Preliminary Design of a Single-Phase Linear Generator for Free-Piston Engine Application

This article proposes a single-phase permanent magnet linear generator (PMLG) applied to a free piston engine (FPE) to produce electricity. It has an outer stator and an inner rotor (mover) that is driven by a motor with a linear frequency ranging from 10 to 50 Hz. The generator model has been simulated in 3-D using the Finite Element Method (FEM) through Ansoft Maxwell V16 (AM-V16) software to determine the magnetostatic properties. The MATLAB software is then utilized to obtain basic output parameters such as current, voltage, and power, using these parameters. The simulation and experimental results show that the voltage, current, and power differ insignificantly from 10 to 30 Hz. However, the difference is significant in the speed range from 40 to 50 Hz due to magnetic saturation. The peak power and efficiency are achieved at approximately 140 W and 81% with a load RL = 10 Ω at a linear frequency of 50 Hz. The results from this study show that single-phase linear generators are completely applicable to power generation on FPE.