Design and analysis of magnetically-drive actuator applied for linear compressor

Abstract

A novel Magnetically Levitated Linear Actuator (MLLA), mainly consisting of a Halbach magnetized moving-magnet armature, a cylindrical frame, a rod and electromagnetic (EM) poles, is presented and analyzed for linear compressors applications. The Halbach magnetized armature naturally generates a periodically distributed magnetic field which is interacted with that induced by the EM poles. Therefore, an axially reciprocating thrust force is induced that is inherently suitable for high frequency drive for linear compressors. A lateral magnetic repulsive force, due to the eddy current induced at the cylindrical frame, to exert upon the rod is generated as long as the rod is deviated in the radial direction. Once the position of the rod is laterally deviated from the central position, the rod is automatically brought back by this magnetic repulsive force. The magnetic field distributions, axial thrust force and lateral magnetic repulsive force are numerically obtained by Governing Equations Analysis (GEA) under cylindrical coordinate. The Finite Element Method (FEM), by the commercial software ANSOFT Maxwell with Transient Solver, is employed to be compared with and validate the solutions obtained by GEA. It is shown that the GEA is extremely agreed with the results by FEM. At last, the efficacy of the proposed MLLA is examined and verified by intensive computer simulations and experiments.