Power converter for an electrically-compensated constant speed drive

Abstract

An electrically-compensated constant speed drive according to the present invention includes a speed summer having first and second input shafts and an output shaft at which constant speed motive power is developed wherein the first input shaft is coupled to a prime mover output shaft. A speed-compensating permanent magnet machine includes a motive power shaft coupled to the second input shaft of the speed summer and electrical power windings. A control permanent magnet machine includes a motive power shaft coupled to either of the first or output shafts of the speed summer and also includes electrical power windings. A power converter interconnects the power windings of the permanent magnet machines and comprises a first bi-directional AC/DC converter coupled to the electrical power windings of one of the permanent magnet machines, a second bi-directional AC/DC converter coupled to the electrical power windings of the other of the permanent magnet machines, a bi-directional DC/DC converter coupled between the AC/DC converters and a circuit for controlling the converters whereby the speed compensating permanent magnet machine develops compensating speed of a magnitude and direction sufficient to maintain the speed summer output shaft at the desired speed.