Aspects of the control of synchronous reluctance machines including saturation and iron losses

The authors consider aspects of the control of synchronous reluctance machines driven from an inverter when the effects of saturation and iron losses are taken into account. The control strategies considered are maximum torque control (i.e. maximum torque per ampere), maximum power factor control, maximum rate of change of torque control, maximum efficiency control, and field weakening control. A general observation about all the strategies considered is that the current angle of operation is usually large, so that the saturation in the D axis inductance is minimal, even for the higher output powers. This indicates that the identification of the saturated values of the L_d inductance may not be required in a practical controller. The iron loss resistance, on the other hand, plays a crucial role in determining the optimum angles of operation