This paper proposes a method for designing a robust full-order observer for vector-controlled induction motors taking core loss into account. Although conventional research focuses on parameter identification, global stability of the identification remains questionable. Therefore, robustness against some parameters is required. This paper describes the design of a robust full-order observer which takes core loss into account, using both the gain-scheduled H/sub /spl infin// control and the linear matrix inequality technique. This design always results in a stable controller. The robustness of the proposed method against variations of resistances is evaluated by experiments. 相似文献
Thermal stability, mechanism, and kinetics of thermally induced microstructural transformations and their effects on magnetic permeability of Fe72Si15B8V4Cu1 alloy with combined amorphous/nanocrystalline structure were studied. DTA curves revealed two separated thermally activated exothermic events in the temperature ranges from 740 K to 820 K (467 °C to 547 °C) and 870 K to 930 K (597 °C to 657 °C). Crystalline phases present in the as-prepared and thermally treated alloy samples were identified, and their microstructural parameters were determined using XRD, while, to gain further insight into the mechanism of microstructural transformations, AFM and SEM–EDS analyses were performed. Deconvolution of the complex DTA peak into individual steps was conducted, and, in correlation with the results of microstructural analysis, kinetic triplets corresponding to individual transformation steps were determined, allowing for the estimation of the lifetimes of the alloy at different temperatures. Magnetic permeability measurements showed that, in spite of the influence of microstructural transformations on magnetic properties of the alloy, the favorable magnetic properties are retained over relatively a wide temperature range.
The aim of this paper is to establish the correlation among sintering process, porosity, and important thermo-mechanical property
of refractory concrete, i.e., creep. Creep deformation was investigated according to the standard laboratory procedure applied
at three temperatures: 1200, 1300, and 1400 °C. Corundum and bauxite-based refractory concretes were investigated. The concretes
are varying in chemical and mineralogical composition. Both loss of strength and degradation of material occur when refractory
concrete is subjected to increased temperature and compressive static load. Measuring of thermo-mechanical properties can
indicate and monitor the changes within microstructure. Variation of refractory concrete microstructure, as a consequence
of sintering process, during exposure to constant compressive load and constant elevated temperature during certain time-intervals
was investigated using scanning electron microscope and Image Pro Plus program for image analysis. Obtained results of the
investigation proved that creep can be useful method when type of refractory concrete is to be chosen for an application. 相似文献
Wastewater obtained in the production process of wheat starch and vital wheat gluten was treated by microfiltration through a ceramic tubular membrane with 200 nm pore sizes. The consumption of process water would thus be reduced, the starch would be recovered to a greater extent and the wastewater problem would consequently be solved. Reduction of the occurrence of polarization layer on the membrane and the constant wastewater permeate flux through the membrane was maintained by inserting of the mixer Kenics inside the membrane tube. The maximum value of the permeate flux (24 L m−2 h−1) without the use of a static mixer was achieved at 3 × 10−5 Pa and at a flow rate of 150 L/h, for wastewater samples initially allowed to settle for 4 h prior microfiltration. Under the very same conditions of the working parameters, the use of a static mixer enables a flux that is up to two or three times more intensive compared to the values obtained without using a mixer. Microfiltration reduces the wastewater dry matter from 11 000 to 4000 mg/L, lessens the chemical oxygen demand by 74%, i.e. from 21 000 to 5100 mgO2/L and significantly decreases the values of the suspended matter, namely from 9000 to 300 mg/L. 相似文献