Traditional manufacturing of tape wound cores with low effective permeability involves a cutting step to allow for gapping. While this process is well established, it is not without consequence. Gapped tape wound cores suffer reduced performance in terms of overall magnetic, thermal, and electrical properties. By working with a new class of Cobalt-rich metal amorphous nanocomposite alloys, the permeability can be controlled to a pre-determined value prior to winding into the final desired core shape, thus eliminating the gapping step. This new ability to tune the permeability of a core material opens opportunities to develop magnetic cores with reduced volume and improved thermal management, while eliminating the need for labor intensive gapping processes that also introduce variability and complexities such as fringing flux and excess losses. In this work, we present three permeability profiles (constant, ideally graded, and exponentially graded) in toroidal tape wound cores to allow for the greatest variation and control of the flux density. We also demonstrate the potential for manufacturing of large-scale permeability engineered inductors.

The post silicon era has begun with the introduction of wide bandgap semiconductors. Among wide bandgap semiconductors being researched, Silicon Carbide (SiC) has been shown so far as the best candidate to high power and high voltage applications. SiC have a superior performance compared to its counterpart (Si) and this brings new challenges to vital ancillary components such as transformers, inductors, drivers as well as addressing issues such as leakage, clearance, EMI and material challenges. A particular challenge for the magnetics components are increasing demands being placed upon higher operational frequency and higher operational temperature conditions. This paper briefly discusses the current status of high voltage SiC devices and soft magnetic materials and cores for high power and high frequency (1-50kHz) applications comprised of amorphous and nanocrystaline nanocomposite alloys.

The inherent low switching frequency in medium-voltage alternating-current industrial drives presents power-quality and filter-design challenges. In this paper, four multilevel pulsewidth-modulation methods; phase disposition (PD), switching-loss minimization (SLM), and selective harmonic elimination (SHE) up to the 17th and 29th harmonics, respectively, are considered. The characteristics of long-cable effects on common-mode voltage (CMV) and differential-mode voltage (DMV), inverter losses and efficiency, induction machine voltage, and current harmonics are analyzed. Very little has been published in these quantitative comparisons. It is shown that the SHE method has reduced CMV as compared with the PD and SLM algorithms. Elimination of up to the 29th harmonic achieves the best harmonic performance without needing an output filter, at the expense that the losses are higher with a lower efficiency. Analytical and simulation results using the Piecewise Linear Electrical Circuit Simulation for the power-electronic circuits and MATLAB/Simulink for control systems are experimentally verified with a 1000-hp 4160-V neutral-point-clamped adjustable-speed-drive system that includes a 24-pulse front-end voltage source converter.

The inherent low switching frequency in medium voltage (MV) alternating current (AC) industrial drives presents power quality and filter design challenges. In this paper, four multilevel pulse width modulation (PWM) methods: Phase Disposition (PD), Switching Loss Minimization (SLM), Selective Harmonic Elimination (SHE) up to 17th and 29th harmonics respectively are considered. The characteristics of long cable effects on common mode voltage (CMV) and differential mode voltage (DMV), inverter losses and efficiency, induction machine (IM) voltage and current harmonics are analyzed. Very little has been published in these quantitative comparisons. It is shown that the SHE method has reduced CMV as compared to the PD and SLM algorithms. Up to 29th harmonic elimination achieves the best harmonics performance without needing an output filter, at the expense that the losses are higher with a lower efficiency. Analytical and simulation results using PLECS for the power electronics circuits and Matlab/Simulink for control systems are verified experimentally with a 1000hp, 4160V neutral point clamped (NPC) adjustable-speed drive (ASD) system that includes a 24-pulse front-end voltage source converter.