A method for the pwm drive of a brushless motor with a digitally stored voltage profiles and reduced losses

摘要

A method of driving a multiphase brushless motor with N star-connected windings wherein all the N windings are driven according to a certain predefined periodic voltage profile intended as the differential voltage between the winding's terminal and the star center, includes cyclically keeping for a certain time interval one of the N windings in a fixed state of low or high saturation by applying to the other N-1 phase windings instantaneous voltages according to a profile such that the modulated voltage of the star center subtracted or added to the low or high saturation voltage applied to the terminal of said one winding produce a resultant voltage on the winding of a value coherent with said predefined voltage profile. The number of intervals, in an entire electric period, in which said fixed high or low saturation state of one winding is produced, depends on the predefined driving profile and upon the number N of windings of the motor. IMAGE IMAGE