Abstract--Power Quality is the major area of research interest amongst scientists. This is because of awareness created by IEEE 519-1992 like standards which implies the utility as well as consumers of electric power to improve the power quality. This paper investigates the potential of multi-pulse converter to be used as power quality solution. Six, twelve, eighteen and twenty four pulse converters have been modeled and simulated in Matlab environment. A Vast comparison is also presented among them. Index Terms-- Harmonics, High-Power Drives, Multi-pulse Converters, Power Quality. I. INTRODUCTION N present world, everybody talks about power quality. Power quality deteriorates due to the use of converters and other solid state devices to control the power flow. AC- DC-AC converters have been found their wide applications in industries such as steel rolling mills, paper mills, traction drives, FACTS devices etc. Such applications require high voltage & high current ratings. A lot of work has been reported in literature on the topologies and modulation strategies of AC-DC-AC converters. The main issues in designing these converters for specific applications are harmonic distortion (in output voltage and supply current), load power factor, efficiency, switching losses, real and reactive power control capability etc. A large series inductor is placed in the dc circuit to lower the ripple content of current which in turn helps to limit the harmonic distortion in the ac current. Advances in Power Electronics have made possible an efficient conversion from AC to DC or vice versa by the application of semiconductor switches. Conventional 2-level inverter with PWM technique is being used widely in various utility applications like harmonic filtering, reactive VAR compensation, voltage regulation, AC Drives, induction P. K. Chaturvedi, K. C. Pradhan and Veshali Goyal are with the Department of Electrical Engineering, Samrat Ashok Technological Institute, Vidisha (MP)- 464001 (India), Phone: 11-07592-(Res.)234505, (Off.)250297(123), Mobile-09826585016 (e-mail: pradyumnc74@rediffmail.com.) S. K. Jain is with the Department of Electrical Engineering, Maulana Azad National Institute of Technology, Bhopal, MP, India (e-mail: shailjain02@redifffmail.com) 0-7803-9525-5/06/$20.00 ©2006 IEEE. heating, standby power supplies and uninterruptible power supply etc. Harmonic reduction in compliance with IEEE standard 519-1992 [1] can be document provides an example of the desired layout for a PES technical work and can be obtained by these PWM techniques. Thanks to Pulse Width Modulation techniques for reducing the Switching Losses, dv/dt, total harmonic distortion, improving power factor, improving fundamental component of voltage and current output [3], [4]. Present research trend is towards improving the power quality of these converters. According to IEEE standard 519- 1992, harmonic contents should be less than 5%. So to met the IEEE 519 standard power quality is to be improved in terms of improved power factor, reduced total harmonic distortion (THD), reduced switching losses etc. These improvements can be achieved by selecting the appropriate modulation technique of various power devices in the converters. Power quality means the quality of power which we are receiving from utility. All the above mentioned performance indices are meant for power quality improvement. A better strategy for that will be to use muti- pulse converters. These types of converters are used in high- power (up to 200 MVA) Flexible AC Transmission Systems (FACTS) which are used to control power flow on transmission grids. It can also be used to build a model of shunt or series static compensator (STATCOM or SSSC) or, using two such converters, a combination of shunt and series devices known as Unified Power Flow Controller (UPFC) [5], [6], [7]. In this paper detailed modeling and simulation of multi- pulse converters is presented. Pulse-multiplication strategy has been presented including 6-pulse, 12-pulse, 18-pulse and 24-pulse converters characteristics both in the input current & in the output voltage. A comparison among these converters has been presented based on the output voltage and input current waveforms, total harmonic distortion in output voltage and input current, load power factor and switching losses. This scheme is an economic way to realize high performance HVDC conversion. With this scheme of pulse multiplication (for converters with more than 6-pulses output), THD in both input current & output voltage can be kept minimum over a wide range of phase delay angle. The overall performance of drive with multi-pulse converter is much better than that of six pulse converters. All the simulations have been carried out in Matlab- Simulink-Power System Blockset environment. Simulation study have been carried out by varying various circuit Multi-pulse Converters as A Viable Solution for Power Quality Improvement P. K. Chaturvedi, Shailendra Jain, K. C. Pradhan, and Veshali Goyal I