrast, theswitch Smr turns-on at Vmid-phase when the matrix converter starts

2

IEEJ Trans. ●●, Vol.●●, No.●, ●●●Two-step commutation for Three-phase-to-single-phase Matrix Converter (Shunsuke Takuma et al.)to transit from Vmid-phase to Vmax-phase with the positive output
current. At first step, the switch Spr at Vmax-phase turns-on and thecurrent commutates from Vmid-phase to Vmax-phase. Then, at second
step, the switch Smr turns-off. The output voltage error is zero when
the output voltage is changed from Vmax-phase to Vmid-phase. Figure3(c) shows the transition from zero-vector state to an input phase.
The output current decreases until zero in the initial state. After that,the output current keeps to zero because the current path is nothing
regardless of the switching state of Spr. Therefore, the zero-vector
state Vz is defined as an equivalent off state of all switching devicesof the matrix converter. The zero-vector state depend on the input
voltage polarity. At first step, the all switches turn-off because theoutput current is already zero. At second step, Spl turns-on and theoutput voltage is changed from zero to Vmax. Therefore, the output
voltage error should occur by the zero-vector. In this paper, thecommutation from the low to high voltage is excluded to achieve
the simple duty compensation because the output voltage error isalways a constant duty using other commutation.
In these commutation modes, the short-circuit and the opencircuit are avoided regardless of the voltage detection error by themodulation of only one of two devices in the bi-directional switches.
Therefore, the transition from an input phase to another input phasewithout any commutation failures is achieved. The initial state is on
state of Spl and then similar switching sequence are applied when
the output current direction is negative. The initial state of theequivalent commutation model for each arm is express by (1)S xl = 1
S xl = 0

S xr = 0
S xr = 1

iload  0
iload  0

x = p, m, nUpper arm

vmax-vmin
vmax-vmid

I dc
Nvmc

vmin
vmax

vmid vmin
vmax vmax

Actual value
Reference value

vmc

0-(vmax-vmid)-(vmax-vmin)
Error
imc

0

tl
t0

t1 t2

t3 t4 t5 t6 t7t8(a) Operation waveforms at high-frequency side
Spr

Sps

Spt

Srp

Ssp

Stp

Spr

Sps

Spt

Srp

Ssp

Stp

Vmax

Vmax

Vmid

Vmid

Vmin

Vmin

Srn

Ssn

Stn

Srn

Ssn

Stn

Snr

Sns

Snt

Snr

Sns

Snt

(b) t0- t1()where subscript x indicates p (Vmax-phase) or m (Vmid-phase) or n
(Vmin-phase) depend on the output line to line voltage Vpr. If theoutput voltage of the matrix converter is Vmax-Vmin, x of the upperside arm is p. In addition, x of the lower side arm is n.
Figure 4 shows the half-cycle operation of one switching period
including commutation in sector I. The relationship of phasevoltage is vr > vs > vt. The inductor current Idc is assumed to be ideal
as no ripple current.
(i) t0 - t1
Srp and Snt are on, whereas the output current direction is positive.
Therefore, Spr and Stn can only conduct the current through the diodeconnected anti-parallel with the switching devices.
(ii) t1 - t2
Ssp is turned-on. The current flow does not change because the Rphase voltage is higher than the S-phase voltage.
(iii) t2 – t3
Srp is turned-off. The output voltage is changed from Vmax-phase
to Vmid-phase. This matrix converter successfully outputs vector V2.
(iv) t3 – t4
Stp and Snr is turned-on, whereas the output current direction isstill positive.
(v) t4 – t5
Ssp and Snt is turned-off. The output voltage polarity is changed
to be opposite of the output current. Thus, the output current quickly
decreases to zero during tl. The time tl is expressed bytl = Llvmid vmin vmin vmax -

