Motor drive apparatus and motor system

PROBLEM TO BE SOLVED: To optimize a phase of a driving current of a motor.SOLUTION: A phase calculation unit PHCAL calculates a phase θdrv of the drive voltage for zeroing the phase difference between a reference voltage phase θbemf and a reference current phase θi on the basis of a predetermined arithmetic expression. A phase correction unit PHCP determines a corrected phase θdrvR by adding a correction value to the phase θdrv, and receives the reference voltage phase θbemf and the reference current phase θi as inputs and updates the magnitude of the correction value by feedback control so that the phase difference converges to a predetermined value. The PWM control unit shifts the energization control timing synchronized with the reference voltage phase θbemf on the basis of the corrected phase θdrvR, and generates a PWM signal for controlling the drive voltage in a sinusoidal wave form.SELECTED DRAWING: Figure 6