Mike Carrell wrote:
An interesting idea. If you use expanding gases to drive a magentic piston
through some coils you will generate electricity with potentially good
efficiency. However the voltage and frequency will vary widely even from one
end of a stroke to another as energy is absorbed from the piston. Most
external systems expect standardized voltage and frequency. With modern
electronics it is possible to provide this.
The problem is similar to wind turbines. There is an optimum rotary speed
for coupling to various wind velocities, producing different genrator shaft
speeds.
Mike Carrell
The problem can be fixed with a rectifier and a few capacitors and
induction loops but there are looses. A simple rectifier and a
syncronous inverter can match a current to the existing grid current and
phase. In wind power one option is to drive the electro magnet with grid
power and synconise the switching so the field oscillated with the grid
and the induced current winds up in phase and at a steady voltage.
The bigger loss with this linear motor design is that part of the
combustion energy is wasted slowing, stopping and reversing the
direction of the piston. There is also the possibility that thermal or
mechanical shock could demagnetize the magnet.
