Modelling of a Free-Piston Generator Based on Spark-Ignition Engine, Linear Electric Machine and Active Rectifier

The Free-Piston Linear Generator (FPLG) technology is meant to serve as a link between the period of fossil fuels and the next green power generation. It consists of a Free-Piston Internal Combustion Engine (ICE) mechanically coupled with a Linear Electric Machine (LEM). No constraints on the piston movement and the inherently variable Compression Ratio (CR) result in a low vibrations, low friction, low maintenance costs, multifuel and high efficiency ICE, with a significant reduction of fuel consumption and greenhouse-gas emissions. In this paper the modelling of this new electricity generation system is investigated. The models of a gasoline single-piston Spark Ignition (SI) Free-Piston ICE and of the electric conversion system based on a three-phase LEM and a Space Vector Pulse Width Modulation (SVPWM) controlled active rectifier are developed in the CFD open-source OpenFOAM and Matlab Simulink environments, respectively.