| 摘要 |
PROBLEM TO BE SOLVED: To reduce cooling fan drive power by driving a cooling fan drive motor with a necessary minimum electric power. SOLUTION: In the drive control device, a target duty ratio d* for maintaining the temperature of an object to be cooled at an appropriate value is compared with a start duty ratio dS of PWM control for starting a motor by overcoming a static friction force of a cooling fan drive mechanism when starting a cooling fan drive motor. When the target duty ratio d* is the start duty ratio dS or larger, the motor is driven by PWM with the target duty ratio d* to start. When the target duty ratio d* is smaller than the start duty ratio dS, the motor is driven by PWM with the start duty ratio dS to be started. After the motor is started and preset start time is passed, a lower limit duty ratio dL (dL<dS) of the PWM control for driving the motor at the minimum rotation speed is compared with the target duty ratio d*. When the target duty ratio d* is the lower limit duty ratio dL or larger, the motor is driven by PWM with the target duty ratio d*. When the target duty ratio d* is smaller than the lower limit duty ratio dL or larger, the motor is driven by PWM with the lower limit duty ratio dL. COPYRIGHT: (C)2007,JPO&INPIT
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