| 摘要 |
PURPOSE:To suppress the variation in the torque of an induction motor by inserting a band pass filter to a detector which produces a feedback voltage, thereby feeding back a fundamental frequency component. CONSTITUTION:A DC voltage obtained through a pantograph 2 from a trolley line 1 is converted into 3-phase AC voltages via an inverter 3 and energizes an induction motor 4 to drive wheels 5, thereby traveling an electric motor vehicle. A filter 14 is inserted between an inverter voltage detector 13 which produces a feedback voltage and a rectifying and smoothing circuit 12. The filter 14 passes only the fundamental wave component from the output voltage waveform of the detector 13, and employs a band pass filter. The fundamental wave component of the output voltage of the inverter 3 becomes proportional to the frequency, thereby suppressing the variation in the torque of the motor. |
