Induction and synchronous linear motors are then evaluated for suitability to the application by analyzing their characteristics in this high-speed operating regime.

The study initially reviews the current state of high-speed electric machines in applications similar to the one proposed. This paper summarizes the results of a design study investigating the use of linear electric motors in an aerospace electromagnetic launcher application requiring 7g's of horizontal acceleration to a velocity of 300m/s. The crankshaft, which is normally required in conventional hybrid concepts, is therefore eliminated. This is the principle of the free-piston generator, producing electricity directly from the linear motion of the pistons. Now, if this rod is placed in a magnetic field (containing coils), and if the movement of the rod causes a disturbance of the field, an electromagnetic force (EMF) will be induced in the coils. The reciprocating, ignition and compression processes, in the two chambers cause the connecting rod to have an oscillating motion. The rod that connects the two oppositely placed combustion chambers also acts as a prime mover for the generator. An application of the free-piston generator in a series hybrid vehicle is also proposed. Some distinct electrical machine solutions are presented and discussed. Specifications for the electrical machine are outlined. These have implications upon the dimensioning and selection of an appropriate electrical machine.

Results from a simplified combustion modeling process are presented in terms of piston motion profiles. This paper presents the free-piston generator concepts, along with the expected benefits and drawbacks. This has benefits in efficiency, weight reduction, robustness, variable compression operation and multi-fuel possibilities. Thereby the intermediary crankshaft stage present in conventional hybrid topologies is eliminated. De Abstract-The free-piston generator is an energy conversion device that integrates a combustion engine and an electrical generator into a single unit.

The homopolar handbook