Recent Advances in Direct Torque and Flux Control of IPMSM Drives

This paper presents the latest advancements in direct torque and flux control (DTFC) schemes of interior permanent magnet synchronous motor (IPMSM) drives. A novel eighteen-sector based DTFC scheme incorporating a model based loss minimization algorithm is proposed to mitigate the torque ripples and achieve high efficiency as compared to the conventional six-sector based DTFC scheme. Finally, in order to have direct and better control of reducing the torque/flux ripples further, a nonlinear control incorporating motor electromagnetic developed torque and stator air-gap flux linkage as virtual control variables is developed. In conventional nonlinear controller d-q axis currents (i(d), i(q)) are considered as virtual control variables that indirectly controls the torque/flux which may not be suitable for high performance drives. Thus, the proposed work overcomes the major drawback (i.e., torque ripple) of the conventional DTFC based IPMSM drive. Feasibility of the developed DTFC schemes is verified through both simulation and experimental results.