Switched reluctance (SR) machine has various desirable features, which comes from its simple construction. They are the wide speed range, high temperature operation and small moment of inertia. But without any precise control technique no from these advantages could be utilised. SR machine in generating mode also starts to be used and its control technique can be even simpler than in motoring mode. In this paper a drive with a small 6/4 SR machine with an asymmetric half-bridge power converter produced as a motor, will be changed to generator. To obtain this the control technique based on DSP as well as the drive set-up will be modified. The appropriate control technique for obtaining generating mode will be designed and implemented for SR machine control. Generator operation will be tested by various load and speed conditions. Simulation results will be done for the purpose of comparing with those measured.

This paper proposes a scheduling model for ensuring delay as a Quality of Service requirement in the communications network. Different delays are allocated for different pricing classes, say gold, silver, and bronze classes. Our purpose is to minimize weighted mean delay for connections, where weights are the pricing factors of different classes. An adaptive and optimal solution is derived for weights of the scheduler. Simulations show that in addition to the mean delay minimization, the revenue of the service provider is also maximized in the linear pricing scenario. In addition, adaptive updating rule is simple to implement, since it converges fast. Our scenario is independent on the statistical assumptions, and therefore it is robust against possible erroneous estimates of the customers' behavior.

The principal objective of this paper is to present a determination calculation program of the exact profile of the level of radionoise of existing lines E.H.V and on project according to the frequency. The method used for the determination of the disturbing field is an analytical method based on the theory of the modal propagation. We present a calculation program based on MATLAB with examples of real lines.

Direct Torque Control of inverter-fed Induction Machine allows high dynamic performance by means of very simple control schemes. In this paper various direct torque control methodologies as conventional DTC (C_DTC), modified DTC (M_DTC) and twelve sectors (12_DTC) have been analysed and compared in order to evaluate the influence of the motor operating condition on steady state performances. A particular emphasis on stator flux trajectory, torque ripple and stator current distortion has been made. Simulation results show the effectiveness of the proposed methods.

The problem of electric field grading in cable components, having both theoretical and technological implications, can be framed in more general topic of field control in HV equipment. A solution may be obtained by two possible approaches: using geometric field control [11, 13, 14, 15, 17, 18], in which the field distribution depends on the arrangement of main and auxiliary electrodes or using resistive-capacitive (RC) field control [2, 4, 6, 10, 12 ], where the field distribution relies mainly on the electrical characteristics of stress grading materials. The above considerations are applicable to a wide class of MV and HV electrical devices such as insulators, bushings, spacers, voltage deviders, cable accessories (joints and terminations), etc. In the following, paper attention will be focused on the cable terminations and joints. At the places of cable connections and endings exterior cover is removed, and the radial character of electric field is disturbed. Because of high voltage, the inhomogeneous electric field exists on those parts of the cable, having the highest intensity at the ends of the covers, or screen. Cable joints and terminations represent the weakest part of a HV cable power line because of the electric field enhancement at the edge of the truncated conductors and dielectrics. The results for electric field and potential distribution at the coaxial cable terminations and joints, having exponential or ellipsoidal form, obtained by the Equivalent electrodes method (EEM), are presented in this paper. The EEM and Finite elements method (FEM) are compared. Equivalent electrodes (EE) are appointed on the end of coaxial cable, where the edge effect exists. At the great distance from terminations and joints, inside the cable, it may be considered that the field is approximately homogeneous and the charge distribution is continuous. At the cable splice, it is possible to solve the problem (electric field and electric potential distribution) as superposition of two components: the first one originates from continuous distribution of the electrical charge, and the second one from equivalent electrodes.

In this paper, we propose a sliding mode technique to control the field-oriented induction machine. Our aim is to make the speed and the flux control robust to parameter variations. The variation of motor parameters during operation degrades the performance of the controllers. The use of the nonlinear sliding mode method provides very good performance for motor operation and robustness of the control law despite the external/internal perturbations. The chattering effects is eliminated by a particular function "sat" that presents a serious problem to applications of variable structure systems. Simulation results are given to highlight the performance of the proposed control technique under load disturbances and parameter uncertainties.

This paper presents a high performance tracking of maximum power delivered from photovoltaic generators using adaptive neural fuzzy inference systems ANFIS. The non-precise and uncertain behaviour of the climate require stochastic modeling. This hard and hazardous task consumes more computation. Fuzzy logic is the powerful tool for modeling uncertainty and approximate reasoning, however, the presence of expert is the most important part of the design. Expertless design requires data which must cover all the possibilities of operation. Neural networks are the best learning machines in the field. ANFIS combines the advantages of fuzzy logic and neural networks in one package and gives an optimized fuzzy inference system embedding the whole knowledge of the system behaviour (tracking operation). Hysteresis current controller is implemented in order to shape the current to be interfaced to the public grid.
Simulation results carried out from MATLAB demonstrate the success of the technique giving thus high efficiency of the proposed controller.
 
 

In this paper, an optimal fuzzy gain scheduling of PI controller is adopted to speed control of an induction motor. First, a designed fuzzy gain scheduling of PI controller is investigated, in which fuzzy rules are utilized on-line to adapt the PI controller parameters based on the error and its first time derivative. However, the major disadvantage of the fuzzy logic control is the lack of design techniques, for this purpose we propose an optimization technique of the fuzzy logic adapter parameters using genetic algorithm. The effectiveness of the complete proposed control scheme is verified by numerical simulation. The numerical validation results of the proposed scheme have presented good performances compared to the fuzzy controller which have parameters chosen by the human operator.

The study of the Power flow is very significant, because it makes it possible to provide information of large importance; in order to better plan, to control and ensure finally the correct operation of the electrical supply networks. In our article, we present a method of calculation of the flow of powers in a mixed electrical supply network in high voltage (AC/DC). This method called also method SPI: (Substituted Power Injection) makes a small modification to the level of the bus of connection DC. The calculation of the active and reactive powers at the final bus of system AC-DC, are obtained by the subtraction of the powers of the converters and those which are specified with the bus of connection DC. This method will be applied to the 14 bus networks.