| 摘要 |
PROBLEM TO BE SOLVED: To suppress output variation of an AC motor without increasing the electromagnetic noise of a step-up converter.SOLUTION: When performing rectangular wave voltage control of an AC motor, output torque T is controlled by changing the voltage phase &phgr;v. In a region where the voltage phase is large (&phgr;v=&thetas;2), variation of torque T for the change of DC voltage VH corresponding to the amplitude of a rectangular wave voltage is large, when compared with a region where the voltage phase is small (&phgr;v=&thetas;1). The AC motor is controlled so as to avoid the rectangular wave voltage control in a region where the voltage phase &phgr;v is larger than a limit phase line PLN indicated by a set of limit phases set for respective DC voltages VH. |
