Coupling Vibration Analytical Model and Vibration Suppression of Linear Motor Driven Free Piston Stirling Cryocoolers

Abstract

Linear motors are widely utilized in free-piston Stirling cryocoolers (FPSCs) due to their high efficiency, high reliability, and low noise. The reciprocating motion of the compression piston and the expansion displacer in a FPSC will inevitably lead to the vibration output. Most researches only focused on the vibration of a single moving component, and few studies discussed about the coupling vibration of linear compressor and expander. In this paper, the vibration of a linear motor-driven Stirling cryocooler is studied through theoretical analysis and experiments. A passive absorber is designed to suppress the vibration output from the linear compressor and expander simultaneously. The dynamic model of the Stirling cryocooler system is established, and the network transfer function between the input voltage and the system displacement of the linear motor is derived. The influences of these linear motor parameters of thrust constant, resistance and inductance, and working condition of charged pressure, is investigated in detail, on the system's vibration output. The experimental results are presented to evaluate the validity of the proposed model.