vmax
vmin

-

Lower arm(c) t1- t2

Spr

Sps

Spt

Spr

Sps

Spt

Srp

Ssp

Stp

Srp

Ssp

Stp

Vmax

Vmax

Vmid

Vmid

Vmin

Vmin

Srn

Ssn

Stn

Srn

Ssn

Stn

Snr

Sns

Snt

Snr

Sns

Snt

(d) t2- t3(e) t3- t4

Spr

Sps

Spt

Srp

Ssp

Stp

Spr

Sps

Spt

Srp

Ssp

Stp

Vmax

Vmax

Vmid

Vmid

Vmin

Vmin

Srn

Ssn

Stn

Srn

Ssn

Stn

Snr

Sns

Snt

Snr

Sns

Snt

(f) t4- t5(g) t5- t6

Spr

Sps

Spt

Srp

Ssp

Stp

Spr

Sps

Spt

Srp

Ssp

Stp

Vmax

Vmax

Vmid

Vmid

Vmin

Vmin

Srn

Ssn

Stn

Srn

Ssn

Stn

Snr

Sns

Snt

Snr

Sns

Snt

(h) t6- t7(i) t7- t8

Fig. 4. Transition situation during half cycle one
switching period.
where N is the turn ratio of the transformer, Ll is the leakage
inductance of the transformer, vmc is the single-phase output voltage,and Idc is the output current at dc side. The output voltage during tl
is the line to line voltage between Vmax -phase and Vmin -phase to()

3

IEEJ Trans. ●●, Vol.●●, No.●, ●●●Two-step commutation for Three-phase-to-single-phase Matrix Converter (Shunsuke Takuma et al.)minimize the time tl. This output voltage during tl is error. However,this output voltage error is ignored because this period is lower than
1/10 of a dead-time using the small leakage inductance and the highoutput voltage.
(vi) t5 – t6
The output current keeps to zero regardless of the switchingstates of Stp and Snr. The output voltage is also clamped to zero
because the inductor current at DC side is circulated at the dioderectifier in secondary side during zero-vector state. The
commutation failure occurs by next commutation sequences when
the output current is not zero. The time tl should be shorter thanzero-vector state from t4 to t6 to suppress the commutation failure.
(vii) t6 – t7
Stp and Snr can safely turned-off because the output current has
become zero when the time tl is shorter than zero-vector state.
(viii) t7 – t8
Srn and Spt are turned-on and the matrix converter outputs thenegative voltage.
In consequence, the proposed two-step commutation operates thematrix converter without any commutation failures regardless of thedetection voltage error at the input voltage.
Figure 5 shows the proposed two-step commutation sequence.
The output voltage error due to the dead time is considered. The
delay of one-step time occurs from the first step to the second step
as shown in Fig. 2 (a) when the matrix converter transits from an
input phase to another input phase in the positive output current. In
the transition from the zero-vector state to another input phase, allswitches have to be turned-off at the first step. Similarly, the delayof one-step time occurs from the first step to the second step asshown in Fig. 2 (b). Consequently, the compensation for the voltage
error due to the delay of one-step time of the proposed two-step
commutation is similar to that in the back-to-back converter, which
is significantly simpler than the output voltage error compensationin the four-step commutation.

4.

Commutation
state

110

V 2
V2 

1 V1
T2 =
A V1

v
v

101

000
Current
directionchange

010

011

001

M
Curernt(S ,S ,S )direction p m n
Positive 1 0 0
Negative 1 0 0(Spl,Spr,Sml,Smr,Snl,Snr)
1 0 0 0 0 0
0 1 0 0 0 0“1” ON“0” OFF

Fig. 5. Proposed two-step commutation sequence.
v

010
V
100 3

V2

II

010
001

i*

T2
III

I
T1

Vzero

001 V4100

V1 100v 001

VI

IV
V
001
V
010 5

V6

100
010

※ The number of ”1”means switch is Turn on
100 Srp’=ON, Ssp’=OFF, Stp’=OFF
001 Srn’=OFF, Ssn’=OFF, Stn’=ON

