A Permanent Magnet Linear Electric Machine for the Free-Piston Linear Generator System: Design and Experimental Verification

The free-piston linear generator can be employed as an auxiliary power unit in the hybrid electric vehicles due to the advantages of high efficiency and multi-fuel flexibility. This paper proposes a novel double-sided flat-type permanent magnet synchronous linear electric machine which is one of the key components of the free-piston linear generator. The flat-type mover is equipped with quasi-Halbach permanent magnet arrays on its double surfaces, and is sandwiched between two flat-type stators. Concentrated windings are inserted in the slots of the stators. The design considerations on the feasible slot and pole combinations are discussed. The major performance such as output power and efficiency are predicted via finite element method. A prototype is built up and the design has been verified through experiments. The results indicate that a high operation frequency can improve the output power, and efficiency can be optimized by regulating the loads.

[1]  J. F. Eastham,et al.  Novel synchronous machines: linear and disc , 1990 .

[2]  F. Rinderknecht,et al.  A highly efficient energy converter for a hybrid vehicle concept - focused on the linear generator of the next generation , 2013, 2013 Eighth International Conference and Exhibition on Ecological Vehicles and Renewable Energies (EVER).

[3]  Horst E. Friedrich,et al.  The Free Piston Linear Generator - Development of an Innovative, Compact, Highly Efficient Range Extender Module , 2013 .

[4]  R. Mikalsen,et al.  Recent commercial free-piston engine developments for automotive applications , 2015 .

[5]  I. Boldea,et al.  Permanent-magnet linear alternators part 1: Fundamental equations , 1987, IEEE Transactions on Aerospace and Electronic Systems.

[6]  R. Mikalsen,et al.  A review of free-piston engine history and applications , 2007 .

[7]  D. Howe,et al.  Tubular modular permanent-magnet machines equipped with quasi-Halbach magnetized magnets-part II: armature reaction and design optimization , 2005, IEEE Transactions on Magnetics.

[8]  D. Howe,et al.  Tubular modular permanent-magnet machines equipped with quasi-Halbach magnetized magnets-part I: magnetic field distribution, EMF, and thrust force , 2005, IEEE Transactions on Magnetics.

[9]  Fei Zhao,et al.  Hybrid System Modeling and Full Cycle Operation Analysis of a Two-Stroke Free-Piston Linear Generator , 2017 .

[10]  Fang Youtong.  Slot/Pole Number Combination Research of PM Linear Motors With Fractional Slots per Pole , 2012 .

[11]  Jingdong Chen,et al.  Development of a linear alternator-engine for hybrid electric vehicle applications , 1999 .

[12]  Zhen Huang,et al.  Flat-type permanent magnet linear alternator: A suitable device for a free piston linear alternator , 2009 .

[13]  Hidemasa Kosaka,et al.  Development of Free Piston Engine Linear Generator System Part3 -Novel Control Method of Linear Generator for to Improve Efficiency and Stability , 2016 .

[14]  Ocktaeck Lim,et al.  A review of free-piston linear engines , 2016 .

[15]  Frank Rinderknecht,et al.  Design of future concepts and variants of The Free Piston Linear Generator , 2014, 2014 Ninth International Conference on Ecological Vehicles and Renewable Energies (EVER).