Effect of Direction and Shape of Rotor Conductor Bars on Parameters of Line-Start Synchronous Reluctance Motor

Abstract

Three-phase line-start synchronous reluctance motor (LS-SynRM) combines the structural features of three-phase squirrel cage induction motor (SCIM) and synchronous reluctance motor, it can start up by asynchronous torque from the rotor conductor bars, and running by reluctance torque due to the flux barrier in synchronization. This paper briefly introduces the steady-state characteristics of LS-SynRM, and a new simulation method is presented to determine whether the rotor conductor bars of LS-SynRM is designed properly. The reason why the traditional rotor conductor bars has poor d-axis inductance is analyzed, and proposes a new structure of the rotor conductor bars to improve the d-axis inductance of LS-SynRM. Then the parameters of the proposed conductor bars LS-SynRM is calculated by finite element analysis (FEA), and the inductance difference of $d-q$ axis $(L_d-L_q)$ is increased by 29.7% than the traditional model when the stator current is 4A. Finally, we make the prototypes and measure the performances of them. The efficiency of the proposed LS-SynRM prototype is improved by 1.6% compared with the traditional LS-SynRM prototype and by 2.3% compared with the SCIM at rated torque. The effectiveness of the proposed rotor conductor bars in this paper was verified by the prototype test.