| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that for a multiple inverter, a plurality of single-phase two-level inverter cells are connected in series for each phase, but when this circuit is replaced with single-phase three-level inverter cells, the number of semiconductor elements increases and the device cost becomes expensive, although the number of control devices can be reduced.SOLUTION: To the output of a three-phase three-level inverter cell, for which two sets of a secondary windowing of an insulating transformer are inputted, is connected in series the output of a single-phase three-level inverter cell for which two sets of another secondary winding are inputted, the smoothing capacitor voltage values of the three-phase three-level inverter cell and single-phase three-level inverter cell are equalized, and the phase voltage amplitude of the three-phase three-level inverter cell is reduced to 1/2 of the phase voltage amplitude of the single-phase three-level inverter cell. Also, two forward converters of the three-phase three-level inverter cell are made to a first group, and each of three forward converters of the single-phase three-level inverter cell are made to be a second and a third group, then the converters are operated in phase within the group, and operated out of voltage phase between the groups. |
