| 摘要 |
PURPOSE:To retain notch characteristic even in constant power operation characteristic region by limiting the slip frequency command to predetermined level value in response to the notch command. CONSTITUTION:A slip frequency limiting circuit 23 for limiting the slip frequency command to predetermined level value in response to the output of a notch command circuit 22 is provided at a device for controlling the output voltage and the frequency of the inverter 15 through a control circuit 14 in accordance with the outputs from voltage control amplifier 8 and adder 13, the voltage of the motor is maintained at constant level, the slip frequency is raised approximately proportionally to the primary frequency of the motor, and the slip frequency is limited to a predetermined level in response to the output of the notch command circuit for instructing the notch characteristic at the time of controlling the motor. Thus, the notch characteristic corresponding to the weak field characteristics of the conventional resistance controlled vehicle can be incorporated even in the constant power operation characteristic region. |
