FAN MOTOR CONTROLLER AND FAN MOTOR CONTROL METHOD

摘要

Generation of strange sound is suppressed while protecting a power element and the operable area of a fan motor is restrained from becoming narrower by controlling repetition of interruption and reset of a signal delivered to the fan motor. When overcurrent of a brushless DC motor is detected, a fan motor controller interrupts a signal delivered to the brushless DC motor. Subsequently, a modulation factor maximum limit value is set such that the modulation factor is limited to satisfy a condition that the modulation factor of a signal delivered to the brushless DC motor falls within a range of the modulation factor when an overcurrent is detected (S52, S53). When the modulation factor maximum limit value is less than a preset lower limit value (S54: No), that lower limit value is set as the modulation factor maximum limit value (S55).