Brushless motor controller drives the speed have a variety of ways. Below small make up take you to understand it. 1. Duty ratio control: it is according to the change of the equivalent output voltage, so that the speed change motor controller. 2. Torque control: is according to the size of the change of output current, so that the output torque of the motor controller to change. 3. Speed closed-loop control, is based on the PID algorithm, thus to control the steady speed of the motor controller. 4. Position closed-loop control: it is based on the PID algorithm, so as to effectively control the rotation of the motor controller position. To sum up, all the drive mode of speed control in brushless motor controller whether understand.