A cost-efficient long stroke field modulated linear machine

In the last two decades, the permanent magnet linear machines (PMLM) which could directly realize linear movement without any additional transmission mechanisms converting the rotary motion into linear motion, are widely applied in various linear motion systems. Although PMLM shows the advantages of high efficiency, high positioning accuracy and good controllability, the relative low cost-efficiency of the PMLM is a big barrier for long stroke applications. Unlike the rotary electrical machine, the linear electrical machine shows a unique geometric feature in different stator and mover lengths. Normally, the minimum length of the stator equals the sum of the mover length and the stroke. As a consequence, both the moving-coil PMLM and the moving-magnet PMLM are not cost-efficient for long stroke applications due to the high cost of the long stator which may consume an extensive amount of permanent magnets (PM) or copper.