A novel single-phase flux-switching permanent magnet linear generator used for free-piston Stirling engine

Abstract

This paper investigates a novel single-phase flux-switching permanent-magnet (PM) linear machine used for free-piston Stirling engines. The machine topology and operating principle are studied. A flux-switching PM linear machine is designed based on the quasi-sinusoidal speed characteristic of the resonant piston. Considering the performance of back electromotive force and thrust capability, some leading structural parameters, including the air gap length, the PM thickness, the ratio of the outer radius of mover to that of stator, the mover tooth width, the stator tooth width, etc., are optimized by finite element analysis. Compared with conventional three-phase moving-magnet linear machine, the proposed single-phase flux-switching topology shows advantages in less PM use, lighter mover, and higher volume power density.

Tubular unified magnetic‐field flux‐switching PMLM for free‐piston energy converter

“…The authors had developed a tubular single-stator flux-switching PMLM for FPEC, as shown in Fig. 1 [32]. In this paper, the authors try to introduce the above-mentioned dual-rotor and/or double-sided concepts into this machine topology, and realise a new machine topology which features unified magnetic field.…”

“…In this paper, the authors try to introduce the above-mentioned dual-rotor and/or double-sided concepts into this machine topology, and realise a new machine topology which features unified magnetic field. As a counterpart of the topology shown in [32], the proposed machine benefits from the dual-stator structure and integrated design of the magnetic circuit, so its mover yoke is removed, which is beneficial for improving the power density and reducing the mover mass. In comparison to the scheme in [32], the proposed machine is more suitable for the high-frequency oscillating motion condition.…”

The effect of power converter on the design of a Linear Alternator for use with a Joule Cycle-Free Piston Engine

“…Various linear machine topologies have been proposed as the electrical power take off in FPE applications, where high power densities, robustness and cost should all be taken into consideration. Permanent Magnet (PM) Flux Switching machines of single and three phase windings have been investigated for this application with their attractive construction [11,12], where the magnets are sandwiched between stator teeth structure. This linear machine topology is preferable for long stroke applications, where the long translator can be a purely iron structure.…”

Comparative study of tubular partitioned stator permanent magnet machines

“…Furthermore, the cost was reduced since only half the amount of PMs was used in this machine. As a good candidate for a free piston Stirling engine, a single phase tubular SFPM machine was introduced in [12]. The effect of the main design parameters on the machine performance was investigated.…”