Abstract-The use of six-phase induction motor for industrial drives presents several advantages over the conventional three-phase drive such as improved reliability, magnetic flux harmonic reduction, torque pulsations minimization, and reduction on the power ratings for the static converter. For these reasons, six-phase induction motors are beginning to be a widely acceptable alternative in high power applications. A typical construction of such drives includes an induction machine with a dual three-phase connection, where two three-phase groups are spatially shifted 30 electrical degrees, a six-leg inverter, and a control circuit. By controlling the machine's phase currents, harmonic elimination and torque-ripple reduction techniques could be implemented. This paper describes a technique of injecting third harmonic zero sequence current components in the phase currents, which greatly improves the machine torque density. Analytical, finite-element, and experimental results are presented to show the system operation and to demonstrate the improvement on the torque density.Index Terms-Induction machine analysis and design, industrial drives, six-phase drives.

Abstract-The use of six-phase induction motor for industrial drives presents several advantages over the conventional three-phase drive such as improved reliability, magnetic flux harmonic reduction, torque pulsations minimization, and reduction on the power ratings for the static converter. For these reasons, six-phase induction motors are beginning to be a widely acceptable alternative in high power applications. A typical construction of such drives includes an induction machine with a dual three-phase connection, where two three-phase groups are spatially shifted 30 electrical degrees, a six-leg inverter, and a control circuit. By controlling the machine's phase currents, harmonic elimination and torque-ripple reduction techniques could be implemented. This paper describes a technique of injecting third harmonic zero sequence current components in the phase currents, which greatly improves the machine torque density. Analytical, finite-element, and experimental results are presented to show the system operation and to demonstrate the improvement on the torque density.Index Terms-Induction machine analysis and design, industrial drives, six-phase drives.

No abstract

Abstract-The use of a coaxial current transformer (CCT) is an interesting choice for pulsed measurement of current through power devices during switching transients. The CCT is used to reflect current for convenient external measurement with minimal insertion impedance in the critical power circuit. This paper analyzes the characteristics of the CCT and explains how it can be integrated into test setups for both press-pack and module packages. Finite-element techniques are applied to the study of the CCT to obtain detailed electrical and magnetic characteristics. Current distribution in the primary and secondary circuits, flux densities, and insertion inductance and resistance are among the design information that can be obtained through finite-element analysis. Analytical and numerical results are obtained for the proposed CCT that is integrated in test setups for MOS turn-off thyristors (press-pack) and high-voltage insulated gate bipolar transistors (module) characterization.