Brushless high-frequency alternator and excitation method for DC, single-phase and multi-phase AC power-frequency generation

A brushless high-frequency alternator device for use in the generation of fixed power-frequency electrical power from an external source of rotary mechanical power into n desired power-frequency output line voltages, L1, L2 . . . Ln, wherein n is any positive integer greater than zero, and wherein each of the output line voltages has a power-frequency time-varying sinusoidal amplitude, and wherein the various output line voltages are phase displaced one from another as required, the device comprising:

• (a) a shaft;
• (b) a rotor coaxial to, and arranged to turn with, rotation of said shaft when coupled thereto;
• (c) a stator having an inner circumference and arranged coaxial to, and separated from, said rotor by a radial air gap;
• (d) a plurality of field coils located on said stator, said field coils arranged for excitation by electrical currents such that the inner circumference of said stator is divided into one or more sets of said integer n discrete circumferential sectors, each sector having a field modulated level of net magnetic excitation (mmf) therein, said mmf being substantially uniform across said sector, and said field coils further arranged so that the mmf in each of the said integer n sectors within each of the one or more sets corresponds to the instantaneous phase and amplitude of a corresponding one of the output line voltages L1, L2, . . . Ln;
• (e) a plurality of high-frequency windings for each of said sectors arranged so that rotation of said rotor generates multiple phases of high-frequency alternating electrical output which are amplitude modulated by the mmf within each of said sectors and also arranged so that the electrical output of each of the multiple high-frequency phases is phase displaced with respect to the electrical outputs of others of the multiple high-frequency phases so as to be suitable for rectification into an amplitude modulated rectified output corresponding in phase and amplitude to one of the output line voltages;
• and
• (f) means to couple said shaft to the external source of rotary mechanical power.