 Open Access
 Total Downloads : 1359
 Authors : Sneha.E.V.S, Sajin M
 Paper ID : IJERTV2IS110451
 Volume & Issue : Volume 02, Issue 11 (November 2013)
 Published (First Online): 14112013
 ISSN (Online) : 22780181
 Publisher Name : IJERT
 License: This work is licensed under a Creative Commons Attribution 4.0 International License
Design and Simulation of Single Phase Matrix Converter as a Universal Converter
Sneha.E.V.S Sajin M
PG Scholar PG Scholar
VIT University, Chennai, India VIT University, Chennai, India
Abstract
This paper represents a single phase matrix converter which is designed, simulated and analyzed as a universal converter where different power conversion topologies such as ACAC, DC DC & DC AC with regenerative capability are possible. The desired output for each converter topology was obtained using MatlabSimulink. Thus SPMC as a single converter capable of all sorts of power conversion is analyzed.

Introduction
Matrix converter is the most versatile converter which is basically an ACAC converter in which the frequency, amplitude and number of phases of the output voltage can be varied. The same circuit can also be used for DCAC, ACDC and DCDC conversions. It has several advantage including sinusoidal output voltage and input current, unity input power factor, inherent regenerative capability and absence of dc link which makes it suitable for different industrial applications. In this paper single phase matrix converter is analyzed for all possible modes of conversions including ACAC conversion, DCAC conversion with regenerative action, and DCDC conversion. SPMC is introduced by Zuckerberger in 1997. It has step up/down frequency transformation capability and the voltage will get stepped down. But for applications like traction rectifier, it is a desirable characteristic and the use of SPMC will reduce considerably the weight of the power transformer [1].
SPMC consists of two legs and four bidirectional switches. Since no monolithic bidirectional switches are available, two antiparallel IGBTDiode pairs can be used.
Fig 1 Single Phase Matrix Converter
The transfer function of the matrix converter is represented as T, input voltages Vin and Vout as the output voltage. The relation between input and output voltages of a matrix converter can be expressed as,
Vout = TÃ—Vin (1)
Number of methods is there in practice for the modulation of matrix converter. In this paper sinusoidal pulse width modulation (SPWM) is used. In SPWM sinusoidal reference signal is compared with triangular carrier and gating pulses are generated corresponding to the cross over points of both. Amplitude of the output voltage depends up on the ratio between the amplitudes of the reference signal and the carrier signal which is termed as modulation index and the output frequency can be varied by varying the frequency of the reference signal. By using higher switching frequencies, harmonics can be shifted to higher orders.

Analysis
Operation of SPMC in ACAC mode with variable output frequency, DCAC mode with regenerative capability and DCDC mode as a four quadrant chopper are analyzed.

SPMC as an ACAC converter with variable output frequency
Table 1 :ACAC Converter with variable frequency
Input Frequen cy
Output freque ncy
Mode
PWM
Switch
Commu tation Switch
50HZ
50HZ
1
S4
S1&S2
2
S1
S3&S4
100HZ
1
S4
S1&S2
2
S3
S1&S2
3
S2
S1&S2
4
S1
S3&S4
25HZ
1
S4
S1&S2
2
S2
S3&S4
3
S3
S1&S2
4
S1
S3&S4
When matrix converter is used as an ACAC converter where both input and output frequencies are 50HZ, it has two modes of operation. Mode 1 for positive half cycle of input voltage and mode 2 for negative half cycle. The switches used during each mode are given in the table above. When SPMC works as a cycloconverter with step up in frequency(50 to 100HZ) and with step down in frequency (50 to 25HZ), usage of switches for each mode is also given in the table. For 50 to 100HZ conversion, the switching pattern is so as to split the 50HZ waveform into four inorder that the frequency will result in 100HZ.

