Squave-wave Drive and Sine-wave Drive of BLDCM

The phase current of BLDCM, with replacement of mechanical commutation by the use of electrical commutation, can be approximate to square-wave as the traditional DCM; and can also be a sine one. Both of them belong to BLDCM with the characteristics of DCM.Although these two types of driving style are almost with the same mechanical and torque characteristics, the stability, the velocity modulating range and noise are quite different. The sine-wave drive system is much better than the square-wave one. By far the sine-wave drive system is mostly used to the higher requirement application and with a higher price, with can not be a barrier of the sine-wave drive representing the important developing orientation of BLDCM.