Multipath fan control method and control system

The invention provides a multipath fan control method and control system; the method comprises the following steps: generating pwm signals of more than 2 paths and with different duty ratios; selecting the corresponding pwm signal for each path fan from the more than two paths of pwm signals according to the speed needed by each path fan, and outputting a speed control signal of each path pan according to the selected pwm signal; outputting the speed control signals of all fans to the corresponding fans. The control method and system can realize concentration control of multipath fans, thus reducing circuit complexity of multipath fans, and equipment can be uniformly managed.