Norihisa Iwasaki

New vector controller for PM motors which modeled the cross-coupling magnetic flux saturation

A new magnetic-flux saturation model has been developed for permanent magnet synchronous motors. In the new model, simple first-order functions Φd(id, iq) and Φq(id, iq) express the relationships between d-q axis currents and each axis magnetic flux, considering magnetic saturation and cross-coupling effects. Taking advantage of these new features, we developed a current controller that introduced the precise inverse model of the motor using the above function. Furthermore, simulations of the proposed current controller were evaluated under ideal conditions without any modeling error. Moreover, it showed, in principle, that the ideal first-order lag characteristic without the current interference between d-q axes could be realized in the conditions of cross-coupling magnetic flux saturation.

Evaluation of efficiency and temperature rise of permanent magnet synchronous motor depending on magnetic properties

This paper reports a utility of the design method that conducts thermo-magnetic coupling analysis by using a heat equivalent circuit and describes evaluation results of relationship between losses and temperature rise based on magnetic prop- erties. We manufactured and tested prototype motors that were designed with thermo-magnetic coupling analysis and found that reduction of copper loss become of particular importance in order to reduce temperature rise, and total losses of motors.