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.