Dual-stator Interior Permanent Magnet Vernier Machine Having Torque Density and Power Factor Improvement

Abstract

—An improved topology for a low-speed permanent magnet vernier machine, called a dual-stator interior permanent magnet vernier machine, is introduced to significantly increase torque density and power factor. A dual-stator is adopted in the design for more torque and improving space utilization. An interior spoke-type magnet array in the rotor is designed for magnet flux focusing, which can effectively increase useful flux and force flux lines to pass through the entire machine during operation as opposed to two separate torque components as in a normal dual-stator permanent magnet machine. To clearly place the advantages of the proposed topology in perspective, the proposed dual-stator interior permanent magnet vernier machine is compared to a well-known dual-stator surface-mounted permanent magnet vernier machine. This article discusses the operation principle and magnetic field analysis of the proposed machine and reports comparison simulation results taken from the finite-element method. In addition, the stator tooth is optimized for further better performance on torque density and power factor.

Keywords:

• AC machines
• dual stator
• finite-element method
• power factor
• permanent magnet vernier machine
• torque density

Additional information

Funding

This work was supported by the BK21PLUS program through the National Research Foundation of Korea funded by the Ministry of Education and by the Mid-career Researcher Program through the National Research Foundation of Korea grant funded by the Ministry of Science, ICT and Future Planning (NRF-2013R1A2A2A01068022).

Notes on contributors

Fei Zhao

Fei Zhao received her B.S. from Harbin Institute of Technology, Harbin, China, in 2010. She is currently a Ph.D. student in the Department of Electronic Systems Engineering at Hanyang University, Ansan, Korea. Her fields of interest are electric machine design, theoretical analysis, and structure optimization.

Thomas A. Lipo

Thomas A. Lipo was born in Milwaukee, WI, in 1938. He received his B.E.E. and M.S.E.E. from Marquette University, Milwaukee, in 1962 and 1964, respectively, and his Ph.D. in electrical engineering from the University of Wisconsin, Madison, in 1968. From 1969 to 1979, he was an electrical engineer with the Power Electronics Laboratory, Cooperate Research and Development, General Electric Company, Schenectady, NY. In 1979, he joined Purdue University, West Lafayette, IN, as a professor of electrical engineering. In 1981, he joined the Department of Electrical and Computer Engineering, University of Wisconsin, as a professor. He has been an Emeritus Professor since January 1, 2009. He has published over 550 technical papers, 5 books, and 40 patents and has received numerous awards for his work.

Byung-il Kwon

Byung-il Kwon was born in 1956. He received his B.S. and M.S. in electrical engineering from Hanyang University, Ansan, Korea, and his Ph.D. in electrical engineering from the University of Tokyo, Tokyo, Japan, in 1989. He was a visiting researcher with the Faculty of Science and Engineering Laboratory, University of Waseda, Tokyo, from 1989 to 2000; a researcher with the Toshiba System Laboratory in 1990; a senior researcher with the Institute of Machinery and Materials Magnetic Train Business in 1991; and a visiting professor with the University of Wisconsin–Madison, from 2001 to 2002. He is currently a professor at Hanyang University. His research interests are design and control of electric machines.