Comparative performance evaluation of FOC and DTC controlled PMSM drives

Vector controlled drives that known as Field Oriented Control (FOC) and Direct Torque Control (DTC), were initially proposed for induction motor drives but recently they have also been investigated in other motor types. This paper presents detailed comparisons between the FOC and the DTC control schemes for Permanent Magnet Sycnhronous Motors (PMSMs). The advantages and disadvantages of the two control schemes are evaluated in terms of torque and speed behaviors and the analysis has been carried out to illustrate the features of both methods by different load simulation tests. In addition, inverter switching frequencies have been measured and compared to give a new comparison criteria to users. The numerical simulations have showed that the FOC controlled scheme has faster speed dynamic response and it has less torque ripples. When inverter switching frequencies have compared, it must be pointed out that switching freqency of the DTC scheme is about %80 lesser than the FOC scheme.