Modeling and simulation of a moving-coil linear generator

This paper presents the flux analysis of moving coil linear generator using finite element method (FEM). Two generators, 6 poles and 8 poles are used to analyse and compare the flux distribution for air gap. The EMF for both generators are also analyzed. These generators will be used for free piston linear engine. A moving permanent-magnet linear generator has drawbacks of thermal and impact force demagnetization, in addition to requiring complex control strategies. To overcome these limitations, one of the solutions is to have a moving-coil linear generator. This paper presents the flux analysis using finite element method (FEM) for a moving-coil linear generator. The flux varies with a peak-to-peak value of 0.006 Wb with the movement of a single-turn coil. Flux density in the air gap changes sinusoidally with the addition of a DC component. EMF generated in the single-turn coil has a range of ± 2 Volts for a 1-mm air gap and ±1.5 volts for a 2-mm air gap. The analysis is performed to consider replacing the moving permanent-magnet by a moving-coil for a linear generator whose prime-mover is a free-piston linear combustion engine.