ExampleFig. 6. Space vector modulation.
Duty reference
T1+T2+Tz
T1+Tz
T2+Tz
Tz

4.1 Input current control for matrix converter Figure 6
shows the space vector modulation (SVM) applied to the threephase to single-phase matrix converter. The operation mode of
SVM is divided by every 60 deg. (Sector I, II, III, IV, V and VI) of
the input voltages. Output vectors which are close to the input
voltage vector are selected. In sector I, V 1 and V2 are used during
the first half of the control period as the positive voltage, whereas
V4 and V5 are used during the second half of the control period as
the negative voltage. Note that the zero vector Vz which outputs thezero voltage, is decided by the sector. These duty reference T1, T2,
and Tz are calculated by

1 v
A v

100

Steadystate

Circuit configuration and control method

T1 =Voltage error
Current
Positive Negative
direction
zero One-stepOne-step zero
One-stepP

CarrierSingle-phase
output voltage 0
Single-phase
output current 0
Positive

Current
direction(Estimation result)

Negative

Vz

V1

V2

Vz

V4

V5

Vz

Fig. 7. Estimation principle of current direction. The output
current is synchronized the switching carrier by SVM.
Therefore, the output current direction is also same
relationship.

()




TZ = 1 − (T1 + T2 )  A =

()

V1
V1

V2 
 ()
V2  
where v and v are − components of the input current reference,
v1, v1, v2, and v2 are also − components of the vectors V1 andV2 which are selected based on the area located the input current
4

IEEJ Trans. ●●, Vol.●●, No.●, ●●●Two-step commutation for Three-phase-to-single-phase Matrix Converter (Shunsuke Takuma et al.)Table I. Switching table for two-step commutation.

III
VI
I
II
IV
V
V1 V2 Vz V2 V3 Vz V3 V4 Vz V4 V5 Vz V5 V6 Vz V6 V1 Vz
100 010 001 010 010 001 010 001 100 001 001 100 001 100 010 100 100 010
Switching signal001 001 100 001 100 010 100 100 010 100 010 001 010 010 001 010 001 100
SectorVector

Sectoriu*,iv*,iw*
3i*,i*uvw⇒

Detection
value
vu, vv, vw
3

2

Space
vectormodulation

Vector

Switching patterngenerator
using Table I.

Zero vectorv, v
uvw⇒

2arctan

10Current
direction
estimation

Switchingsignals
6

Short-pulse
masking

6

Sortingby current

Current
directionGatesignals12

direction

Vz

Fig. 8. Signal generation for proposed two-step commutation.
reference.
4.2 Current direction estimation
Figure 7 shows thecurrent estimation method to achieve the proposed two-step
commutation. The current direction estimation is required for
reducing the current sensor which has the high current ratio and thewide bandwidth. The output current is synchronized with theswitching carrier by SVM. The switching signal for the zero vector
is selected to reduce the output current up to zero. In order toachieve the two-step commutation, the zero current timing at theoutput side is necessary until end of the zero vector. The output
voltage is clamped at the grid voltage during the zero vector when
the output current thought via grid voltage. After that, the output
current and voltage are also zero. The current direction estimationis achieved to keep the zero current at the output side until end of
the zero vector.
4.3 Implementation of proposed two-step commutation
Table I shows the switching table for the proposed two-step
commutation. The switching table depends on the sector and theselected output vector. The switching pulse of the same vector ischanged by the sector. According to the principle of the proposed
two-step commutation as shown in Fig. 3, the gate signals are
decided for the six bidirectional switches. For example, the output
vector V1 is selected in the sector I, Srp, Stp and Stn are turned-on. Ssp,
Srn and Ssn are turned-off.
Figure 8 shows the gate signal generation for the proposed twostep commutation which requires the complex commutation
algorism as the four-step commutation because the proposed twostep commutation only uses a switching table and the current
direction estimation. The one of two devices in the bi-directionalswitches is operated by the gate signals depending on the current
direction. Another one of that is turned-off during half cycle of theswitching frequency. Finally, the short-pulse in the gate signals ismasked because the short-pulse wide more than the sum of the raisetime and the turn-on delay time required between the switching andnext switching on the three-phase to single-phase matrix converter.

