Design and Optimization of a Single-Phase Tubular Linear Oscillating Permanent Magnet Machine for Stirling Generator

Stirling generator is considered as the most promising solution for energy conversion on the plateau. In order to meet the requirement of the free-piston Stirling engine, a moving-magnet single-phase tubular linear oscillating permanent magnet machine (MM-STLOPM) for Stirling generators is introduced in this paper. Compared with traditional flat linear machines, the sealing process is more convenient and the net radial forces can be eliminated theoretically. On the basis of developed multi-objective particle swarm algorithm (MOPSO), the structure parameters evaluated and identified as highly sensitive through the sensitivity analysis are optimized to maximize rated power, maximize rated force, minimize total voltage harmonic distortion, and minimize total force harmonic distortion. However, the substantial radial force of the MM-STLOPM in the eccentric state poses significant challenges of testing. Therefore, a moving-coil candidate (MC-STLOPM) without eccentric forces is further designed and optimized. For the sake of convenience and cost savings, segmented parallel magnetization was employed for PM manufacturing. Static force and power generation tests in combination with the Stirling engine were conducted on the manufactured MC-STLOPM. The results indicate that segmented parallel magnetization has minimal impact on performance and validate the consistency between simulation and experimental results, confirming the effectiveness of the theoretical analysis.