"Mini Air Cooling Fan" experts know that if we open the DC cooling fan motors, you can see the DC cooling fan uses a variable frequency motor, coil from the position where it can be identified. "Mini Air Cooling Fan" inverter motor control circuit board, control chip DSP function will set the drive devices in one, simplifying the circuit structure. Through the control chip can be programmed to change the motor speed. DC "Mini Air Cooling Fan" of a three-phase star connection variable frequency motor control circuit, three-phase AC power supply through an inverter circuit composed of MOS transistors sharing power to the three windings of the motor.