What are the similarities and differences between the dc brushless and the ac brushless motor?
General use on the generator excitation, brushless dc brushless ac motor is generally, also have a plenty of a brush, a motor is generally small motor brush, because of the need to solve the short circuit current of commutation time, so communication has the motor will not be too big, just imagine the dc motor, dc motor and reversing problems, so the dc motor will not do! Dc brushless motor actually is ac motor, commonly used in generator excitation system!
So-called no brush, brushless, is also is this kind of motor does not rely on brush to change the polarity of the armature current, and usually by position detection device, such as hall, the light code disc detection such as location, and then in accordance with a certain control method, according to the position signal to change the polarity of the armature current.
The brushless DC (BLDC) and the brushless AC (the name for which the name doesn't seem to be used in Chinese) belong to the permanent magnet synchronous motor. The two types of motors do not depend on the armature current and the waveform of the anti-electric potential. If the inverse voltage and the armature current are the rectangular wave, that's the BLDC, if it's a sine wave, that's the BLAC. Of course the inverse electric potential is a rectangle and the current of the sine wave, becomes the BLAC operating mode, so the waveform of the current is seen in the end.