5.

Table II. Experimental condition.
Element

SymbolValue

Three-phase AC voltage

vac

200 V

Input frequency

f

50 Hz

Rated output power

Pout

10 kW

Carrier frequency

fc

Turn ratio of transformer

N1:N2

20 kHz1:2.4

Input filter
Output filter

350 H(2.3%)
11 F(4.7%)

Lout

1.3 mH

Cout

30 F

Snubber capacitor

Cs

30 F

Snubber resister

Rs
td

60 kW

Commutation time0

Lin (%Z)
Cin (%Y)

1.0 µsvu 250[V/div]0
iu 50[A/div]
220 A
irp 100[A/div]0

4[ms/div](a) Four-step commutation0

vu 250[V/div]0
iu 50[A/div]
irp 100[A/div]< 150 A

Experimental results0

Table II shows the experimental conditions for 10 kW. The
switching devices at the three-phase to single-phase matrix
converter uses IGBT (MITSUBISHI ELECTRIC: CM400C1Y24S). The one-step time td is decided by the switching
characteristics of IGBT. The sum of the raise time and the turn-on
delay time of this IGBT is shorter than 1.0 s. Therefore, the one-

4[ms/div](b) Two-step commutation

Fig. 9. Comparison of device current at matrix converter.
5

IEEJ Trans. ●●, Vol.●●, No.●, ●●●Two-step commutation for Three-phase-to-single-phase Matrix Converter (Shunsuke Takuma et al.)Input voltage vr 250[V/div]

Input voltage vr 250[V/div]

0

0

0

0
Input current ir 50[A/div]
Single-phase output voltage vmc 500[V/div]

Input current ir 50[A/div]
Single-phase output voltage vmc 500[V/div]

0

0

0

0
Single-phase output current imc 100A/div
Fig. 11(b)(a)

Current direction : Negative

Single-phase output current imc
100A/div

10[ms/div]

Input and output waveforms of matrix converter

10[s/div](b) Extended Fig 11(a)Fig. 10. Four-step voltage commutation with high modulation index (MI = 0.85) at rated power 10 kW.
Input voltage vr 250[V/div]

Input voltage vr 250[V/div]

0

0

0

0

Input current ir 50[A/div]
Single-phase output voltage vmc 500[V/div]

Input current ir 50[A/div]
Single-phase output voltage vmc 500[V/div]

0

0

0

0

Reach to zeroSingle-phase output current imc 100A/div

Single-phase output current imc 100A/div

Fig. 12(b)(a)

10[ms/div]

10[s/div]

Input and output waveforms of matrix converter(b) Extended Fig12 (a)Fig. 11. Proposed two-step voltage commutation with high modulation index (MI = 0.85) at rated power 10 kW.
step time sets to 1.0 s.
Figure 9 (a), (b) shows the experimental waveforms of the threephase to single-phase matrix converter at 10 kW with the four-step
commutation method based on the grid voltage polarity (voltage
commutation) and with the proposed two-step commutation method
respectively. The commutation failure applying the voltage
commutation occurs in the regions where the relationship of the gridvoltages changes. As a result, the surge current is approximately
220 A. Consequently, the life time and the reliability of theswitching devices is decreased. In addition, the input current isdistorted by the commutation failure. The proposed method basedon estimation of the output current direction achieves to avoid
short-circuit at the grid voltage. Consequently, the input current
distortion is low value by 2.9%. In addition, surge current is always
suppressed by the proposed two-step commutation.
Figure 10(a)-(b) show the experimental waveforms with the fourstep voltage commutation, and the extended waveforms at highmodulation index, respectively. The input current has low THD by
4.9% and high-power factor as 0.99. However, the output current
does not zero at zero vector.
Figure 11(a)-(b) show the experimental waveforms with theproposed two-step commutation, and the extended waveforms at
high modulation index, respectively. It is clear that the output

16.0

Input current THD[%]

14.0
12.0

Four-step voltage commutation

10.0

Two-step commutation

8.0
6.0
4.0

2.0

Modulation index 0.85

1p.u. = 10 kW

0.0
0.2

0.4

0.6
0.8
Input power [p.u.]

