Monthly Archives: September 2016

Analysis of 12 Pulse Phase Control AC/DC Converter

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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

 

Operation of Series and Shunt Converters with 48-pulse Series Connected Three-level NPC Converter for UPFC

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ABSTRACT:

 The 48-pulse series connected 3-level Neutral Point Clamped (NPC) converter approach has been used in Unified Power Flow Controller (UPFC) application due to its near sinusoidal voltage quality. This paper investigates the control and operation of series and shunt converters with 48-pulse Voltage Source Converters (VSC) for UPFC application. A novel controller for series converter is designed based on the “angle control” of the 48-pulse voltage source converter. The complete simulation model of shunt and series converters for UPFC application is implemented in Matlab/Simulink. The practical real and reactive power operation boundary of UPFC in a 3-bus power system is specifically investigated. The performance of UPFC connected to the 500-kV grid with the proposed controller is evaluated. The simulation results validate the proposed control scheme under both steady state and dynamic operating conditions.

KEYWORDS:

  1. 48-pulse converter
  2. Neutral Point Clamped (NPC) converter
  3. Angle control
  4. Unified Power Flow Controller (UPFC)

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

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Fig.1 Schematic of Unified Power Flow Controller (UPFC)

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Fig. 2. 48-pulse VSC based +100 MVA UPFC in a 3-bus power system

EXPECTED SIMULATION RESULTS:

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 Fig.3 Line real power (top) and reactive power (bottom) references (MVA)

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Fig. 4 Measured real and reactive power, DC link voltage and converter angles (Top trace: measured line real power (MW); second top trace: measured line reactive power, (MVar ); third top trace: DC bus voltage; fourth top trace: shunt converter angle α ; fifth top trace: series converter angle α ; bottom trace: series converter angle σ ).

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Fig.5 Shunt converter output voltage (blue), Line voltage (green) and shunt converter current (red) (5.42s-5.48s)

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Fig.6 Shunt converter real power (blue, p.u.), reactive power (green, p.u.).

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Fig.7 Current (p.u.) of transmission line L1.

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Fig.8 Series converter 48 pulse converter voltage (blue, p.u.) and current (black, p.u.) during time 2~2.03s (when real power reference is increased)

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Fig.9 Series converter angle σ vs. DC bus voltage (Top trace: line real

power and reactive power; second top trace: shunt converter injected reactive

power; third top trace: DC bus voltage; bottom trace: series converter

angle σ )

CONCLUSION:

In this paper, the control and operation of series and shunt converters with 48-pulse series connected 3-level NPC converter for UPFC application are investigated. A new angle controller for 48-pulse series converter is proposed to control the series injection voltage, and therefore the real and reactive power flow on the compensated line. The practical UPFC real and reactive power operation boundary in a 3-bus system is investigated; this provides a benchmark to set the system P and Q references. The simulation of UPFC connected to the 500-kV grid verifies the proposed controller and the independent real power and reactive power control of UPFC with series connected transformer based 48-pulse converter.

REFERENCES:

[1] N. G. Hingorani, “Power electronics in electric utilities: role of power electronics in future power systems,” Proceedings of the IEEE, vol. 76, pp. 481, 1988.

[2] N. G. Hingorani and L. Gyugyi, Understanding FACTS: concepts and technology of flexible AC transmission systems: IEEE Press, 2000.

[3] L. Gyugyi, “Dynamic compensation of AC transmission lines by solid-state synchronous voltage sources,” IEEE Transactions on Power Delivery, vol. 9, pp. 904, 1994.

[4] C. D. Schauder, L. Gyugyi etc. “Operation of the unified power flow controller (UPFC) under practical constraints,” IEEE Transactions on Power Delivery, vol. 13, pp. 630-639, April 1998.

[5] L. Gyugyi. “Unified power-flow control concept for flexible AC transmission systems,” IEE Proceedings – Generation, Transmission and Distribution, vo. 139, pp. 323-331, July 1992.

Advanced Hybrid System for Solar Car

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Abstract

A three-input hybrid system for solar car is designed in this project. It consists of one unidirectional input power port and two bidirectional power ports with a storage element. Depending on utilization state of the battery, three different power operation modes are defined for the converter. Battery charging in the system is carried out from the amorphous solar panel mounted on the body and a solar energy harvesting charging station. Since the solar energy is directly given to the DC load, the efficiency of the system will improve. The capacitor which is connected to the lead acid battery will charge at off peak hours and discharge during the acceleration time of the car. In this proposed system energy wasted in the brakes are also recovered and used to charge the lead acid battery. Hence competent Hybrid Electric Vehicle was developed by using super capacitor and regenerative braking scheme.

