A Novel DTFC Based IPMSM Drive with Improved Efficiency and Dynamic Performance

This paper presents a novel direct torque and flux control (DTFC) scheme of interior permanent magnet synchronous motor (IPMSM) drive. The conventional six-sector based DTFC scheme is modified with the proposed eighteen-sector based DTFC scheme in order to reduce the torque/flux ripple of the drive. Furthermore, the motor efficiency is optimized by reference flux estimation through an online loss minimization algorithm (LMA) so that the motor operates at minimum loss condition, which is not possible for conventional control where the reference flux remains constant. The complete drive is simulated using MATLAB/Simulink software and then a prototype is implemented using digital signal processor (DSP) board DS1104 for a laboratory 5-hp motor. Performance of the proposed DTFC scheme is investigated extensively at different operating conditions in both simulation and experiment. It is found from results that the proposed eighteen-sector based DTFC scheme incorporating LMA achieves the lowest possible torque ripples in steady state while maintaining high efficiency.