This technology was developed to address the limitations of traditional, single-fed linear alternators that require permanent magnets, adhesive bonding organics, and heavy iron laminations for flux control. They experience eddy-current losses and require electromagnetic interference protection. Furthermore, they have a limited operational temperature range (only up to 250 °C), which typically declines to below 200 °C as the adhesive bonding organics outgas and degrade over time. Consequently, they are limited to approximately 93% efficiency at ambient temperatures.
Glenn's linear alternator addresses all of the limitations of its predecessors and engenders a number of desirable new qualities — notably, the ability to reduce eddy-current losses by 25% and operate at 99% efficiency at temperatures up to 950 °C. It features a concentric, additively manufactured, monolithic copper plunger and stator. The stator is a stationary, single copper Halbach array, whereas the plunger is a moving, electromagnetic copper Halbach array.
A direct current is delivered through the conductive piston flexure support, which also provides reactive power for resonance. It creates a fixed magnetic field similar to that of a permanent magnet, but the magnetic field is channeled inward by the Halbach mover, doubling its strength.
By utilizing standard double-fed induction control methods, the reactive power can be transferred and adjusted between both coils. When used with the double-action, extremely light, thermo-acoustic (DELTA) converter, the engine/alternator system is one-tenth the weight of a traditional system. This innovative technology will enable a new class of vastly superior linear alternators with the ability to operate at extreme temperatures with increased performance and efficiency.