Design and analysis of a new improved rotor structure in line-start synchronous reluctance motors

This paper proposes a new design for line-start operation of synchronous reluctance motors. In the past years, synchronous reluctance motors have been studied by many researchers. Due to high efficiency, they have gained increasing interest because in the synchronous operation, there is limited losses in the rotor. On the other hand, line-start operation of the synchronous reluctance motors is an important challenge that can make this type of the motors popular in many applications. However, line-start operation techniques should not considerably affect the steady-state characteristics of the motor. In the proposed design, the arrangement, size and shape of the rotor conductor bars are designed based on the rotor magnetic circuit difference between induction and reluctance synchronous motors. Complete assessment of the motor parameters are examined using finite element analysis. The proposed structure improves the starting characteristics of the motor. Moreover, power factor of the proposed motor is slightly increased in comparison to that of conventional line-start synchronous reluctance motors. The results obviously show effectiveness of the proposed line-start operation strategy for the synchronous reluctance motors. Finally, experimental verification are also included to confirm the finite element analysis results.