Field oriented control of five-phase synchronous reluctance motor drive with flexible 3/sup rd/ harmonic current injection for high specific torque

It is shown that third harmonic current injection can produce higher shaft torque than conventional sinusoidal current regulation in five-phase synchronous reluctance machines with salient-pole rotors. This paper investigates the field oriented control (FOC) including the hysteresis-type PWM current regulator of such machines under flexible third harmonic current injection. It is concluded that the sinusoidal current injection can be viewed as a special case of combined fundamental plus third harmonic current injection with 0 percent of third harmonic current. The flexible FOC control algorithm is designed and the developed model is confirmed by the simulation results in Matlab/Simulink environment. The complete strategy has been implemented on a digital signal processor based five-phase synchronous reluctance motor drive fabricated in the authors´ laboratory. The experimental results verify the developed flexible fundamental plus third harmonic FOC.