Motor driving circuit, motor driving method and motor device using the same

A motor driving circuit for driving a brushless motor with a sine wave driving mode in a continuous running phase, the brushless motor comprising a stator with a plurality of windings, a rotor and a plurality of position sensors configured to output different magnetic pole detection signals according to positions of the rotor, the positions of the rotor relative to the stator in the circumferential direction being divided into a plurality of sectors, the motor driving circuit comprising:

• a rotor position identifying module configured to identify a sector k in which the rotor is currently located in and an initial electrical angle θk corresponding uniquely to the sector k;
• a speed calculation module configured to obtain an expected ωk of the rotor in the sector k by calculating the average speed of one or more sectors previous to the sector k;
• and
• a calculation/control module configured to:
• 1) determine a real-time electrical angle θ of the rotor in the current sector based on the expected ωk and the initial electrical angle θk;
• 2) determine a real-time equivalent voltage to be output to the windings according to a predetermined modulation strategy for sinusoidal modulated output voltage and the real-time electrical angle θ;
• and 3) obtain a corresponding pulse modulation driving signal according to the determined real-time equivalent voltage.