The permanent-magnet-excited synchronous motor is expanding its usage considerably. It has strong and peculiar saliency of magnetic poles, which causes peculiar torque characteristics. The conventional theories, such as the two reaction theory and the two axis theory are based on the d, q axis method. Although they have been resorted to for a long time, their derivation of the circuit equation is not logical and it seems that they involve approximation and even errors. The author applied the spiral vector method (SV method) to analysis of PMSM and derived the new circuit equations of PMSM, whose solutions revealed new aspect of performances of PMSM.1)-7) This paper reports further developments of SV theory of PMSM; one of them is a new V-curve of PMSM. It is quite different from the V-curve of the conventional theories, and is much more useful.
View full abstract