SPMC as DCAC Converter.
By simply varying the redundant switches, SPMC can work as a DCAC converter. Due to its inherent regenerative capabilities, SPMC inverter can serve as a rectifier by simply interchanging the positions of source and load with small changes in the switching combinations.
Conventional inverters and rectifiers cannot claim the capability of regeneration and on the other hand SPMC is maintaining a better RMS output voltage compared to them.
Table 2. SPMC as DCAC converter
Switching combination
Mode
Pwm switch
Commutation switch
Inverte r
1
S1
S4&S3
2
S2
S3&S4
Rectifie r
1
S4
S1&S2
2
S1
S3&S4

SPMC as DCDC Chopper.
Table 4. SPMC as DCDC chopper
itch
Switch position
First quadran t
Second quadrant
Third quadrant
Fourth quadran t
S1
pwm
open
open
open
S1
open
closed
open
open
S2
open
open
pwm
open
S2
open
open
open
closed
S3
open
pwm
close
open
S3
closed
open
open
closed
S4
closed
open
open
pwm
S4
open
closed
closed
closed
SPMC when works as a DCDC chopper will operate in all the four quadrants and the switch positions will be as shown in Table 3.


Simulation Results
SPMC working in the above mentioned modes are simulated using MatlabSimulink for the specifications given in table 4, and the obtained waveforms are given in Fig. 2 to Fig. 10. Table 5 gives the rms output voltages for the frequency changer mode of single phase matrix converter.
load
50 ohms
Input voltage
100V peak
Input frequency
50HZ
Output frequency
50HZ,100HZ,2
5HZ
Switching frequenc
5kHZ
Modulation index
0.8
load
50 ohms
Input voltage
100V peak
Input frequency
50HZ
Output frequency
50HZ,100HZ,2
5HZ
Switching frequency
5kHZ
Modulation index
0.8
Table 4. Simulation parameters.
(a)
(b)
Fig 2. gate pulses (a) with positive SPWM (b) negative
SPWM

SPMC as ACAC converter with variable output frequency
(a)
(b)
(c)
Fig 3. (a)Output voltage (b) Output current (c) Input voltage of SPMC in ACAC conversion mode for 50HZ
(a)
(b)
(c)
Fig 4. (a)Output voltage (b) Output current (c) Input voltage of SPMC in ACAC conversion mode for 50HZ to 100HZ.
(a)
(b)
(b)
Fig 5. (a)Output voltage (b) Output current (c) Input voltage of SPMC in ACAC conversion mode for 50HZ to 25HZ.
Table 5. Output voltage of SPMC working as frequency changer
Frequen cy
Rms output voltage
(volts)
5050HZ
68.62
50
100HZ
54.23
5025HZ
50.98

SPMC as DCAC converter with regenerative capability
Since SPMC has inherent regenerative capability by simply inter changing the source and load positions of an inverter it is possible to make it works as a rectifier. Changes have to be made only in the switching states as mentioned in Table 2. While comparing the performance of SPMC inverter and conventional inverter, it can be found that the RMS output voltage and THD of both are of comparable magnitudes, at the same time SPMC inverter has the advantage of regenerative capability due to the inherent bidirectional nature.
(a)
(b)
Fig 6. Output voltage of (a) Rectifier and (b) Inverter

SPMC as DCDC four quadrant choppert
(a)
(b)
(c)
Fig 7. (a) Output voltage (b) Output current and Input Voltage of First quadrant Chopper
(a)
(b)
Fig 8 . (a) Output voltage and (b) Output current waveforms of Second Quadrant Chopper
(a)
(b)
Fig 9. (a) Output Voltage and (b) Output Current waveforms of Third Quadrant Chopper.
(a)
(b)
Fig 10. (a) Output Voltage and (b) Output Current Waveforms of Fourth Quadrant Chopper.


Conclusion
It is observed that SPMC gives flexible and versatile conversion with all sorts of power conversion topologies explained in this paper, however similar to any other nonlinear power electronic circuitry the total harmonic distortion can be considerably high. But it can be reduced to substantially acceptable margin with the use of single stage filter, THD can be reduced below 4%[2]. Also it can also be observed that SPMC does not require a DC link. Therefore by using SPMC, it is possible to reduce the size of the converter and to improve its life time.

References

Venturini M, A New Sine Wave In Sine Wave Out Conversion Technique Eliminates Reactive Elements. Proceeding of Powercon 7,pp.E3/1E3/15.

Holmes D.G, and Lipo T.A, Implementation of a Controlled Rectifier Using ACAC Matrix Converter Theory, IEEE Power Electron. Sep. Conf. Rec.,1989,pp.353 359.