This
paper highlights the power quality issues and explains the remedial measures
taken by means of hybrid front-end third harmonic current injection rectifiers.
Here zig-zag transformer is used as the current injection device so that the
advantages pertaining to the zig-zag transformer is effectively utilized. The
third harmonic current injection device along with three-level boost converter
at the output stage will increase the DC-link voltage. With less boost
inductance, generally half of the conventional boost converter inductance is
sufficient to implement the proposed converter structure resulting in reduced
ripple current and also the device rating is reduced by half of the output voltage.
Moreover, the power quality is well improved using third harmonic current
modulated front-end structure which is well appropriate for medium/higher power
applications. The experimental prototype of hybrid front-end converter is
developed in the laboratory to validate the MATLAB simulation results.
KEYWORDS
1.
Current
modulation circuit
2.
Front-end rectifier
3.
Power quality
4.
PFC
5.
Third harmonic
current injection
6.
Three-level
boost converter
7.
THD
8.
Zig-zag
transformer
SOFTWARE:
MATLAB/SIMULINK
CIRCUIT DIAGRAM:
Fig.
1. Schematic diagram of proposed front-end AC-DC converter
Fig.
2. Simulation results of input phase voltage, input phase current, input
voltage and current, DC-link voltage, and DC current for the proposed front-end
converter under load variations.
Fig. 3. Frequency spectrum of input line current ias at (a)
Light load condition
(20%) (b) Full load condition (100%).
Fig. 4. Comparison of power quality
indices with varying load of front-end AC-DC converter with six-pulse DBR (a)
Variation of THD of input current with load and (b) Variation of PF of input
current with load.
CONCLUSION
In
this paper, a front-end AC-DC converter employed with third harmonic current
injection circuit using a zig-zag transformer and three-level boost converter
has implemented for medium and high-power applications. The three-level boost
converter has realized with less boost inductance, an only half rating of the
conventional boost converter inductance thereby resulting in less ripple
current and also the device rating has reduced by half of the output voltage.
The third order current harmonic reduction has achieved by the zig-zag
transformer. With less magnetic rating, only 20% of the load rating is
sufficient to realize the zig-zag transformer. The proposed converter has
modeled, designed and its performance was analyzed by MATLAB simulation under
varying load conditions. An experimental setup has been developed, and the performance
of the system is verified from the hardware results. The proposed scheme
resulted in less input current and voltage THD and maintained PF close to
unity. Also, the other power quality parameters such as displacement PF and
distortion factor are well within the IEEE standards.
REFERENCES:
[1]
Abraham I. Pressman, “Switching Power Supply Design,” McGraw-Hill,
International Editions, New York, 1999.
[2]
B. Singh, B. N. Singh, A. Chandra, K. Al-Haddad, A. Pandey and D. P. Kothari,
"A review of single-phase improved power quality AC-DC converters," IEEE
Trans. on Ind. Electron., vol. 50, no. 5, pp. 962-981, Oct. 2003.
[3]
J. I. Itoh and I. Ashida, "A Novel Three-Phase PFC Rectifier Using a
Harmonic Current Injection Method," IEEE Trans. on Power Electron.,
vol. 23, no. 2, pp. 715-722, March 2008.
[4]
N. Vazquez, H. Rodriguez, C. Hernandez, E. Rodriguez and J. Arau,
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Efficiency," IEEE Trans. on Ind. Electron., vol. 56, no. 1, pp.
110-119, Jan. 2009.
[5] H. Y. Kanaan
and K. Al-Haddad, "Three-Phase Current-Injection Rectifiers: Competitive
Topologies for Power Factor Correction," IEEE Ind. Electron. Magazine,
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