Comparative Study of Transversal-Flux Permanent-Magnetic Linear Oscillatory Machines for Compressor

Traditional moving-magnet transversal-flux linear oscillatory machines (MTLOM) suffer from high fabrication difficulty and cost, low robustness and reliability, and low material utilization ratio, etc. In this paper, a novel stator-magnet moving-iron transversal-flux linear machine (SMTLOM) is proposed, with magnets inserted into the stator yoke (rather than mounted on stator poles) and mover composed of iron core only. First, the topology of proposed SMTLOM is described, as well as its operation principle. Then, the comparison rules are built to make fair comparison between the conventional MTLOM and the novel SMTLOM, from the perspective of practical application, including the same maximum size limitation, output thrust, and thermal source. By using a three-dimensional finite-element analysis (3-D FEA), comparisons of some key performance indexes, such as back electromotive force, thrust per coil length, thrust per magnets volume, thrust per machine volume, temperature distribution, material cost and structure reliability, etc., are made between these two types of machines. The results from 3-D FEA demonstrate that the novel SMTLOM has enjoyed merits of lower fabrication cost and weight, much higher reliability, thrust density, material utilization ratio, etc., which indicate that the novel SMTLOM is more suitable for driving compressor and easier for mass production.