"Tiny Cooling Fan" chip digital control signal based on the rotor position sensor, according to the control signal (forward or reverse, etc.) required to calculate the magnetic field direction, and control of the power drive unit driving the stator windings, the electromagnetic field generated by the rotor magnet to phase suction or repulsion, driving the rotor spin. "Tiny Cooling Fan" rotor rotation, digital control chip at any time based on the signal of the rotor position sensor is calculated so that the rotor continues to rotate the magnetic field direction needed to control the power drive unit driving the stator windings to change the direction of the electromagnetic field, continue to drive the rotor to rotate. "Tiny Cooling Fan" continuous work throughout the process, so always keep an electromagnetic field in the forward rotation of the rotor position and role in maintaining optimal angle between the rotor magnets.