Controller Design Using Ant Colony Algorithm for a Non-inverting Buck–Boost Chopper Based on a Detailed Average Model

In this article, the non-inverting buck–boost converter and its operation modes are scrutinized. The closed-loop stability of the converter in buck and boost modes is analyzed, and the necessity of using an appropriated controller is demonstrated. Then the application of an adapted ant colony optimization to design a feedback controller is proposed, and a controller based on its existing model is tuned. Simulation and experimental results obtained from the ant colony optimization designed controller are then compared with a controller designed with the classic method. Although the simulation and experimental results prove the efficiency of the proposed control approach, a significant difference between controller behavior in practice and simulation is obvious. Finding these differences, more detailed models, including all parasitic elements, in the buck and boost modes are derived. Applying the proposed model in controller design illustrates that the desired performance of the converter can be guaranteed with a simple proportional-integral (PI) controller. The suggested ant colony-based controller is again tuned based on the more detailed model, which improves the performance of the converter system even more. Furthermore, good agreement between analytical and experimental outputs validates the accuracy of the modeling and simulation.     

Untersuchung der Legierung THX 540 (AlMg5Si2Mn) in Abhängigkeit von verwendeten Thixoparametern

In this study the entire thixocasting process was examined. The aim was to optimize the process and thus improve the quality of the as-cast part. To successfully produce a thixocast part, the choice of appropriate alloy composition, the appropriate microstructure within the billet and the appropriate heat treatment of the billets into the semisolid state were found to be critical. In order to determine the influence of the alloy composition on fraction solid, simulations using Thermocalc® were conducted. For the special microstructure of the billets the cell size was examined. To determine the characteristics of the castings the circularity, the intermetallic phases (examined with SEM) and the casting defects were investigated. The casting examined was manufactured for use in the automobile industry.     

Untersuchung von Hochtemperatureigenschaften modifizierter AlSiCu-Gusslegierungen

Within this research one modified AlSiCu master casting alloy has been compared with the norm AlSi9Cu3 casting alloy. These alloys are mainly used in the automotive industry for pistons and cylinder heads. The good castability, the high strength at room and elevated temperatures, the low weight, the good wear resistance, and the low thermal expansion are responsible for these applications.     

Aus der Industrie – Neues von der Montanuniversität – Personalnachrichten – Tagungsankündigungen – Hinweise auf Neuerscheinungen

BHM Verbandsnachrichten

Aus der Industrie – Neues von der Montanuniversit?t – Personalnachrichten – Tagungsankündigungen – Hinweise auf Neuerscheinungen     

Energieeffiziente Wärmebehandlung der Gusslegierungen AlSi7Mg0,3 und AlSi9Cu3(Fe)

In this research work, a modified energy efficient T6 heat treatment was performed on AlSi7Mg0.3 and AlSi9Cu3(Fe) castings produced on pilot scale, where a part of the heat from the casting process was used during solution annealing. Calculations of the possible energy savings showed that the novel energy saving heat treatment can gain up to 260 kJ of thermal energy per kilogram of casting compared to conventional methods. To produce samples of the energy efficient heat treatment, the castings were ejected from the squeeze casting machine at 300?°C and immediately transferred to the annealing furnace and subsequently water quenched and artificially aged.     

Prediction of the spray scrubbers’ performance in the gaseous and particulate scrubbing processes

In this study, the spray scrubber's performance in its two classical applications, i.e. gaseous pollutants scrubbing and aerosol removing processes has been simulated by developing two proper mathematical models. The droplets dynamic behavior has been modeled in the Lagrangian framework in which the PSI-Cell model has been applied to obtain the droplets concentration in each tower increment. In order to apply the Lagrangian approach, a mathematical model has been presented for the classical pressure nozzles. One of the unique advantages of the models is their capability to predict the liquid film formation. Moreover, the droplet size distribution and especially the nozzles’ real locations have been incorporated into the models and their probable effects have been investigated. The effects of liquid film formation on both the gaseous and particulate scrubbing efficiency have been probed as well. After validation of the model by some experimental data from the literature, the effect of different parameters such as nozzle locations, nozzle jet velocity and other parameters have been explained.