Single piston permanent magnet linear motor drive for a cryocooler-analysis and optimization

This paper presents the operation and analysis of a permanent magnet moving coil type fractional horsepower single piston linear electric motor, with a view to achieve optimization in terms of input current, copper losses and efficiency of operation. The basic equations governing the motion are written to obtain the intricate design details of the magnetic circuit. It is observed that there is wastage of around 40 to 45% of the flux available in the air gap. The theory of utilization of leakage flux is proposed, according to which it is required to optimize the coil length in order to utilize the leakage flux in the air gap. After the successful design and implementation of the single piston linear motor. The design of dual frequency linear motor is proposed, on the same lines, using axially energized magnets