Method for controlling cycloconverter circuit, cycloconverter circuit, and isolated converter

An isolated converter, comprising:

• a transformer;
• a control unit;
• and
• a cycloconverter circuit connected to a first side of the transformer, the cycloconverter circuit is configured to perform alternating current to alternating current conversion and comprises a plurality of switch elements connected in a plurality of current paths, wherein the plurality of switch elements are grouped into a plurality of groups, each of the plurality of groups comprising at least two switch elements disposed in each of the plurality of current paths, wherein the control unit is connected to the cycloconverter circuit and is configured to:
• when the cycloconverter circuit is in a zero-crossing detection stage, control the at least two switch elements in a first group among the plurality of groups to be turned on complementarily and the at least two switch elements in a second group among the plurality of groups to be turned on complementarily, wherein:
• during a dead time between drive signals for the at least two switch elements in the first group, a first target switch element among the at least two switch elements in the second group is turned on and remains turned on at least until an end of the dead time, the first target switch element being located in a same-direction current path as a switch element that is among the at least two switch elements in the first group and that is turned on after the dead time;
• during the zero-crossing detection stage, the drive signals for the at least two switch elements in the first group and drive signals for the at least two switch elements in the second group are each pulse signals, the drive signals for the at least two switch elements in the second group lead in phase relative to the drive signals for the at least two switch elements in the first group, and a phase lead amount of the drive signals for the at least two switch elements in the second group relative to the drive signals for the at least two switch elements in the first group is greater than or equal to the dead time between the drive signals for the at least two switch elements in the first group.