| 摘要 |
PURPOSE:To suppress loss, magnetic noise, and distortion of current waves by alternating the zero vector, between the first vector where the switching elements on the upper side of each phase are turned on at the same time and the second zero vector where the switching elements on the lower side of each phase are turned on at the same time, with every pi/3 electrical angle. CONSTITUTION:The zero vector is alternated with every pi/3 in electrical angle between the first zero vector where the three switching elements Tra-Trc on the upper side of each phase are turned on at the same time and the second vector where the three switching elements Tra'-Trc' on the lower side of each phase are turned on at the same time. Accordingly, in case that arm short preventive time is provided during the ON time of the upper and lower switching elements Tra-Trc and Tra'-Trc', even if error voltages occur, the error voltages can be made so that the polarities and the shapes may be utterly reverse to each other at the positions where phases are different by 180 deg., and even harmonics and superfluous junior harmonics can be suppressed. |
