| 摘要 |
PURPOSE:To reduce unpleasant sound by altering a generation period ratio of a voltage vector designated by a switching table to a zero vector to control to switch a predetermined repetition period, and allowing a primary current to follow up an instructed value. CONSTITUTION:A switching table 208 for assigning a voltage vector having a rotating direction component designated to draw a substantially circular trace corresponding to a phase angle theta at a primary crossing magnetic flux vector obtained by a designated primary frequency is provided, and outputs an output voltage vector command V1* directly to an inverter 209 from phase angle theta information of a primary crossing magnetic flux vector. In this case, the generation period ratio of the voltage vector designated by the switching table 208 to the zero vector is altered to be controlled by a predetermined repetition period to allow a primary current to follow up the designated value. Thus, unpleasant electromagnetic sound change generated by the switching of a carrier frequency at the time of accelerating/decelerating can be reduced. |
