Search

This paper describes a fully analytical approach for iron losses estimation. This method allows us to quantify hysteresis and Eddy current losses in each part of a Switched Reluctance Motor (SRM), the validation of this method is obtained by comparing analytical and experimental phase inductance, the other validation method is based on comparison of static flux densities between this method and finite element method. Analytical air gap permeance model is used in association with analytical expression of magneto motive force (MMF) and current. It allows calculating the flux linked in each part of the SRM. The temporal and frequency characteristics of these fluxes, using static material iron losses under sinusoidal flux density excitation, FFT and correction factors leads to estimate iron losses and their location in the machine. The results show that the major part of the losses are located in the stator especially in the teeths, Hysteresis losses are higher than Eddy current losses in the SRM. As soon as the speed of the SRM increases the Eddy current losses become more important. 8/6 2 kW SRM is used in experimental test bench, Infrared camera placed in front of the lateral face removed just after operation give the thermal signature of these losses and confirm the previous results. Copper losses are located in the winding.

The aim of this article is contribute to the advanced vector control strategy of asynchronous machines. Analyzes of experimental of indirect field-oriented control are presented. In this context, we propose vector control algorithms to provide solutions to the disadvantages of field-oriented control field-oriented control (FOC). The results obtained from various methods of determining the parameters for asynchronous machine are compared. We calculate the various parameters and then we present the technical characteristics of each element of the asynchronous machine; finally, we implement the vector control used as basis of comparison between the simulation under Matlab/Simulink software and experiments. The simulation and experimental tests show that the proposed controller is suitable for medium and high-performance applications.

After improving the electrical performance of a single-phase photovoltaic inverter (previous article), this article aims to model the three-phase photovoltaic inverter of voltage connected to the grid, and the comparison of two improved methods of controlled of this inverter by the vector control PWM (SVPWM) and sinusoidal (SPWM) under non-linear load conditions (NLL). For this and after modeling the converter, we wish to apply the vector and sinusoidal control in order to minimize the losses of the current injected by this converter in the grid. After application of the Park transformations, the d-q components would not be time-invariant in situations where harmonics, resonances or unbalance is present. Control allows indirect control of the active and reactive powers injected into the grid. This strategy is based on decoupling the output currents of the inverter into active and reactive currents using the Park transformation. The PI controllers are implemented in the dq frame (synchronous reference frame SRF) to adjust the grid currents in the synchronous dq frame. To generate the reference current and maintain synchronism between the inverter and the grid, a Phase-locked loop technique (PLL) can be used. The main advantage and objective of this method is to effectively compensate the harmonic current content of the grid current without and with the use of compensation devices. The main objective is to address, in terms of cost, efficiency, power management and power quality, the problems found with Three-phase photovoltaic inverter connected to the grid controlled by SVPWM and SPWM, in order to compared the two methods and obtain a more reliable and flexible Three-phase inverter. The results of simulations of the new SPWM and SVPWM algorithm demonstrate its superior performance compared to the simple sinusoidal pulse width modulation which is previously used with single-phase photovoltaic inverters (previous article [1, 2, 3]). After comparing the results of the two methods vector and sinusoidal commands, we notice that the current THDi of the current for the vector control (SVPWM) is lower than that obtained with the sinusoidal command (SPWM). The effectiveness of these techniques proposed in this article is demonstrated by the simulation results using the MATLAB/ SIMULINK environment.

The brushless DC motors (BLDC) are used in several applications such as electrical cars, medical and industrial equipment, where speed control with high efficiency is required to satisfy specifications regarding load and tracking references variations. In this paper we propose a comparative study between the classical PI controller and a Sliding Mode Controller (SMC) for closed loop speed control of a trapezoidal back-EMF BLDC using a DC/DC buck converter under various load conditions. Simulation results of speed response, torque and current behaviors of the studied BLDC are also presented to support the noted improvements.

In this paper, a new direct torque control (DTC) scheme for a doubly fed induction motor (DFIM) powered by two voltage source inverters is designed and implemented to improve the dynamic response and performance of the system. The conventional DTC scheme of the DFIM is widely used due to its high performance, robustness and simplicity of implementation. However, the electromagnetic torque and the flux controlled by classical DTC have high ripples. To overcome these drawbacks and to ensure fast response and full reference tracking with the desired dynamic behavior and low ripple level, the combined DTC-backstepping control using a backstepping controller is developed and validated; this strategy is based on the Lyapunov theory to ensure a robust control, less sensitivity from machine parameter variation and without overshoot, unlike the classical PI controllers. The proposed DTC scheme will be investigated by simulation tests using Matlab/Simulink and experimental implementation using dSPACE DS1104 board. Results obtained by simulation and experimentation show the effectiveness of the proposed control in terms of rapidity, robustness and stability for the DFIM operating at variable speeds.

The objective of this paper is to analyze the effect of the electrical unbalance caused by the new high-speed railway line (Tangier-Kenitera) built in Morocco. This line will be started by the end of 2018, it will be supplied by two substations at kilometer points (PK10 (Tangier side), PK185 (Kenitera side)). These substations are supplied by high voltage lines (225 kV), from power stations of the electricity provider in Morocco (ONEE). The connection of these substations is between two phases, which will generate an unbalance in current and voltage at the point of common coupling (PCC) in power grid. This unbalance rise as a result of the railway traffic expansion in this high-speed line. The limit value (1%) tolerated by the electricity provider (ONEE) it exceeds [1]. For this purpose, we analyze this unbalance for two horizons by simulation, the first one (horizon 2018), where this high-speed line will start with reduced railway traffic, and in the second horizon (the year 2030), the railway traffic becomes very high.

This paper describes an analytical based method for iron losses estimation in switched reluctance motor (SRM), It is based on analytical flux calculation using airgap permeance. This method is compared to finite element method in term of phase inductance and static pole flux linkage calculation. FFT analysis is applied to each part of SRM flux waveforms to extract the amplitude of the flux density harmonics. Iron losses are estimated in each part of the SRM, the major part of the losses are located in the stator, Hysteresis losses are higher than Eddy current losses in the SRM. Infrared camera is used to locate experimentally the thermal signature of all losses.

Currently, the switched reluctance motor is recognized as a performing engine, due to its high reliability, robustness and low cost.

This paper presents a new approach to the dynamic control of a current source inverter based STATCOM. The state model in the dq-frame is proposed as the basis for control design. The use of a traditional PID controller led to a high frequency oscillation with low damping between the inductance and capacitance of the output filter CSI. The new approach includes a state-feedback control which reduces system instability due to the oscillations introduced by the output filter. Simulations are performed on MATLAB/Simulink to compare the results obtained by traditional PID control and the state-feedback control.

The sub-stations of the high speed railway connected to the high voltage three phase network, are considered as pollutant loads, disrupting power grids. The major problem of these sub-stations is the unbalance caused by the connection between two phases of high voltage network. This connection leads to an unbalanced current, this current is decomposed into two sequences (positive and negative), creating negative sequence voltage in different points of the network. The parallel VSI STATCOM is one of the modern compensation solutions for the negative sequence current. It allows injecting currents in the sub-station connection point in order to get a balanced network. This paper describes the structure, control strategy, and performance of a VSI STATCOM.

This work presents an experimental study of the unbalance compensation caused by the high speed railway substations in the high-voltage power grid with a shunt voltage source inverter based STATCOM. This experimental study is realized on a reduced scale prototype. The Control of inverter is implemented in a DSP card. The practical results presented in this paper are shown the performance of unbalance compensation by VSI_STATCOM in static and dynamic regime.