Methods and apparatus for maximizing and stabilizing electric power derived from wind driven source

An apparatus for maximizing power output of an electrical generator which may be driven by a source of variable power and speed and connected to AC mains lines under control of a power management circuit;

• and including an AC generator connected to and driven by said source, said generator having a rotor and a stator and having output lines for being connected to said AC mains lines;
• a voltage-controllable AC exciter connected to and driven by the shaft of said AC generator;
• and
• a frequency-controllable differential frequency converter interposed between the rotor windings of said AC exciter and the rotor windings of said AC generator, the output frequency of said AC generator being proportional to the speed of said shaft plus the frequency of said frequency converter, which comprises:
• means connected to said AC mains lines and to said output lines for generating a first control signal (e.g. e.sub.1) tending to increase the power output delivered by said AC generator;
• means connected to the output of said AC generator for developing a second control signal (e.g. e.sub.2) proportional to the "real" power developed by said AC generator;
• means connected to said first and second control signal generating means for generating a first error signal (e.g. e.sub.3) proportional to the algebraic difference between said first and second control signals for input into said power management control circuit;
• means connected to the output of said AC generator for developing a second error signal (e.g. e.sub.4) proportional to the difference in frequency between said AC generator and an internal frequency reference, said frequency reference being preset to be equal to the operating frequency of the electrical utility, to which the AC generator is to be connected;
• means connected to said AC exciter responsive to said first and second error signals for changing the voltage induced in the rotor windings thereof;
• means for connecting the output of said AC generator to said electric utility;
• and
• means connected to said frequency-controllable differential frequency converter and responsive to said second error signal for shifting the frequency of said frequency converter thereby to maintain said second error signal at a low value.