Abstract

In the conventional torque control (TC) of surface permanent magnet synchronous motor, the estimation of magnet flux becomes a big issue because the variation of permanent magnet flux that deteriorates the performance of torque controlled system. The injection molding machine contains a pressure control which is scarcely used on machine tools. The control of this pressure is very important for the operation of injection molding machine because, it depends on the permanent magnet flux which depends on the variations of temperature inside of the motor. With the increase of armature winding temperature, the permanent magnet temperature increases and the magnet flux decreases. Through that variation, the magnet flux is not treated constantly and then the magnet flux information becomes necessary to keep the pressure constant during the operation. Therefore, it is important to develop a fine force-control system. Generally, in force-control systems, the force information from the environment is detected by a force sensor. However, control systems using force sensors present problems related to signal noise, sensor cost, narrow bandwidth, and other factors. To overcome these problems, this paper proposes the estimation method of the magnet flux and the armature winding resistance based on the adaptive identification used in the SPMSM with the vector control in exchange of Force sensor (load cell). The success of the proposed method is showed by both of simulations and experiments.

Key words: SPMSM, torque control, magnet flux estimation method of vector control, armature resistance estimation, adaptive identification, mathematical model.