| 摘要 |
<p>A PWM inverter apparatus controls the rotational speed of a motor (9) by setting the carrier frequency of a PWM-generated voltage at between 8 kHz to 16 kHz, to limit electric noise generated to within the non-audible range. A control circuit section (2) is provided with a triangular wave oscillator (11) which varies the frequency in accordance with a signal from a frequency setting section (1), so as to control the rotational speed of the motor (9) so that the level of electric noise generated can be reduced to a desirable value.</p> |
