Brushless motor controller is adopted in the control type inverter, it is different from general inverter. Adjust its output frequency is not independent, but by installed on the shaft of the synchronous motor rotor position detector control. Whenever the rotor turns a certain position (For example, 90 ° or 120 ° electrical Angle), the position detector to produce the corresponding signal, applied to the corresponding semiconductor components, make the corresponding phase winding electricity, torque is produced. Motor rotor in each turn a pair of poles, semiconductor devices in turn conduction week, inverter output ac change accordingly a cycle. So self-control type inverter output frequency and the rotational speed of the motor is always in sync, there will not be out of step. In the brushless motor controller, inverter consists of a transistor. Because the transistor has the ability to turn off, as long as its base on the control signal disappears, the transistor will shut off by itself, so it is easier to control. In large capacity of brushless dc motor controller, inverter is composed of thyristor. Thyristor is not the ability to turn off, can't remove the trigger signal so that it is shut off. So when current brushless motor controller need to stop, let another common electricity, how to shut off the original pilot of thyristor, the electric current is transferred to a new phase of thyristor, namely the thyristor converter between the problem is the key technique of thyristor motor controller.
