| 摘要 |
PROBLEM TO BE SOLVED: To stably perform the switching control of a positive-side converter and a negative-side converter without losing the vector of an actual current even when the sudden change of a load is brought about. SOLUTION: Vector control parts 17 to 22 control the torque component current Iqf and the magnetic flux component current Idf of AC currents I1u, I1v, I1w which are supplied to an AC motor 4 from converters 3a, 3b, 3c on the basis of a torque current standard Iq* and a magnetic flux current standard Id*, and when the polarity of the torque current standard Iq* is inverted, a torque current standard rate-of-change limiting means outputs a correction torque current standard Iqc* limited to a predetermined rate of change within a predetermined range including a zero. Therefore, even when a load is suddenly changed, the correction torque current standard Iqc* is not rapidly changed in the vicinity of a zero to suppress the rapid change of a current standard phase and to prevent all phase currents from becoming a zero, thereby stably performing the switching of the positive-side and the negative-side converters without losing a current vector. |
