Optimization of Novel Voice Coil Motor Structure Designed for a Free-Piston Stirling Generator

In this paper, a novel voice coil motor (VCM) structure with two guidance permanent magnets (GPM) is proposed to cooperate with free-piston Stirling generator (FPSG). It is proved that the VCM has inherent advantages when coupling with the power piston of FPSG thanks to the reciprocating linear motion characteristics and the constant flux density feature. By deploying the GPMs, the problem of the flux density magnitude dropping at both end of the VCM is solved. Thus, the efficient stroke and the power density of FPSG is enhanced. Additionally, the magnetizing direction and size optimization of the GPMs is discussed by the finite element analysis.