Dc/ac conversion circuit and control method therefor, and modulation method for cycloconverter

A DC/AC conversion circuit, comprising an inverter unit, at least one cycloconverter, and a controller,

• wherein the inverter unit is configured for converting a direct current into an alternating current;
• the at least one cycloconverter is connected to the inverter unit, the at least one cycloconverter comprises a plurality of sets of switching elements, the plurality of sets of switching elements are connected to an output port of the inverter unit respectively and configured for performing AC-to-AC conversion, and an output port of the at least one cycloconverter is configured to connect to a power grid and provide an alternating current output, wherein each of the plurality of sets of switching elements comprises at least two switching elements which are connected in reverse;
• and
• the controller is connected to the inverter unit and the at least one cycloconverter and is configured for controlling, when a grid voltage is within a threshold range, corresponding two of the plurality of sets of switching elements to complementarily turn on, wherein the threshold range comprises a zero crossing.