| 主权项 |
1. A ventilating system comprising:
an electric fan including
a fan motor having a drive shaft, anda fan impeller connected axially to said drive shaft of said fan motor and driven by said fan motor to rotate; and a control unit including
a storage module storing a lookup table, said lookup table including relationship information among a rotational speed of said drive shaft of said fan motor, an airflow volume produced by said electric fan and power to be supplied to said ventilating system,a power detection circuit configured to detect a power signal received by said ventilating system so as to generate a power detection signal that indicates current power supplied to said ventilating system, anda control circuit coupled to said fan motor, said storage module and said power detection circuit, said control circuit receiving the power detection signal from said power detection circuit, being configured to generate, based on an airflow input signal associated with a desired airflow volume and on the power detection signal and with reference to said lookup table, a motor control signal associated with a target rotational speed of said drive shaft, and outputting the motor control signal to said fan motor; wherein said fan motor drives said fan impeller in response to the motor control signal from said control circuit to rotate together with said drive shaft at the target rotational speed, so that said electric fan produces the desired airflow volume. |
