Method for controlling rotational speed of motor of fan

Abstract

A method for controlling a rotational speed of a motor of a fan is provided in the present application, applicable to an air cleaner and including: calculating a suitable rotational speed range according to a space size of a use environment and a filter gauze type of the air cleaner; calculating a suitable rotational speed according to air quality sensed by a sensor or air quality information; subsequently, adjusting a rotational speed offset according to a relatively high or a relatively low rotational speed preferred by a user; checking whether a range at present is a timing enhancement range; determining that the rotational speed is not higher than a noise upper limit rotational speed; and setting a rotational speed of a motor of a fan.

What is claimed is: 
     
         1 . A method for controlling a rotational speed of a motor of a fan, applicable to an air cleaner and comprising the following steps:
 calculating a rotational speed range according to a space size of an environment and a filter gauze type;   calculating a rotational speed in the rotational speed range according to air quality sensed by a sensor or air quality information; and   adjusting the rotational speed according to a rotational speed offset.   
     
     
         2 . The method for controlling a rotational speed of a motor of a fan according to  claim 1 , further comprising: determining whether a range is a timing enhancement range to enhance the rotational speed. 
     
     
         3 . The method for controlling a rotational speed of a motor of a fan according to  claim 2 , further comprising: determining that noise generated by the rotational speed is not higher than a noise upper limit rotational speed, and setting a final rotational speed. 
     
     
         4 . The method for controlling a rotational speed of a motor of a fan according to  claim 3 , wherein the rotational speed range comprises a highest fan rotational speed and a lowest fan rotational speed, an area of the space is A square meters, a height of the space is H meters, a sundries rate in the space is p, air in the space is filtered by a maximum of T-max times per hour, the air in the space is filtered for a minimum of T-min times per hour, a quantity of air that can be cleaned by the filter gauze within each unit time is a clean air delivery rate (CADR), a fan rotational speed under the CADR condition is fan-CADR, and the highest fan rotational speed fan-max is:
   fan-max=fan-CADR× A×H ×(1− p )× T -max/CADR, and
   the lowest fan rotational speed fan-min is:
   fan-min=fan-CADR× A×H ×(1− p )× T -min/CADR.
 
   
     
     
         5 . The method for controlling a rotational speed of a motor of a fan according to  claim 3 , wherein values sensed by the sensor is divided into N ranges, the air quality falls in an n th  range in the N ranges, and the rotational speed fan-n is:
   fan- n =fan-min+(fan-max−fan-min)×( n− 1)/( N− 1).
   
     
     
         6 . The method for controlling a rotational speed of a motor of a fan according to  claim 3 , wherein a cleaner operates at a relatively high rotational speed fan-boost for m minutes when the enhancement range is at an interval of M minutes, and the rotational speed is:
   fan- n ′=max of((fan- n +fan-offset),fan-boost).
   
     
     
         7 . The method for controlling a rotational speed of a motor of a fan according to  claim 3 , wherein the noise generated by the rotational speed is determined not to be higher than the noise upper limit rotational speed fan-noise, and the final rotational speed fan-final is:
   fan-final=min of(fan- n ′,fan-noise).