摘要 |
A method of controlling current of a multi-phase inverter is based on the principle that, when an appropriate switching mode is set, the direction of change of the position of the end of the current deviation vector must converge within a specific range which is determined in accordance with a presently output voltage vector. Accordingly, the direction of change of the position of the end of the current deviation vector and a presently set switching mode are detected during each control period to make a judgement as to whether or not the detected current deviation change direction belongs to a predetermined reference change direction range. When the answer of this judgement is affirmative, the presently set switching mode is found to be appropriate; therefore, this switching mode is maintained, whereas, when the answer of the judgement is negative, the switching mode is changed to a switching mode which has a reference change direction range to which the detected current deviation change direction belongs and which is determined in accordance with the presently output voltage vector. Thus, an appropriate switching mode is continued or newly set, and a voltage vector is selected from among voltage vectors which are allowed to be selected in this set switching mode, said voltage vector being capable of converging the current deviations within a predetermined range including the origin on the complex plane, and the selected voltage vector is employed as a voltage vector for the next control period.
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