 Keywords

  1. PhotovoItaic array
  2. Super capacitor
  3. Regenerative braking
  4. DC-DC Converter

 Software: MATLAB/SIMULINK

Block Diagram:

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Figure 1: When the vehicle is moving on a plane

 

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Figure 2: When the vehicle is ascending through the slope

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Figure 3: When the vehicle is descending through the slope

Expected Simulation Results:

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Figure 4: Output voltage of solar cell

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Figure 5: Output voltage of Boost converter

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Figure 6: Voltage across super capacitor

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Figure 7: armature current

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Figure 8: Speed of Armature

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Figure 9: input current to the motor

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Figure 10: Discharging current from the super capacitor

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Figure 11: speed of Armature

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Figure 12: generated current

 

Conclusion

At current levels of technology, installing a super capacitor with regenerative braking scheme provides a feasible method to improve the performances of the vehicles. The simulation results of the proposed systems show that the performance of the vehicle was improved in the following aspects.

(1) Provide better working conditions for the battery and increase its operating life.

(2) Source of energy extended up to the, regenerative braking scheme along with solar source, will increase the system reliability.

(3) Since the super capacitors have the ability to provide a large current in short time acceleration, performance of the vehicle will improve. Future scope of this work is to realize hardware model of the system.

References

[I] Bin Wu, Fang Zhuo, Fei Long, WeiweiGu, Yang Qing, YanQinLiu”A management strategy for solar panel battery -super capacitor hybrid energy system in solar car” 8th International Conference on Power Electronics – ECCE Asia May 30-June 3, 2011

[2] HyunjaeYoo; Seung-Ki SuI; Yongho Park; JongchanJeong; , “System Integration and Power-Flow Management for a Series Hybrid Electric Vehicle Using Super capacitors and Batteries,” Industry Applications, IEEE Transactions on , vo1.44, no.l, pp.I08-114, Jan.-Feb. 2008

[3] Jinrui N, Zhifu W’, Qinglian “Simulation and Analysis of Performance of a Pure Electric Vehicle with a Super-capacitor”2006 IEEE.

[4] T. Smith, 1. Mars, and G. Turner, “Using super capacitors to improve battery performance,” in Proc. IEEE Conf.PESC02, Jun., vol. 1, pp. 124-128.

[5] R. Schupbach, 1. C. Balda, “The role of Ultracapcitors in an Energy Storage Unit for Vehicle Power Management”, IEEE Proceedings of the 58th Vehicular Technology Conference, VTC 2003-Fall, Vol.3, 6-9 October 2003, Orlando,Florida.

Paper Writing and Paper Publication

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The scientific manuscript is a clear written document (Paper Writing) that illustrates a question and then gives a logical answer to this question based on theoretical or experimental or simulation results. A manuscript conveys the technical information to the reader, thus the presentation and discussion should be straightforward.

The origins and development of the scientific and technical press can be traced back to 1665 when the first “modern” scientific papers appeared and were characterized by non standardised form and style. Subsequently, nearly 300 years ago, in an attempt to ensure that articles met the journal’s standards of quality and scientific validity, the peer-reviewed process for scientific manuscripts was born in England and France. Since then, there has been an enormous proliferation of scientific journals and manuscripts so that, at present, the numbers of biomedical papers published annually by over 20,000 journals, at a rate of 5,500 new papers per day, far exceeds 2,000,000.

Published scientific papers and professional meetings are really essential to disseminate relevant information and research findings. However, most of the abstracts of presentations given at scientific meetings are usually available only in conference proceedings. Though they have the potential to be subsequently published as articles in peer-reviewed journals.

Possible reasons for failed publication include lack of time, research still underway, problems with co-authors and negative results. Undoubtedly, lack of the necessary skills and experience in the process of writing and publishing is another possible contributing factor. Also in the field of Transfusion Medicine although the specialists in this discipline are currently adopting the principles and research methodologies. High-level research is actually being carried out at the same rate as in all medical specialties.

There are three broad groups of manuscripts: original scientific articles, reviews and case reports.

We do write research papers and give guidance for publishing papers in good International Journals.

Paper writing

paper writing

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