Efficiency optimized vector control of synchronous reluctance motor

Abstract

In this paper, efficiency maximized current angle condition in synchronous reluctance motor (SynRM) which minimizes the copper and iron losses is derived based on the equivalent circuit model of the machine. The constraint in obtaining the optimal angle is constant output torque for given operating speed. The efficiency of the motor can be improved by the proposed method especially in the light load condition. For SynRM, torque dynamics can be maintained even with controlling the flux level because the generated torque is directly proportional to the stator current. This is not the case of induction motor since the rotor flux linkage is built up with the rotor time constant. In the proposed algorithm simple iron loss compensation routine is added to compensate the torque nonlinearity due to the iron loss. The proposed algorithm allows the electromagnetic losses in variable speed and torque drives to be reduced while keeping good torque control dynamics. Simulation and experimental results are presented to show the validity of the proposed algorithm.