A method of using a cycloconverter switches a first switch of the first topology type to an on state after a magnitude of a current through an output inductor becomes less than a predetermined current threshold, and switches a second switch of the first topology type to an off state a first time after switching the first switch to the on state. Projections for supporting the holding cylinder at a predetermined position are provided on the outer surface of an axial portion which does not have the recess. A system control unit provides the control signals to the phase shifting unit.