Comparative analysis of 36, 48, 60 pulse AC-DC Controlled Multipulse Converter for Harmonic Mitigation

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1 Comparative analysis of 36, 48, 60 pulse AC-DC Controlled Multipulse Converter for Harmonic Mitigation Sonika Raghuvanshi 1, Nagendra Singh 2 Abstract: - This paper deals with Multi-pulse AC to DC conversion scheme for reduction of Total Harmonic Distortion. This conversion system employs a phase-shifting transformer and a three-phase. Every such converter provides 6-pulse AC to DC conversion, so in order to produce more sets of 6- pulse systems, a uniform phase-shift is required and hence with proper phase-shifting angle, 36, 48, 60 pulse systems have been produced. The performance enhancement of multi-pulse converter is achieved for total harmonics distortion (THD) in supply current, DC voltage ripples and form factor. All the simulations have been done on MATLAB platform for similar ratings for same configuration. The results are obtained for controlled converters for. Keywords:Multi-pulse, Total Harmonic Distortion, Form factor, Ripple Content 1. Introduction This paper a multi-pulse converter for high voltage & high power application for example as in HVDC. The technique shown is based on dc current reinjection. Moreover, a control strategy over the whole range of phase delay angle is obtained along with complicated input current and output voltage study. Due to power electronics device various harmonics are encountered and thus it subject to voltage dip [1, 7]. Devices such as adjustable speed drive, HVDC system, uninterruptible power supplies etc are employed with three phase ac-dc conversion. AC-DC converters also known as rectifiers, are developed by using thyristors and diodes which provides controlled and uncontrolled dc power[5,3]. The present work analyzes the different multi-pulse AC-DC converters in solving harmonic problem in the three phase system. It is also analyzed the performance of increasing the number of pulses on AC to DC converter [5, 6]. The performance enhancement of multi-pulse converter is achieved for total harmonics distortion (THD) in supply current, DC voltage ripples and form factor[6]. All the simulations have been carried out for similar ratings of R Load, for all the multi-pulse converters configurations, so as to represent a fair comparison among controlled continuations of multi-pulse converters [9]. The presented simulation results show the reduced THD at supply side. 2. Multi-Pulse Methods Multi-pulse methods involve multiple converters connected so that the harmonics generated by one converter are cancelled by harmonics produced by other converters [6]. By this means, certain harmonics related to number of converters are eliminated from the power source. In multi-pulse converters, reduction of AC input line current harmonics is important as regards to the impact the converter has on the power system[7-8]. For the simplicity & expediency these multipulse converter are shown in block of positive and negative group. The detailed of positive group is shown in each of the section below, in which only positive group is shown. 3. Simulation of Controlled Multi- Pulse Converters A. Thirty-Six Pulse Converter The connection for 36-pulse converter and the corresponding connections are shown in fig. 1,as a block diagram, and fig. 2 shows detailed positive group 3 six-pulse converters which are of positive phase sequence phase shifted by 10 0 from each other, can provide thirty-six pulse conversion, and obviously with much lower harmonics on AC and DC side. Its AC output voltage would have 30n±1order harmonics. Fig 1. Block diagram of 36 pulse converter. In figure above there are two blocks, upper block is showing the positive group and lower block is showing negative group. The detail analysis of positive group only is shown in figure 2, negative group is same as the positive group. Fig 2. Positive group of 36 pulse converter. ISSN: All Rights Reserved 2014 IJARCET 1159

2 B. Forty-Eight Pulse Converter In this configuration of 48 pulse operation, eight six-pulse converters phase shifted from each other by 7.5 degrees. All 8 transformer primaries are to be connected in series. Figure 3 shows the arrangement of 48 pulse controlled converter in which there are two groups positive and negative. Positive group contain 4 six pulse converter and similarly negative group contain another 4 six pulse converter. In figure 3 positive group 4 six pulse converter is shown. 4. Simulation Results obtained for Multi- Pulse Converters Controlled Multi-Pulse Converters (4.1) Analysis of Supply Current THD Table 1: Total Harmonic Distortion Observed on Simulation (4.2) Analysis of Ripple Content Fig 3. Controlled forty eight pulse converter (positive group) C. Sixty Pulse Converter In this configuration of 60 pulse operation, 10 six-pulse converters phase shifted from each other by 6 degrees. All 10 transformer primaries are to be connected in series. Figure 4 shows the arrangement of 60 pulse controlled converter in which there are two groups positive and negative. Positive group contain 5 six pulse converter and similarly negative group contain another 5 six pulse converter. In figure 4 positive group 5 six pulse converter is shown Table 2: % Ripple Content Observed on Simulation (4.3) Analysis of DC Voltage Form Factor Table 3: Form Factor Observed On Simulation The ripple content and the form factor blocks are shown below in figure 5. Fig 4. Controlled sixty pulse converter (positive group) Fig.5: Modeling for ripple content ISSN: All Rights Reserved 2014 IJARCET 1160

3 Pulse Converter Fig 6: Modeling for form factor 5. Out-Put of Simulation Results The figure in the following are given in three section ( ) first is source current (SC), second is Load current or output current (LC), third is D.C output voltage(ov) Pulse Converter Fig: 9 Output for SC, LC, OV for 60 pulse 6. Voltage /Firing angle output pulse Fig: 7 Output for SC, LC, OV for 36 pulse Pulse Converter Fig: 10 Output for voltage vs. firing angle for 36 pulse pulse Fig: 11 Output for voltage vs. firing angle for 48 pulse pulse Fig: 8 Output for SC, LC, OV for 48 pulse Fig: 12 Output for voltage vs. firing angle for 60 pulse ISSN: All Rights Reserved 2014 IJARCET 1161

