Abstract: The method and a related device are for driving a brushless motor, according to which by acting solely on the control value, that is by reducing or increasing it, the driving mode eventually passes from a sinusoidal three-phase driving mode to a distorted square-wave three-phase driving mode for increasing or maximizing the voltage that may be supplied to each motor winding or vice versa. An effective drive voltage profile includes, cyclically, during each 60 electrical degree interval, profiles of re-constructed outphased complete drive waveforms including a first one stably in a saturated region, a second one exiting, at the beginning of the interval, a state of incipient saturation, and a third one reaching, at the end of the interval, a state of incipient saturation. In this way, by modifying the numerical control value it is possible to pass from a sinusoidal drive mode to a distorted drive mode of enhanced maximum peak value or vice versa.

Abstract: An open-loop driving method of a spindle motor includes determining of whether open-loop driving conditions for the spindle motor are met, and adjusting widths of driving pulses applied to the spindle motor according to a predictive speed variation of the spindle motor when it is determined that the open-loop driving conditions for the spindle motor are met.