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 it. 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, the analytical method of considering the positive and negative sequence phase making use of the method of symmetrical coordinates was proposed. And the experimental and analytical results are compared, and we consider the condition of high efficiency operating from them. In addition, we considered the parameter of load angle. Load angle is very important for single-phase LSPM, but few papers consider it. The load angle is measured by the prototype of single phase LSPM