Determining the Control Objectives of a Switched Reluctance Machine for Performance Improvement in Generating Mode

Abstract

Switched reluctance machines are becoming more prevalent in various motor drive applications due to their simple construction, robust design, fault tolerant operation, and relatively low-cost construction. There are nonetheless some drawbacks to the switched reluctance machines operational behavior which limit its potential market penetration. The electromagnetic torque ripple is one of those limitations. However, unlike most four-quadrant variable speed electric motors, switched reluctance machines need additional control considerations to operate in generating mode to maximize power returned while minimizing torque ripple. The goal of this thesis is to explore different control schemes which are used in motoring mode and compare their performance in generating mode for different operational points. Using the lessons learned from the comparisons in generating mode, key optimizations objectives are established to improve the switched reluctance machines performance for generating applications. A multi-objective optimizer is used to select conduction angles using established objectives of maximizing torque and minimizing torque ripple. The proposed generating-specific objectives are compared to the motoring-specific objectives to validate the generating performance improvement for a wide torque-speed range. Finally, a setup is constructed to validate the generating performance of a 3-phase 12/8 SRM using the new optimization objectives and it is compared with conventional objectives.