Study on the Influence of Design and Optimization of Rotor Bars on Parameters of a Line-Start Synchronous Reluctance Motor

The rotor conductor bars of the line-start synchronous reluctance motor (LS-SynRM) make the motor have self-starting capability. The distribution of the rotor conductor bars not only has a great impact on the starting capability, but also affects the steady-state performance of the LS-SynRM. The steady-state performance of the LS-SynRM mainly depends on the inductance parameters. And the distribution of the rotor conductor bars directly affects the variation of the inductance parameters, especially the d-axis inductance. Based on the steady-state characteristics of LS-SynRM, an evaluation method based on finite element analysis (FEA) is proposed to determine whether the rotor conductor bars of LS-SynRM is reasonable. First, the d-axis inductance reference model without rotor conductor bars is established, the target of optimize is to reduce the weakening effect of rotor conductor bars on the d-axis inductance, and the optimal distribution structure of rotor conductor bars is determined. The optimization results show that the d-axis inductance of the determined rotor conductor bars structure in this article reaches 96.2% of the reference inductance and the distribution of the rotor bars achieves better results. It is verified that the improved LS-SynRM has better efficiency, starting capability, and maximum torque than the initial LS-SynRM by FEA and prototype test. At the same time, comparing with the performance of the three-phase squirrel cage induction motor for compressor, it is proved that the improved LS-SynRM has higher efficiency and a good application prospect.