V/f control of the SPMSM with the stabilizing loop using a reduced order observer

This paper proposes a sensorless V/f control method of the surface mounted permanent magnet synchronous motor without damper windings. Arithmetic computation is simpler than vector control. And the low cost price, dynamics and stability is guaranteed. When the loss of synchronization occurs with the load disturbances, the stability loop with a reduced order observer is applied quickly and accurately to improve the speed error.