1.0

Fig. 12. Comparison of grid current THD at high modulationindex. The input current THDs of the proposed two-step
commutation and the conventional four-step commutation are
also same.
current at the zero vector state quickly decreases to zero. Therefore,
the surge voltage due to the output current does not occur when all
switches turn-off. It confirms from this result that the proposed two6

IEEJ Trans. ●●, Vol.●●, No.●, ●●●Two-step commutation for Three-phase-to-single-phase Matrix Converter (Shunsuke Takuma et al.)Input voltage vr 250[V/div]

Input voltage vr 250[V/div]
0

0

0

0
Input current ir 50[A/div]
Single-phase output voltage vmc 500[V/div]

Input current ir 50[A/div]
Single-phase output voltage vmc 500[V/div]
0

0

0

0

Reach to zeroSingle-phase output current imc 100A/div

Single-phase output current imc 100A/div(b)

10[s/div]

Fig. 14(b)10[ms/div]
Input and output waveforms of matrix converter(b) Extended Fig 14(a)Fig. 13. Four-step voltage commutation with high modulation index (MI = 0.30) at rated power 10 kW.
Input voltage vr 250[V/div]

Input voltage vr 250[V/div]

0

0

0

0
Input current ir 50[A/div]
Single-phase output voltage vmc 500[V/div]

Input current ir 50[A/div]
Single-phase output voltage vmc 500[V/div]

0

0

0

0
Reach to zeroSingle-phase output current imc 100A/div

Single-phase output current imc 100A/div
Fig. 15(b)(b)

10[ms/div]

10[s/div]

Input and output waveforms of matrix converter(b) Extended Fig 14(a)Fig. 14. Proposed two-step voltage commutation with high modulation index (MI = 0.30) at rated power 10 kW.
step commutation method operates the matrix converter without
any commutation failures regardless of the input voltage detection
error.
Figure 12 shows the characteristics of the input current THD witheach commutation method at the high modulation index. The input
current THD of the proposed two-step commutation is similar to
one of the conventional four-step commutation. The commutation
step is decreased by the proposed two-step commutation to keep the
performance of input current control.
Figure 13(a)-(b) show the experimental waveforms with theconventional four-step voltage commutation, and the extended
waveforms at low modulation index, respectively. The input current
is distorted by the masking of the short-pulse.
Figure 14(a)-(b) show the experimental waveforms with theproposed commutation, and the extended waveforms at low
modulation index, respectively. It confirms from this result that the
proposed two-step commutation method operates the matrix
converter regardless of the modulation index.
Figure 15 shows the distortion characteristics of each
commutation methods at the low modulation index. The input
current THD of the proposed two-step commutation is 7.7% at 10
kW. In the low modulation index, the proposed two-step
commutation has the high performance in comparison with the

16.0

Input current THD[%]

14.0

Four-step voltage commutation

12.0

37%

10.0

Two-step commutation

38%

8.0

6.0
4.0

2.0

Modulation index 0.3

1p.u. = 10 kW

0.0
0.2

0.4

0.6
0.8
Input power [p.u.]

