Combined 3-D-2-D finite element analysis of induction motors considering variation of neutral point potential in star connection

This paper describes a procedure of numerical calculations to obtain characteristics of induction motors considering time-harmonics of the neutral point potential in star connection, which can be utilized as a speed estimator for the control of the motors. The star connection of the motor windings is considered by the primary circuit equations whose known quantities are UV and VW line voltages of three-phase power supply. The equations are coupled to the combined time stepping 3-D-2-D finite element analysis. The frequency domain analysis is also applied to obtain initial value of the time stepping analysis in order to obtain the characteristics at steady rotation quickly.