| 摘要 |
PROBLEM TO BE SOLVED: To restrict current without carrying out extra switching or without a load by reflux current concentrating on part of a semiconductive switching device. SOLUTION: When current is restricted in a reflux mode, it is determined which of an IGBT on the positive pole side or an IGBT on the negative pole side should be turned on between the first half and the last half of one cycle of a carrier signal Fc. In the first half when gate signals U to W of the IGBT on the positive side start under an on-condition, the gate signals U to W of the IGBT on the positive side are turned off, and the gate signals /U to /W of the IGBT on the negative side are turned on. In the last half when the gate signals U to W of the IGBT on the positive side start under an off-condition, the gate signals U to W of the IGBT on the positive side are turned on, and the gate signals /U to /W of the IGBT on the negative side are turned off. |
