| 摘要 |
A method of operating a neutral point clamped (NPC) three level converter is provided. The NPC converter includes at least two legs, each leg comprising first and second top switches (48, 50) connected in series at a first mid point (49). The converter further includes first and second bottom switches (56, 58) connected in series at a second mid point (57), and first and second middle switches (52, 54) connected in series at a third mid point (53) therebetween. The first top and second bottom switches (48, 58) are connected in series at a DC link (30) and the first and the second middle switches (52, 54) are connected between the first and the second mid points (49, 57). Each of the top, bottom and middle switches has an antiparallel diode thereacross. The method includes alternately switching the first and second top switches (48, 50) to ON state when first middle switch (52) is in ON state and second middle switch (54) is in OFF state. The method also includes alternately switching first and second bottom switches (56, 58) to ON state when first middle switch (52) is in OFF state and second middle switch (54) is in ON state. |
