4-052

平成 31 年電気学会全国大会

Pure Sinusoidal Output Current-Source Inverter
Using Analog Linear Compensator
Eka Rakhman Priandana*

Toshihiko Noguchi

Graduate School of Science and Technology
Shizuoka University
Hamamatsu, Japaneka.rakhman.priandana.17@shizuoka.ac.jp

Graduate School of Science and Technology
Shizuoka University
Hamamatsu, Japan
noguchi.toshihiko@shizuoka.ac.jp

Abstract—A new hybrid multilevel current-source inverter(CSI) is proposed in this paper. The proposed CSI is composed ofa H-bridge, several DC current modules, and an analog linearcompensator. This compensator is utilized to superimpose alinear compensating current onto the staircase current waveformgenerated by the DC current modules in order to reform theoutput current to a pure sinusoidal waveform. As a result, an
output current with low harmonics can be delivered to the load
without using a large output filter. The efficiency of the proposedsystem can be over 80% according to computer simulations.

Iolinear
IoM-1
Io2

...
0~I/M

I/M

I/M
vo
io LoadKeywords—multilevel current-source inverter; superimposition;
staircase current; linear compensating current; harmonics;
efficiency; computer simulations

I.

QM-1

The goal for inverter development is to generate the puresinusoidal waveform with a low total harmonic distortion(THD) without any large output passive filters and without
sacrificing its efficiency. Methods to achieve this goal areeither using high-frequency pulse-width modulation (PWM)
techniques or employing multilevel techniques. However, eachtechnique has own disadvantages. The high frequency
switching techniques lead to high switching losses, meanwhile
the multilevel techniques bring high conduction losses.
Therefore, it is required to develop a power converter that cansolve the above all problems at the same time.
The authors [1] have reported a new concept of a hybrid
CSI by incorporating several DC current modules and a linear
current generator as described in Fig. 1. However, the actual
implementation of the proposed idea is still unclear from theviewpoint of the power source configuration. The system canbe improved if only a single power source is used.
This paper will clearly summarize the operation principle
and elaborate the implementation of the proposed design ofthe single-phase hybrid multilevel CSI. In the end of the paper,
some simulation results are presented on the basis of theirmeasured quantities.

2019/3/12～14

北海道

CoINTRODUCTION

In general, power converters are basically operated bymeans of a switching action to increase their conversion
efficiency. In order to reduce the harmonics caused by theswitching action, large output passive filters are always
needed and indispensable. On the other hand, linear amplifiers
such as class-A can generate a pure sinusoidal waveform butwith very poor power conversion efficiency.

QBQA
I/M

Q2

Q1

QC

QD

Fig. 1. Proposed concept of hybrid current-source inverter.

II.

CIRCUIT CONFIGURATION

Fig. 2 illustrates the operation principle of the proposedsystem. In order to realize this basic operation with a single
power source, the Fig. 1 is synthesized into a circuit depicted inFig. 3. As described in Fig. 2, the staircase current waveform isgenerated by the several DC current modules where each
module is represented by the circuit in Fig. 4. Then, a linear
current generated by the circuit in Fig. 5 is superimposed onto
this staircase current waveform and becomes a fully rectified
DC current waveform. In order to generate sinusoidal
waveform, a H-bridge is utilized to alternate the polarity of thecurrent whenever the zero-crossing of the reference is detected.
In order to control the current amplitude, the system senses
the output voltage and generates the maximum peak output
current, and this value becomes the reference after divided by
the number of levels. By applying this technique, the output
current will be constructed in the same number of levels
regardless of the load condition. In order to implement thistechnique, a controller circuit of the proposed system isdesigned as shown in Fig. 6.
The main drawback of linear current generator is low
efficiency. In order to minimize the power losses, the peakcurrent of the linear generator must be limited as low aspossible. As consequence, the current from each DC current
module is equally limited as well. Therefore, a high number oflevels is required for supplying the load with optimum power
conversion efficiency.

-83-©2019 IEE Japan4-052

平成 31 年電気学会全国大会

Fig. 2. Operation principle.
DC Current
Module-1

DC Current
Module-(M-1)

Linear DCCurrent
Generator

Im/M

Im/M

...

...

DC Current
Module-2

QB

QA

Fig. 7. 13-level hybrid multilevel CSI simulation result.

Im/M

vo
io Load0~Im/M

TABLE I.

SIMULATION RECORDED DATA.
13-level
20.0 A
100.3 V12.3 A
0.35 %
5.83 %
1.17 %
81.8 %

Co

Load current
Load voltage
DC current
THD-I after filtering
THD-I before filtering
THD-V
Efficiency

DC Source

QD

QC

Fig. 3. Proposed system.
ILLINIII.

D2Fig. 4. DC current module circuit.
R

R+R
RSENSE+VREF

RIo = VREF / RSENSEDC Source
Io

IV.

RLOAD

Fig. 5. Linear compensating current generator circuit.

PIC

1/M
IL2

Q1-2

PIC

Q1-3

PIC

1/M

...

2/M

Q2-2

1/M
IL(M-1)
1/M

√2

PIC

vo

Q2-3

(M-1)/M

M = (NLEVEL-1)/2
RMS

REFERENCES
[1]

3/M

PIC

VREF

Q2-1

1/M
IL3

Q1-(M-1)|ABS|

Q2-(M-1)

LinearGenerator

[2]

[3]

Fig. 6. Controller circuit of the proposed system.

2019/3/12～14

北海道

CONCLUSION

A new technique to generate a pure sinusoidal output
current using an analog linear compensator has been presented
with simulation results. By enlarging the number of levels, theefficiency of the proposed hybrid multilevel CSI can beimproved. In order to verify the simulations, the proposed
circuit is currently being investigated in several hardware
experimental setups.

...

Q1-1

QA
QB
QC
QD

AC 1 Vpp

IL1

SIMULATION TESTS

Computer simulations have been conducted to verify theproposed system. For comparison purpose, 13-, 17-, and 21level hybrid CSI configurations are tested. For simulation
parameters, the DC power source voltage is 200 V, inductor L
is 1 mH, the output capacitor CO is 6.8 µF, the load is 5 Ω/0.5
mH, and the output voltage is set to 100 V/60 Hz. Fig. 7
shows one of the simulation results, meanwhile the measured
quantities of the conducted simulations are listed in TABLE 1.
It is shown that the efficiency of the proposed system isimproved according to the number of levels. However, theTHD is increasing as well but still under 5 % tolerance.

Q2-21-level
20.1 A
100.8 V11.9 A
0.49 %
10.1 %
2.51 %
85.5 %

OUT
D3Q1

D1

Number of Levels
17-level
20.0 A
100.0 V11.9 A
0.43 %
8.07 %
1.57 %
83.7 %-84-

S. Yamaguchi, T. Noguchi, A. Ikegami, “Hybrid Current-Source
Inverter with High-Efficiency Characteristic and Low-Distortion
Output,” IEEJ Proceedings of Annual Conference, 2013, C4-2.
J. Lai and F. Z. Peng, “Multilevel converter-a new breed of power
converters,” IEEE Transactions on Industry Applications, vol. 32, no. 5,
1996, pp. 509-517.
Suroso and T. Noguchi, “New H-Bridge Multilevel Current-Source
PWM Inverter with Reduced Switching Device Count,” Proceeding ofIEEJ International Power Electronics Conference, 2010, pp. 1228-1235.

©2019 IEE Japan