| 摘要 |
PURPOSE:To prevent sound, generated from a motor, from being heard as noise by a method wherein a carrier frequency control means, controlling a carrier frequency so as to be changed in accordance with a predetermined musical interval changing pattern, is provided. CONSTITUTION:An inverter main circuit 1 is controlled through PWM control based on a carrier frequency and operating frequency to drive a motor 2. The carrier frequency is controlled by a carrier frequency control means 3. In this case, the carrier frequency control means 3 controls the carrier frequency so that the operating sound of the motor 2 becomes a pattern showing the change of a predetermined musical interval. In this case, the changing pattern of the musical interval is a pattern capable of obtaining some melody. Accordingly, when the inverter main circuit 1 is controlled through PWM control based on the controlled carrier frequency to drive the motor 2, the operating sound, generated from the motor 2, appears as the change of some musical interval and becomes a melody in this case. |
