A controller of a brushless DC electric machine having a rotor and at least a stator winding powered by a driving voltage is provided. The controller includes a position sensor, an advance angle control circuit, and a driving circuit. The position sensor is moved along a reverse rotating direction of the rotor by a prepositioned angle for outputting a position signal. The advance angle control circuit receives the position signal and a driving voltage reproduction signal reproduced from the driving voltage and outputs a commutation control signal lagging the position signal by a first delay time. The driving circuit receives the commutation control signal for outputting a driving signal for controlling a commutation of the brushless DC electric machine.