A New Control Strategy of Five-Phase Permanent-Magnet Motor Drives with a Third Harmonic Current Injection

In this paper, a five-phase permanent-magnet (PM) brushless dc (BLDC) motor is investigated, which has almost trapezoidal back electromotive force(EMF) due to its concentrated windings. Since the third harmonic component in the magnetic field is utilized, the presented five-phase BLDC motors have a higher torque density over conventional three-phase ones, in which the third harmonic current is injected. This paper proposes a new five-phase transformation system, by which the vector control is easily applicable to five-phase BLDC motors. Finally, the results verify the validity of the proposed method.