In accordance with an embodiment of the invention, there is provided a device for generating electrical energy using a thermal cycle of a working gas. The device comprises at least one piston movably mounted in a container to form a working chamber between the at least one piston and the container, the working chamber containing the working gas performing the thermal cycle. An electrical circuit is mounted stationary relative to the container, the electrical circuit being electromagnetically coupled to provide a motive force to the at least one piston. An electronic power converter is electrically connected to the electrical circuit and to an electrical bus, and an electrical storage device is electrically connected to the electrical bus. The at least one piston is movably mounted such that its motion electromagnetically induces current in the electrical circuit. An electronic controller is electronically connected to the electronic power converter to control motion of the at least one piston to perform, in the thermal cycle, at least one of: (i) expanding the working gas beyond the volume at which compression of the working gas is begun within the thermal cycle or (ii) exhausting the working gas to a remaining volume less than the smallest volume of compressed gas within the thermal cycle. The electronic controller further controls flow of electrical energy to and from the electrical bus to effect a net positive average power transfer from the working gas to the electrical bus over the course of the thermal cycle.