Circle-criterion Based Nonlinear Observer Design for Sensorless Induction Motor Control

This paper deals with the design of a nonlinear observer for sensorless induction motor control. Based upon the circle criterion approach, a nonlinear observer is designed to estimate pertinent but unmeasurable state variables of the considered induction machine for sensorless control purpose. The observer gain matrices are computed as a solution of linear matrix inequalities(LMI) that ensure the stability conditions of the state observer error dynamics in the sense of Lyapunov concepts. Measured and estimated state variables can be exploited to perform a state feedback control of the machine system. The simulation results are presented to illustrate the effectiveness of the proposed approach for nonlinear observer design.     

Electrodeposition of lead dioxide on Fe electrode: application to the degradation of Indigo Carmine dye

Journal of Applied Electrochemistry - The modification of an iron electrode was carried out according to the following two steps. In a first step, a cathodic reduction is performed to form a film...     

Effect of tantalum addition on microstructure and optical properties of TiN thin films

Titanium nitride thin films were deposited by direct current magnetron sputtering with various tantalum (Ta) concentrations (2, 4 and 8 at.%). The films were characterized using UV/VIS spectrophotometer. Atomic force microscopy (AFM), high resolution transmission electron microscope (HRTEM) were used to observe the microstructure and X-ray photoelectron spectroscopy was used to investigate the core level and the valence band of the films. It was found that the film with 2 at.% Ta is more reflective in the infrared range and more transparent in the visible region (selective behavior). The AFM showed smooth nanostructured surface for the film without Ta addition. It was found that the films with 2 at.% Ta presented relatively coarser grains with larger roughness and the reflectance are not controlled by the surface morphology. Also, this film presented higher electrical conductivity. HRTEM analysis showed that 2 at.% Ta addition gave rise to well crystallized films with elongated nanocrystallites in comparison with the films having 0, 4 and 8 at.% Ta contents.     

Channel Estimation in Long Term Evolution Uplink Using Minimum Mean Square Error-Support Vector Regression

In this paper, minimum mean square error-support vector regression (MMSE-SVR) is proposed, which is shown to be adequate for the estimation of the long term evolution (LTE) uplink channel with nonlinear features. MMSE-SVR was applied to estimate real channel environments such as the vehicular A channels defined by the International Telecommunication Union (ITU). The simulation results show that the proposed method has a better performance than the least squares support vector machine (LS-SVM) and the standard MMSE with linear and spline interpolation.     

Solar map of India under clear sky conditions

This paper focusses on generation of solar irradiation map under clear sky conditions using r.sun model. Direct Irradiation, diffuse irradiation and global irradiation maps are plotted using programme which was developed in C language. This programme calculates different components of solar irradiation using clear sky model (r.sun). Further Surfer software was used to plot different irradiation maps. All three values (Direct Irradiation, Global Irradiation and Diffuse Irradiation) were compared by IMD values for performing statistical analysis i.e. Mean Bias Error (MBE), Root Mean Square Error (RMSE) and standard deviation. MBE was found within ±10%, RMSE lies within <20% and standard deviation was found to have very low value which indicated good fitting between model results and calculated values. Therefore the r.sun model is good model and can be used for computing solar irradiation for India.     

Boundary stabilisation of the wave equation in the presence of singularities

We study the boundary stabilisation of the wave equation by a nonlinear feedback active on a part of the boundary in geometric situations for which the solutions have singularities. These singularities appear at the interfaces at which the mixed Neumann–Dirichlet boundary conditions meet. Under a simple geometrical condition concerning the orientation of the boundary, we obtain sharp energy decay rates under a general growth assumption on the feedback. We show that the singularities do not affect the energy decay rates and give examples.     

A New Control Strategy of 5-Phase PM Motor under Open-Circuited Phase Based on High Order Sliding Mode and Current References Real-Time Generation

The high quality of electrical power in high power and high reliability applications is a crucial necessity even under fault mode function. However, in these conditions, the quality of the torque is a key feature. To overcome this problem, the multiphase permanent magnet (PM) motors seems to be a very attractive choice. In order to highlight the robustness and reliability of this technology, this paper investigates the control of a five-phase PM motor under an open circuited phase fault conditions. Moreover, a High Order Sliding Mode (HOSM) controller combined to an optimal reference current generation is tested and compared to a PID controller under fault mode conditions. This original control strategy is proposed for faulted conditions. Compared to classical fault tolerant control, this strategy allows a better dynamic tracking of the non-sinusoidal reference currents and leads to a smooth torque with minimal losses even in severe fault conditions. To validate the proposed control strategy, simulation, and experimental results are presented and discussed.