Patent ID: 7288923

Claim:
A method of controlling an output voltage in a machine operable as an electric alternator/generator, the machine comprising a rotor and stator assembly, the assembly having a stator including at least a first winding, the assembly also having first and second magnetic circuits and a saturation control device, the first magnetic circuit including the rotor and encircling at least a first portion of the first winding, the second magnetic circuit encircling at least a second portion of the first winding remote from the first magnetic circuit, the first and second magnetic circuits coupled when current flows in the first winding, the second magnetic circuit including a portion which is selectively magnetically saturable, the saturation control device being operatively associated with the magnetically saturable portion of the second circuit and operable to controllably vary a saturation level of said saturable portion, the method comprising: reducing the saturation of the magnetically saturable portion as an output current of the machine reduces towards zero during a low or no-load condition; preventing an output voltage of the machine from rising above a threshold value during the low/no-load condition by allowing sufficient flux to leave the first magnetic circuit and circulate through the magnetically saturable portion when in an unsaturated condition to induce a reducing voltage in second portion of the first winding subtractive from the output voltage.