Feasibility and Energy Efficiency of Frequency Converter Driven Synchronous Reluctance Machine in Crane Application

Abstract

Cranes can use frequency converter driven electrical machines to realize variable speed operations. This thesis discusses if industry favourite induction machine could be replaced by synchronous reluctance machine. Comparative tests have proposed that synchronous reluctance machine is more energy efficient than induction machine. Feasibility of this electrical machine for crane applications needs to be reviewed if this replacement is to be considered. Feasibility and energy efficiency is examined by presenting the operational principles of the compared electrical machines and conducting practical tests with synchronous reluctance machine against a load machine. Presented theory and comparative tests presented no objections against synchronous reluctance machine used for crane application. Practical tests display that synchronous reluctance machine can produce enough torque for crane applications. Tested motor handled zero-speed test cases remarkably well. The motor followed speed commands satisfactorily. Efficiency test results were too low with the tested motor. Efficiency tests faced difficulties, due to which the results are not accurate, but the results can be used to give an indicative view of the efficiency of the tested machine. Synchronous reluctance machine could be used instead of induction machine in cranes, but feasibility requires further research.