Abstract

The variation of permanent magnet flux deteriorates the performance of a torque controlled (TC) system. Without the torque sensor, the magnet flux information is indispensable for controlling the torque of the surface permanent magnet synchronous motor (SPMSM) with vector control. The magnet flux depends on variations of temperature inside of the motor. With the increase of stator winding temperature, the magnet temperature increases and the magnet flux decreases. Therefore, the magnet flux is not treated constantly and thus becomes a big issue to TC. So, the instantaneous value of the magnet flux is needed in any way. This paper proposes the estimation method of the magnet flux based on the adaptive identification used in the SPMSM with the vector control. Even at low speed, the influence of the stator resistance variation is not received easily because the proposed method has the stator resistance estimation function. The effectiveness of the proposed method is demonstrated by experiments.

Key words: SPMSM, magnet flux, vector control, stator resistance estimation, adaptive identification, mathematical model.