Patent ID: 6320356
Filing Date: 2001-11-20
Classification: H02M

Abstract:
A power unit comprising:a generator having three-phase output windings;a pair of variable control bridge circuits connected to said three-phase output windings of said generator and connected in an antiparallel manner to each other to form a cycloconverter for generating a single-phase alternating current to be supplied to a load;a bridge drive circuit for causing said variable control bridge circuits to be alternately switched to operate every half a repetition period of said single-phase alternating current, to thereby cause said cycloconverter to generate said single-phase alternating current;desired wave-forming means for forming a desired waveform of a drive signal input to said bridge drive circuit, for causing said drive bridge circuit to drive said variable control bridge circuits, such that said output single-phase alternating current has a desired alternating current waveform;waveform-changing means for changing a shape of said desired waveform in dependence on variation in said load so as to stabilize an output voltage of said cycloconverter; andamplitude-limiting means for limiting amplitude of said desired waveform to a smaller value when said output voltage of said cycloconverter becomes equal to or lower than a predetermined value.