Analysis of 12 Pulse Phase Control AC/DC Converter

ABSTRACT:

 In this paper, the unbalanced current in the 12- pulse phase control AC/DC converters was studied. The 12- pulse A-Y type AClDC converter will keep a balanced voltage with 30″ phase shifted at the low coupling coefficient condition. But an unbalanced current will be obtained in the 12-pulse autotransformer phase shift AClDC converter at the low coupling coefficient condition. The theoretical phasor analysis of the unbalanced current was presented and a feedback controller was designed to overcome this problem. Finally, a 3 kW 12-pulse autotransformer phase shifted AClDC converter was implemented to demonstrate the theoretical analysis.

KEYWORDS:

  1. 12 Pulse AClDC Converter
  2. Phase Controller
  3. Autotransformer

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

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Fig. 1. Conventional 12-pulse AClDC converter.

(a) A-Y isolated transformer.

(b) Autotransformer phase shifted.

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Fig. 2. 12-pulse phase control A-Y connected AC/DC converter.

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Fig. 3. I;!-pulse phase control autotransformer connected AC/DC converter.

 EXPECTED SIMULATION RESULTS:

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Fig. 4 The output current io, and io, of 12-pulse phase control A-Y

typ: transformer ACDC converter with K=0.96 and a = 30″

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Fig 5 The output current io, and io, of 12-pulse autotransformer

phase shift ACDC converter with K=0.96 and a = 30″.

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Fig. 6 The output current of 12-pulse autotransformer connected

AC/DC converter with the controller

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Fig. 7 Experimental results for a resistive load without controller

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Fig. 8 Experimental results for a resistive load with controller

CONCLUSION:

 In this paper, the 12-pulse phase control ACDC converters with A-Y type and autotransformer type are analyzed and studied. The theoretical analysis is presented and the computer simulation results are performed. The 12- pulse A-Y type ACDC converter can function well under any firing condition. However, a serious unbalanced circulation current exists in the autotransformer connected ACDC converter at the non-unity coupling coefficient conditions. Finally, a 3 kW 12-pulse autotransformer phase controlled ACDC converter was implemented to demonstrate the theoretical analysis.

 REFERENCES:

 

  1. S. Choi, A. Jouanne, P. Enjeti and 1. Pitel, “New Polyphase Transformer Arrangements with Reduced kVA Capacities for Harmonic Current Reduction in Rectifier Type Utility Interface,“ IEEE PESC, 1995.

 

  1. S. Choi, P. N. Enjeti, H. Lee and I. J. Pitel, “A New Active Interphase Reactor for 12-Pulse Rectifiers Provides Clean Power Utility Interface,” IEEE IAS, pp.2468-2474, 1995.

 

  1. G. Oliver, G. E. April, E. Ngandui and C. Guimaraes, “Novel Transformer Connection to Improve Current Sharing on High Current DC Rectifier,” IEEE IAS, pp.986-962, 1993.

 

  1. S. Miyairi, etc.al, “New Method for Reducing Harmonic Involved in Input and Output of Rectifier with Interphase Transformer,” IEEE Trans. On Industry Applications, Vol. IA-22, No.5, pp.790- 797, SepIOct, 1986.

 

  1. A .R. Prasad, P. D. Ziogas, and S. Manias, “An Active Power Factor Correction Technique for Three-phase Diode Rectifier,” IEEE Trans. on Power Electronics, Vo1.6, No.1, pp.83-92, 1991

 

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