Patent ID: 7834568

Claim:
A method of driving a three-phase brushless motor wherein 120 electrical degree out-phased voltage waveforms are synchronously produced on three phase windings of the motor, the method comprising: storing numerical values in a memory corresponding to digitized sample values of at least a portion of a periodic profile; reading the numerical values from the memory and applying a numerical control value to each numerical value to generate resulting numerical values; reconstructing out-phased drive voltage waveforms from the profile portion and converting resulting numerical values thereof into three pulse width modulation (PWM) drive signals to be respectively applied to the windings; wherein the out-phased drive voltage waveforms that are applied to the windings are peak value-related waveforms produced by storing in the memory the digitized sample values of the periodic profile such that cyclically, during each 60 electrical degree interval, profiles of the reconstructed out-phased drive voltage waveforms include a first profile that is stable in a saturated region, a second profile exiting, at the beginning of the interval, a state of incipient saturation, and a third profile reaching, at the end of the interval, a state of incipient saturation; and modifying the numerical control value for passing between a sinusoidal drive mode and a distorted drive mode.