| 摘要 |
PURPOSE:To reduce noise and vibration and enhance efficiency, by setting the carrier frequency of a PWM inverter device in a specified range. CONSTITUTION:The carrier frequency of the PWM inverter device for driving an induction motor for a ventilating fan is set to be 8-30kHz. To drive a three-phase induction motor 8, a three-phase PWM signal is inputted to each gate terminal of power MOSFETs 2-7, to set the power MOSFETs 2-7 into switching actions, and a DC power source 1 is chopped to generate a three-phase rectangular wave voltage. The noise and input electric power in the case of actually driving the motor while fixing the carrier frequency of the PWM inverter device 9 at 20kHz are compared with those in the conventional case of driving the motor while setting the carrier frequency to be about 1-3kHz. As shown in graphs, the present PWM inverter device 9 is superior to the conventional PWM inverter device in that noise is lower and efficiency is higher.
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