Innovative linear compressor by magnetic drive and control

Abstract

A mathematical model for the magnetically levitated linear compressor (MLLC), which consists of a magnetic linear actuator, a pair of active magnetic bearings (AMBs), and a drive rod, has been developed. To prevent any potential wear or collision by the drive rod against conventional bearings, and certainly to reduce noise, the AMB pair is employed to regulate the lateral position deviation of the drive rod. The integral sliding mode control (ISMC) is synthesized to account for displacement-dependent system parameters and input non-linearities for the MLLC system. In addition, the closed-loop stability, under the presence of the reaction force by gas in the chamber, is proven by the Lyapunov direct method. Finally, the efficacy of the ISMC is verified by intensive computer simulations to ensure its superior regulation capability for lateral position deviation on the drive rod, retention of constant stroke of the piston, and counterbalance against the reaction force by gas during the Otto cycle.