Energy efficiency optimisation in synchronous reluctance motor drives

A method for energy efficiency optimisation of synchronous reluctance motor drives is presented. The proposed method is implemented both in current vector and voltage source V/f controlled schemes. Based on theoretical considerations, two optimal efficiency conditions that determine the optimal air-gap flux and the optimal d-axis current for the two control schemes are derived. The proposed controllers do not affect the cost and the complexity of the drive. Moreover, they are easily implemented, since an experimental procedure is used to determine their parameters, and therefore knowledge of the loss model is not required. Experimental results are presented to validate the proposed control methods and the resulting improvements.