IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 25, NO. 3, JULY 2010 1637 A Novel Three-Phase to Five-Phase Transformation Using a Special Transformer Connection Atif Iqbal, Member, IEEE, Shaikh Moinuddin, Member, IEEE, M. Rizwan Khan, Sk. Moin Ahmed, Student Member, IEEE, and Haithem Abu-Rub, Senior Member, IEEE Abstract—The first five-phase induction motor drive system was proposed in the late 1970s for adjustable speed drive applications. Since then, a considerable research effort has been in place to de- velop commercially feasible multiphase drive systems. Since the three-phase supply is available from the grid, there is a need to de- velop a static phase transformation system to obtain a multiphase supply from the available three-phase supply. Thus, this paper pro- poses a novel transformer connection scheme to convert the three- phase grid supply to a five-phase fixed voltage and fixed frequency supply. The proposed transformer connection outputs five phases and, thus, can be used in applications requiring a five-phase supply. Currently, the five-phase motor drive is a commercially viable so- lution. The five-phase transmission system can be investigated fur- ther as an efficient solution for bulk power transfer. The connection scheme is elaborated by using the simulation and experimental ap- proach to prove the viability of the implementation. The geometry of the fabricated transformer is elaborated in this paper. Index Terms—Five phase, multiphase, three phase, transformer, turn ratio. I. INTRODUCTION M ULTIPHASE (more than three phase) systems are the focus of research recently due to their inherent advan- tages compared to their three-phase counterparts. The applica- bility of multiphase systems is explored in electric power gen- eration [2]–[8], transmission [9]–[15], and utilization [16]–[33]. The research on six-phase transmission system was initiated due to the rising cost of right of way for transmission corridors, en- vironmental issues, and various stringent licensing laws. Six- phase transmission lines can provide the same power capacity with a lower phase-to-phase voltage and smaller, more compact towers compared to a standard double-circuit three-phase line. The geometry of the six-phase compact towers may also aid in the reduction of magnetic fields as well [12]. The research on multiphase generators has started recently and only a few ref- erences are available [2]–[8]. The present work on multiphase generation has investigated asymmetrical six-phase (two sets of Manuscript received September 09, 2009; revised January 01, 2010. Current version published June 23, 2010. This work was supported by AICTE, New Delhi, under Project 8023/BOR/RPS-86/2006–07. Paper no. TPWRD-00677- 2009. A. Iqbal, S. Moinuddin, M. R. Khan, and S. M. Ahmed are with the Depart- ment of Electrical Engineering, Aligarh Muslim University, Aligarh 202002, India (e-mail: rizwan_eed@rediffmail.com). H. Abu-Rub is with the Department of Electrical and Computer Engineering, Texas A&M University at Qatar, Doha, Qatar. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TPWRD.2010.2042307 Fig. 1. Block representation of the proposed system. stator windings with 30 phase displacement) induction gener- ator configuration as the solution for use in renewable energy generation. As far as multiphase motor drives are concerned, the first proposal was given by Ward and Harrer way back in 1969 [1] and since then, the research was slow and steady until the end of the last century. The research on multiphase drive sys- tems has gained momentum by the start of this century due to availability of cheap reliable semiconductor devices and digital signal processors. Detailed reviews on the state of the art in mul- tiphase drive research are available in [18]–[22]. It is to be em- phasized here that the multiphase motors are invariably supplied by ac/dc/ac converters. Thus, the focus of the research on the multiphase electric drive is limited to the modeling and control of the supply systems (i.e., the inverters [23]–[33]). Little effort is made to develop any static transformation system to change the phase number from three to -phase (where 3 and odd). The scenario has now changed with this paper, proposing a novel phase transformation system which converts an avail- able three-phase supply to an output five-phase supply. Multiphase, especially a 6-phase and 12-phase system is found to produce less ripple with a higher frequency of ripple in an ac–dc rectifier system. Thus, 6- and 12-phase trans- formers are designed to feed a multipulse rectifier system and the technology has matured. Recently, a 24-phase and 36-phase transformer system have been proposed for supplying a multipulse rectifier system [34]–[37]. The reason of choice for a 6-, 12-, or 24-phase system is that these numbers are multiples of three and designing this type of system is simple and straightforward. However, increasing the number of phases certainly enhances the complexity of the system. None of these designs are available for an odd number of phases, such as 5, 7, 11, etc., as far as the authors know. 0885-8977/$26.00 © 2010 IEEE