Investigation of faulty behavior of the sensorless control switched reluctance motor drives

The paper presents the results of studies of abnormal conditions in a switched reluctance drive (SRD) due to failures in control algorithms. It discusses one of the most common control algorithms for these drives without the use of sensors, which is simple and easy to configure. The practical application of this algorithm of control showed that various anomalous phenomena could occur in it, expressed, for example, in a sharp increase in the amplitude of the phase current of the motor, and violation of the switching mode. The reasons for these phenomena are not evident and hard to analyze due to the nonlinearity of this drive. To identify these causes and search for measures to eliminate them, we used simulation in the environment of MATLAB/Simulink. The adequacy and effectiveness of the application of the developed simulation models we confirmed by a comparison of the simulation results and the full-scale experiment on real equipment. Theoretical studies and simulation results are in good agreement with the experimental results.

Comparative Evaluation for an Improved Direct Instantaneous Torque Control Strategy of Switched Reluctance Motor Drives for Electric Vehicles

Due to the expected increase in the electric vehicles (EVs) sales and hence the increase of the price of rare-earth permanent magnets, the switched reluctance motors (SRMs) are gaining increasing research interest currently and in the future. The SRMs offer numerous advantages regarding their structure and converter topologies. However, they suffer from the high torque ripple and complex control algorithms. This paper presents an improved direct instantaneous torque control (DITC) strategy of SRMs for EVs. The improved DITC can fulfill the vehicle requirements. It involves a simple online torque estimator and a torque error compensator. The turn-on angle is defined analytically to achieve wide speed operation and maximum torque per ampere (MTPA) production. Moreover, the turn-off angles are optimized for minimum torque ripples and the highest efficiency. In addition, this paper provides a detailed comparison between the proposed DITC and the most applicable torque control techniques of SRMs for EVs, including indirect instantaneous torque control (IITC), using torque sharing function (TSF) strategy and average torque control (ATC). The results show the superior performance of the proposed DITC because it has the lowest torque ripples, the highest torque tor current ratio, and the best efficiency over the low and medium speed ranges. Moreover, the comparison shows the advantages of each control technique over the range of speed control. It provides a very clear overview to develop a universal control technique of SRM for EVs by merging two or more control techniques.