A study on the electric and magnetic circuit of single phase line start permanent magnet motor

Recently, as the request of improvement on efficiency for the household appliances increases, a single-phase line-start permanent-magnet synchronous motor (LSPM) attracts attention. LSPM has the capacitor connected in series with the auxiliary winding and the main winding is connected in parallel with them. For this reason, the elliptic rotating magnetic field is generated by converting single-phase into quasi-two-phase. Because of the negative-sequence component in a capacitor motor, secondary current flows also in steady state. So its numerical analysis is difficult in comparison with three-phase motors. Though analytical methods of starting and synchronous characteristics have been established, the effect of considering squirrel cage into analysis has yet to be discussed. In this paper, phaser diagrams that disregard and consider the squirrel cage are presented, and the effect of rotor cage on analytical results is discussed.