Fully equipped half bridge building block for fast prototyping of switching power converters

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Effect of Multilevel Inverter Supply on Core Losses in Magnetic Materials and Electrical Machines

The effect of multilevel inverter supply on power losses in magnetic cores and electrical machines is studied. A dynamic numerical model for the hysteresis, eddy current, and excess losses in a core lamination is first developed. By both measurements and simulations for a ring-core inductor, we demonstrate how increasing the number of inverter voltage levels decreases the iron losses when compared with traditional two-level supply. Although the switching frequency has a significant impact on the iron losses in the case of a traditional two-level inverter, using three or five voltage levels makes the losses almost independent of the switching. Finally, finite-element simulations show that simi-lar reductions are also possible for the core losses of 150-kVA and 12.5-MW wound-field synchronous machines, in which rather low switching frequencies are typically used. Calorimetric loss measurements are also presented for the 150-kVA machine in order to confirm the significant effect of switching frequency on the core losses with two-level inverter supply.Peer reviewe

Closure to Discussion on “Effect of Multilevel Inverter Supply on Core Losses in Magnetic Materials and Electrical Machines”

Peer reviewe

Simulating feature-based modelling in programming-by-example parametric CAD

As an alternative to the development of a full feature-based CAD system, we suggest a fairly simple extension to a system that possesses parametric capabilities so that feature-based modelling interface is simulated. We use programming-by-example in defining features by parametric programs following a purely procedural approach. The parametric programs constitute the feature model which is built up in a bottom-up manner. The structuring of the object in feature allows modification to the parametric description in a graphical manner. Some problems related to the use of features in an engineering system for the purpose of simulation and analysis as well as the handling of duality and complementarity in a feature model are discussed. We have restricted our approach to 2D models and have implemented Electric Machinery specific features into a 2D CAD system