4 7. Ripple/Firing angle outputs current THD decreases. The effect is similar for different multi-pulse converters pulse Fig: 13 Output for Ripple vs. firing angle for 36 pulse pulse Performance Analysis and Comparison All the data obtained after simulation of models using MATLAB/SIMULINK has been collected here so as to ease the comparison factors accounted for i.e. THD, Form Factor, Ripple Content. All the results obtained have been collected from Tables 4.1 to 4.3 and categorized on the basis of pulse provided so as to ease the comparison. Result of Simulation It is concluded therefore that in general with increase in number of pulses in multi-pulse case the performance parameters of these converters have remarkably improved. The THD for controlled converters has reduced than for the consecutive uncontrolled converters. The results are also compared and found effective with IEEE guide for Harmonic Control [2]. References [1] B. Singh, B. N. Singh, A. Chandra, K. Al-Haddad, A. Pandey, and D.P. Kothari, A review of three-phase improved power quality ac-dc converters, IEEE Trans. Ind. Electron., vol. 51, no. 3, pp , Jun Fig: 14 Output for Ripple vs. firing angle for 48 pulse pulse Fig: 15 Output for Ripple vs. firing angle for 60 pulse 10. Conclusion Simulation The various multi-pulse configurations were simulated using the software MATLAB/ SIMULINK [5] and the results have been presented in this chapter in Table 4 to Table 7. The effect of pulse variation on different multi-pulse converters reveals that with R load, there is smoothing effect on current and thus [2] IEEE Guide for Harmonic Control and Reactive Compensation of Static Power Converters, IEEE Std [3] A.Arvinda, A.Guha, Novel topology for 24 pulse rectifier with conventional transformer for phase shifting, Electrical Energy System (2011),IEEE Conference,pp ,2011. [4] R.Mayura, P.Agarwal, Performance investigation of Multipulse Converter for Low Voltage High Current applications,ieee Conference on Computer Science and Automation Engineering (CSAE),vol 1,pp , [5] D.A.Paice, Power Electronic Converter Harmonics- Multipulse Methods for Clean Power. New York, IEEE Press, [6] A.Chaturvedi, D. Masand- Comparative analysis of three phase AC-DC controlled multipulse converter: Electrical, Electronics and Computer Science (SCEECS), 2012 IEEE Students' Conference,pp 1-4,March 2012 [7] B.Singh, S.Gairola, B.N.Singh, A.Chandra, and K.A.Haddad, Multi-pulse AC-DC Converter for Improving Power Quality: A Review IEEE Transactions, On Power Delivery, Vol.23 No.1 January [8] G. T. Heydt, Electric Power Quality.West LaFayette, IN: Stars in a Circle Publication, ISSN: All Rights Reserved 2014 IJARCET 1162

5 [9] B. K. Bose, Recent advances in power electronics, IEEE Trans. Power Electron., vol. 7, no. 1, pp. 2 16, Jan [10] M. H. J. Bollen, Understanding Power Quality Problems: Voltage Sags and Interruptions. Piscataway, NJ: IEEE Press, [11] F. J. M. de Seixas and I. Barbi, A 12 kw three-phase low THD rectifier with high frequency isolation and regulated dc output, IEEE Trans.Power Electron., vol. 19, no. 2, pp , ar [12] R. Redl, P. Tenti, and J. D. Van Wyk, Power electronics polluting effects, IEEE Spectr., vol. 34, no. 5, pp , May [13] D. D. Shipp and W. S. Vilcheck, Power quality and line Considerations for variable speed ac drives, IEEE Trans. Ind. Appl., vol. 32, no. 2, pp , Mar./Apr [14] D. A. Jarc and R. G. Schieman, Power line considerations for vari- able frequency drives, IEEE Trans. Ind. Appl., vol. IA-21, no. 5, pp , Sep Nagendra.Singh born in Rewa, Madhya Pradesh, India. on June He has completed BE from Jawaharlal Institute of Technology, Khargone Madhya Pradesh in Electrical Engineering. He has completed his M.Tech in Power Electronic from NIIST, Bhopal India. Currently he is the research scholar in Electrical Engineering department from MewarUniversity, Chittorgarh, Rajasthan, India. His interest of area is power system, soft computing evolutionary techniques and power electronics. Mob [15] M. Rastogi, R. Naik, and N. Mohan, Optimization of a novel dc linkcurrent modulated interface with 3-phase utility systems to minimize line current harmonics, in Proc. IEEE Power Eng. Soc. Conf., 1992, pp [16] N.Mohan, T.M.Undeland, W.P.Robbins, Power Electronics: Converters, Applications, and Design, 3rd Edition, 2002 Bibliography 1. Ms. Sonika.Raghuvanshi born in Bhopal, Madhya Pradesh India on Aug 1985.She is completed her B.E from Radharaman Institute of Technology& Science in Electrical and Electronics Engineering, Bhopal (M.P).She is doing M-Tech in Power Electronics from the Department of Electrical and Electronics, Technocrat Institute of Technology,Bhopal.Her Research area of interest is power converter such as ac-dc-ac converters, power system and power electronic application in power. Mob ISSN: All Rights Reserved 2014 IJARCET 1163