Brushless high-frequency alternator and excitation method for three-phase ac power-frequency generation

An apparatus for generating three-phase electrical power output at a fixed power-frequency from the rotation of one or more external sources of variable speed rotary power, the apparatus comprising:

• (a) three field coils, each including power-frequency sinusoidal field currents excited at the fixed power-frequency, wherein there are three distinct phases of said power-frequency sinusoidal field currents, each phase displaced by one third of a power-frequency electrical cycle from the other phases, thereby creating three-phase power-frequency field currents;
• (b) three high-frequency alternator stages, wherein each of the high-frequency alternator stages is arranged to produce multiple phases of a high-frequency alternating electrical output from the rotation of the one or more external sources of variable speed rotary power when coupled thereto, and wherein the amplitude of said high-frequency electrical output of each of said stages is proportional to the amplitude of the sinusoidal field currents in said field coils;
• (c) three rectifiers, each one coupled to a corresponding one of the high-frequency alternator stages, wherein each rectifier rectifies said multiple phases of high-frequency alternating electrical output of the corresponding one of said high-frequency alternator stages into a distinct rectified high-frequency electrical output, and wherein the amplitude of each of the distinct rectified high-frequency electrical outputs is proportional to the level of the sinusoidal field currents in said field coils;
• (d) means for commutating each of said distinct rectified high-frequency electrical outputs, so that the polarity of each said distinct rectified high-frequency electrical output can be controlled;
• (e) means to regulate the commutation of each of said distinct rectified high-frequency electrical outputs as said output is modulated to zero, so that the polarity of each said distinct rectified high-frequency electrical output alternates every half cycle of the fixed power-frequency modulation to unfold each rectified high-frequency electrical output into a distinct power-frequency output with amplitude and phase corresponding to the amplitude and phase of a corresponding one said three phase power-frequency field currents;
• and
• (f) means to connect said three high-frequency alternator stages to the one or more external sources of variable speed rotary power.