A Double-Sided Complementary Vernier PM Linear Machine With High Magnet Utilization Factor Using Third-Order Harmonics

Double-sided PM linear machine (DS-PM-LM), which takes merits of high thrust density and low normal force, has great potential for direct-drive application. However, existing DS-PM-LMs still suffer from low PM utilization issue, which limits their wide application in practical cost-efficiency systems. In this article, an H-shaped double-sided Vernier PM linear machine (DS-VPM-LM) with complementary structure is proposed and a corresponding new winding configuration method utilizing magnetic gear effect is come up with. The novelty of this proposed linear machine is that an enhanced modulation effect utilizing flux densities modulated from the third-order harmonics in the air gaps and a double-sided distributed armature winding is designed to make full use of them with higher winding factor to boost the output thrust density of the linear machine. Meanwhile, the complementary structure is artfully constructed to provide a magnetic path for the working harmonics. Based on the finite element analysis, the proposed DS-VPM-LM with novel winding configuration could improve 32.89% higher thrust density, and 30.13% higher thrust density per PM volume under the fixed copper loss comparing with the machine with conventional concentrated winding. In addition, some design guidelines, such as slot/pole combinations and PM dimensions, are discussed. Finally, the performances of the proposed machine are evaluated by prototype experiments to verify the correctness of FEA simulation results.