Patent ID: 7242157

Claim:
A method for controlling a magnetic flux in a magnetic body; said magnetic body being positioned relative to a conductive winding in such a way that a change of said magnetic flux is associated with an induced voltage across said winding; said induced voltage being proportional to a rate of change of said magnetic flux; said winding conducting an electric current; said method comprising the control of a voltage device connected to said winding; said voltage device producing an adjustable output voltage that controls said induced voltage, thereby controlling said rate of change of said magnetic flux; said adjustable output voltage causing said induced voltage to have such waveform and magnitude so as to be approximately proportional to a preferred rate of change of said magnetic flux; an instantaneous magnitude of said induced voltage differing from an instantaneous magnitude of said adjustable output voltage because of voltage drops associated with said electric current flowing through loop impedances; said method utilizing a parameter related to said electric current and characteristics of said loop impedances to control said adjustable output voltage so as to compensate for said voltage drops, thereby optimizing said adjustable output voltage for optimal control of said magnetic flux; wherein the improvement is in the control of said voltage device, said voltage device comprising an electric power supply means for providing one or more d-c voltage outputs, and an electronic switch means for periodically connecting said one or more d-c voltage outputs in series with said winding, said adjustable output voltage thereby being a pulsed voltage; said method further controlling said electronic switch means so that an average value over time of said induced voltage is approximately proportional to said preferred rate of change of said magnetic flux, thereby effecting control of said magnetic flux; whereby an energy efficiency of said method is improved.