| 摘要 |
PURPOSE: To control the r.p.m. of an induction motor, being used as a submersible motor, by means of an inverter. CONSTITUTION: The drive controller 1 for an induction motor comprises an inverter section 3 for controlling the r.p.m. of an induction motor through pulse width modulation, a filter section 4 for converting the output voltage from the inverter section 3 into a sine wave and outputting the sine wave, and a step-up transformer 5 for boosting the output voltage from the filter section 4. The step-up transformer 5 has a structure in which overexcitation phenomenon or biased magnetization does not take place. A voltage being applied from a drive power supply to the inverter section 3 is outputted in a rectangular waveform subjected to pulse width modulation. Output voltage from the inverter section 3 is converted through the filter section 4 into a sine wave from which higher harmonics are substantially removed. Output voltage from the filter section 4 is boosted without causing overexcitation phenomenon or anhysteretic phenomenon before being applied to the induction motor M. |