1.0

Fig. 15. Comparison of grid current THD with each
commutation method at low modulation index. The input
current THD is improved by 37 % with the proposed twostep commutation in comparison with the conventional
four-step commutation.
conventional four-step commutation at entire loads.
Figure 16 shows the output voltage error of each commutation
method. The output voltage error is less than 0.4% regardless of the
7

IEEJ Trans. ●●, Vol.●●, No.●, ●●●Two-step commutation for Three-phase-to-single-phase Matrix Converter (Shunsuke Takuma et al.)modulation index. It is clear that the proposed two-step
commutation method is unnecessary to compensate the output
voltage error.
Figure 17 shows the distortion characteristics of each
commutation methods against the modulation index at rated 10 kW.
The input current THD of the proposed two-step commutation is
7.7% at 10 kW. The output voltage range is extended by 36% incase of same input current THD.
Figure 18 shows the efficiency characteristics of each
commutation methods. The efficiency characteristics with theconventional four-step voltage commutation and proposed two-step
commutation are almost same. It is clear that the switching loss ofthe matrix converter is not increased to improve the input current
THD by applying the proposed commutation.

6.

Output voltage error[%]

4.0

Four-step voltage commutation

3.0
2.0
1.0

Proposed two-step commutation0-1.0
Four-step current commutation

-2.0
-3.0
-4.0

0

fsw = 10 kHz, td = 1 s, 1p.u. = 0.866
0.4
0.6
0.8
1
Modulation ratio[p.u.]

0.2

Fig. 16. Comparison of output voltage error.

Conclusions
14.0

In this paper, the two-step commutation was proposed in thethree-phase to single-phase matrix converter. Compared to theconventional two-step commutation, the proposed two-step
commutation is always the safety operation regardless of thevoltage detection error. In addition, the commutation algorithm of
the proposed two-step commutation is much simpler than theconventional commutation. On the other words, the simple control
hardware is employed for the matrix converter with the proposed
two-step commutation. The input current THD with the proposed
two-step commutation is improved by 38% at the low modulationindex.

Input current THD[%]

12.0
10.0

38%

Four-step voltage commutation

8.0
6.0
4.0

Two-step commutation

2.0

Input power 1p.u.
0.0

References

0.1

(1)

M. Pahlevaninezhad, P. Das, J. Drobnik, P. K. Jain and A. Bakhshai, "A New
Control Approach Based on the Differential Flatness Theory for an AC/DC
Converter Used in Electric Vehicles," in IEEE Transactions on PowerElectronics, vol. 27, no. 4, pp. 2085-2103, April 2012.
(2) Kohei Aoyama, Naoki Motoi, Yukinori Tsuruta, and Atsuo Kawamura,”High
Efficiency Energy Conversion System for Decreaces in Electric Vehicle
Battery Terminal Voltage”,IEEJ Journal of Industry Applications, vol.5, no.1,
pp.12-19, 2016.
(3) S. Kim and F. S. Kang, "Multifunctional Onboard Battery Charger for Plugin Electric Vehicles," in IEEE Transactions on Industrial Electronics, vol. 62,
no. 6, pp. 3460-3472, June 2015.
(4) Fuka Ikeda, Toshihiko Tanaka, Hiroaki Yamada, and Masayuki
Okamoto,”Constant DC-Capacitor Voltage-Control-Based Harmonics
Compensation Algorithm of Smart Charger for Electric Vehicles in SinglePhase Three-Wire Distribution Feeders”,IEEJ J. Industry Applications, vol.5,
no.5, pp.405-406, 2016.
(5) R. Huang and S. K. Mazumder, "A Soft-Switching Scheme for an Isolated
DC/DC Converter With Pulsating DC Output for a Three-Phase HighFrequency-Link PWM Converter," in IEEE Transactions on PowerElectronics, vol. 24, no. 10, pp. 2276-2288, Oct. 2009.
(6) Mahmoud A. Sayed, Kazuma Suzuki, Takaharu Takeshita, Wataru
Kitagawa : ”PWM Switching Technique for Three-phase Bidirectional GridTie DC-AC-AC Converter with High-Frequency”, IEEE Transactions on
Power Electronics, 2016
(7) R. Garcia-Gil, J. M. Espi, E. J. Dede and E. Sanchis-Kilders, "A bidirectional
and isolated three-phase rectifier with soft-switching operation," in IEEE
Transactions on Industrial Electronics, vol. 52, no. 3, pp. 765-773, June 2005.
(8) M. A. Sayed; K. Suzuki; T. Takeshita; W. Kitagawa, "PWM Switching
Technique for Three-phase Bidirectional Grid-Tie DC-AC-AC Converterwith High-Frequency Isolation," in IEEE Transactions on Power Electronics,
vol.PP, no.99, pp.1-1(9) A. K. Singh; E. Jeyasankar; P. Das; S. Panda, "A Single-Stage Matrix Based
Isolated Three Phase AC-DC Converter with Novel Current Commutation,"in IEEE Transactions on Transportation Electrification, vol.PP, no.99, pp.1-1(10) A. Tajfar and S. K. Mazumder, "Sequence-Based Control of an Isolated
DC/AC Matrix Converter," in IEEE Transactions on Power Electronics, vol.
31, no. 2, pp. 1757-1773, Feb. 2016.
(11) Lixiang Wei, T. A. Lipo and Ho Chan, "Robust voltage commutation of the

