Modeling and Characteristic Analysis of Line-Start Synchronous Reluctance Motor

This paper investigates the characteristics of a line-start synchronous reluctance motor by extracting its induction torque and reluctance torque, which are by nature out of phase. During the transient period with slips before the rotor reaches a synchronous speed, these two torques overwhelm each other in turn to accelerate the motor. At the synchronous speed when the motor slip is zero, the reluctance torque alone is responsible for driving the motor without losing power in the rotor conductor, thereby improving the efficiency of the motor under external loads. These characteristics are analyzed by the dynamic model and proven via simulations. The maximum reluctance torque was obtained by adjusting the current angle at 45 electric degrees, while the maximum power factor was achieved by setting the current angle at the inverse tangent of the square root of the saliency ratio of the motor.