Maximum efficiency drives of synchronous reluctance motors by a novel loss minimization controller considering cross-magnetic saturation

This paper presents a method to maximize the driving efficiency of synchronous reluctance motors having cross-magnetic saturation effect. A novel method to calculate the optimum d- and q-axis currents that minimize the loss is proposed. In this method, an approximation equation for expressing inductance variation and a simple repetition method are employed to consider the cross-magnetic saturation. This method can determine the optimum d- and q-axis currents quickly and automatically, without using two-dimensional function tables. By installing this method in a digital signal processor for motor control, the authors realized a novel loss minimization controller capable of considering cross magnetic saturation. The validity of the proposed method is verified from simulation and experimental results on a 1.1kW flux barrier type synchronous reluctance motor.