Stator resistance and speed estimation for five level inverter fed DTFC-SVM of speed sensorless PMSM drive

In this paper, direct torque and flux control strategy with space vector modulation for five-level inverter fed permanent magnet synchronous motor (PMSM) drive is proposed with speed and stator resistance estimation. The speed sensorless operation has gained more attention in PMSM drives as the speed feedback is must for control operation. Among the popular speed estimation methods, model reference adaptive system (MRAS)-based speed estimator is simple and helps to eliminate the use of speed sensor and also provides better speed estimation. However, the MRAS-based speed estimation method is dependent on stator resistance parameter and impacts the speed estimation and causes more error at low speeds. In order to enhance the performance of the drive, the stator resistance also estimated using MRAS-based stator resistance along with speed estimation. The ripple content in the torque makes the drive noisy, less efficient, causes vibrations and heat losses. The multi-level inverters are used to minimize torque ripple contents. Further, the stability analysis of the proposed method under different operating condition with pole-zero approach is also presented. The proposed model is simulated in MATLAB/SIMULINK software under different operating conditions such as no-load, load, reversal speed, and change in speed. In order to show the effectiveness of the proposed model, it is also validated by developing the hardware prototype and results are presented for various conditions.