0.3

0.5
0.7
Modulation index

0.9

Fig. 17. Comparison of grid current THD with each
commutation method at entire modulation index.

Efficiency[%]96

Proposed two-step commutation

92
Conventinal four-step commutation

88

84
1p.u. = 10 kW
80
0

0.2

0.4
0.6
Output power[p.u.]

0.8

1Fig. 18. Comparison of efficiency characteristic witheach commutation method.
conventional matrix converter," Power Electronics Specialist Conference,
2003. PESC '03. 2003 IEEE 34th Annual, 2003, pp. 717-722 vol.2.
(12) T. Schulte and G. Schröder, "Power loss comparison of different matrix
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pp. DS2c.9-1-DS2c.9-6.
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Lappeenranta, 2014, pp. 1-10.

8

IEEJ Trans. ●●, Vol.●●, No.●, ●●●Two-step commutation for Three-phase-to-single-phase Matrix Converter (Shunsuke Takuma et al.)Shunsuke Takuma(Student member) received his B.S. degree inscience of technology innovation from Nagaoka
University of Technology, Niigata, Japan in 2015.
Presently, he is a Ph.D. candidate at Nagaoka
University of Technology, Niigata, Japan. He is thestudent member of IEEJ and IEEE. His current
research interests include commutation techniques
and the implement of the matrix converter.

Jun-ichi Itoh

(Senior member) received his M.S. and Ph.D.
degree in electrical and electronic systems
engineering from Nagaoka University ofTechnology, Niigata, Japan in 1996, 2000,
respectively. From 1996 to 2004, he was with Fuji
Electric Corporate Research and Development Ltd.,Tokyo, Japan. He was with Nagaoka University ofTechnology, Niigata, Japan as an associate professor.
Since 2017, he has been a professor. His researchinterests are matrix converters, dc/dc converters, power factor correction
techniques, energy storage system and adjustable speed drive systems. He
received IEEJ Academic Promotion Award (IEEJ Technical Development
Award) in 2007. In addition, he also received Isao Takahashi PowerElectronics Award in IPEC-Sapporo 2010 from IEEJ, 58th OHM
Technology Award from The Foundation for Electrical Science andEngineering, November, 2011, Intelligent Cosmos Award from Intelligent
Cosmos Foundation for the Promotion of Science, May, 2012, and Third
prize award from Energy Conversion Congress and Exposition-Asia, June,
2013. Prizes for Science and Technology (Development Category) from theCommendation for Science and Technology by the Minister of Education,
Culture, Sports, Science and Technology, April 2017. He is a senior memberof the Institute of Electrical Engineers of Japan, the Society of Automotive
Engineers of Japan and the IEEE.

9

IEEJ Trans. ●●, Vol.●●, No.●, ●●●