Larbi Chrifi-Alaoui

Implementation of a New MRAS Speed Sensorless Vector Control of Induction Machine

In this paper, a novel rotor speed estimation method using model reference adaptive system (MRAS) is proposed to improve the performance of a sensorless vector control in the very low and zero speed regions. In the classical MRAS method, the rotor flux of the adaptive model is compared with that of the reference model. The rotor speed is estimated from the fluxes difference of the two models using adequate adaptive mechanism. However, the performance of this technique at low speed remains uncertain and the MRAS loses its efficiency, but in the new MRAS method, two differences are used at the same time. The first is between rotor fluxes and the second between electromagnetic torques. The adaptive mechanism used in this new structure contains two parallel loops having Proportional-integral controller and low-pass filter. The first and the second loops are used to adjust the rotor flux and electromagnetic torque. To ensure good performance, a robust vector control using sliding mode control is proposed. The controllers are designed using the Lyapunov approach. Simulation and experimental results show the effectiveness of the proposed speed estimation method at low and zero speed regions, and good robustness with respect to parameter variations, measurement errors, and noise is obtained.

Sliding mode control based on field orientation for an induction motor

Sliding mode control is popular method for achieving robust tracking of nonlinear systems. The state is forced onto a manifold in state space by discontinuous control. This manifold is so that staying on it implies convergence to the state space origin. In this paper, the nonlinear sliding mode speed and flux control (SMC) based on field orientation for an induction motor drive is proposed, based on the transformed state coordinate representing the speed and flux magnitude dynamic. With the proposed control of speed and flux amplitude, the controlled induction motor drive possesses the advantages of robustness to parametric uncertainties and disturbances. Finally, some simulation results are given to validate the proposed controllers.

Design and implementation of Sliding Mode Controller with varying boundary layer for a coupled tanks system

In this paper, the nonlinear Sliding Mode Control (SMC) with varying boundary layers is implemented to improve the tracking performance of a nonlinear system. The key feature of the control scheme is the use of varying boundary layers instead of fixed boundary layers, which are usually employed in conventional SMC. The experimental results strongly suggest that the proposed control scheme is capable of improving the tracking precision without causing any chattering. In addition, the new control scheme seems to be very robust against various set point conditions.

Neural classification method in fault detection and diagnosis for voltage source inverter in variable speed drive with induction motor

These days, electrical drives generally associate inverter and induction machine. Thus, these two elements must be taken into account in order to provide a relevant diagnosis of these electrical systems. The aim of this paper is to study the feasibility of fault detection and diagnosis in a three-phase inverter feeding an induction motor. The proposed approach is a neural network classification applied to the fault diagnosis of a field oriented drive of induction motor. Multilayer perception (MLP) networks are used to identify the type and location of occurring fault using the stator Concordia mean current vector. In the case of a single fault occurrence, a localization domain made with seven patterns is built. With the possibility of occurrence of two faults simultaneously, there are twenty-two different patterns. Simulated experimental results on 1.5-kW induction motor drives show the effectiveness of the proposed approach with a classification performance over than 95%.

Second order sliding mode induction motor control with a new Lyapunov approach

This paper, deals with the control and observation of an induction motor using second order sliding-mode technique. We present a new Lyapunov function for the stability analysis. This approach guarantees the same robustness and dynamic performance of traditional first-order SMC algorithms, and at the same time, attenuates the chattering phenomenon, which is the main drawback in the actual implementation of this technique. The magnitude of the rotor flux of the induction motor is determined by the output of the closed-loop rotor flux observer based on twisting algorithm control theory. This technique is proposed for the solution of chattering. Simulation results are presented to validate the effectiveness and the good performance of the proposed control technique.

Adaptive backstepping sliding mode control for hydraulic system without overparametrisation

advance practical applications. Therefore, an adaptive law is proposed to adapt the value of the lumped uncertainty in real time. The main novelty of the developed adaptive control laws is that the number of parameter estimates is exactly equal to the number of unknown parameters throughout the entire coupled tanks system. Consequently, the phenomenon of overparametrisation, a significant drawback of backstepping technique to treat the control of coupled tanks in the previous literature, is eliminated in this study. Finally, experimental results are given to illustrate the tracking performance of interconnected system with the developed adaptive control schemes.

Controller design using second order sliding mode algorithm with an application to a coupled-tank liquid-level system

A method for the design of second-order sliding mode controllers is developed for a coupled two tank system. The Standard Sliding Mode (SSM) controller produces oscillations in the closed-loop system. The newly invented Second Order Sliding Mode Controller (SOSMC) not only retains the robustness properties of the classical Sliding Mode Controller (SMC) but also eliminates the drawback of the SMC that is high frequency chattering due to high frequency switching. The high frequency switching can excite the unmodelled dynamics and makes the system unstable. The work presented in this paper is the super twisting controller design for a coupled two tank system. Robustness of the controllers is analyzed and dynamic bounds for the uncertainty are found for a class of this system. The application of this technique to the two-tank system to solve a robust tracking problem is presented.

Field-oriented control using sliding mode linearization technique for induction motor

In the following paper, we propose a new input-output sliding mode linearization control for induction motor combined with field oriented control (FOC). We develop two loops to control the speed and rotor flux modulus. The first one, inner loop, allows to linearize the system by a choose of closed loop poles to achieve a good linearization. The choice of a particular sliding surface permits to create a link between sliding mode theory and input- output linearization. The second loop, an outer one, allows to modifying the dynamics obtained by the first one using PI controller to guarantee stability and tracking performance of speed and rotor flux modulus. When the rotor flux cannot be measured, a nonlinear sliding mode observer is introduced to estimate the rotor flux. The effectiveness of this new approach has been successfully verified through computer simulations

Sliding mode control with integral corrector: Design and experimental application to an interconnected system

In this paper, a solution is proposed in order to solve the chattering avoidance problem in variable structure control for a class of uncertain non linear systems with external disturbances. This approach is based on Sliding Mode Control (SMC) with integral corrector in the boundary layer to synthesize a robust control system. The stability and the performances of the closed-loop system are proven analytically using the Lyapunov synthesis approach. The proposed methods attenuate the effect of both uncertainties and external disturbances; moreover it attenuates the chattering phenomenon introduced by classical sliding-mode control. The application of this method to the two-tank system illustrates the validity and the performances of this approach. The experimental results are presented and compared in this paper.

Advanced strategy of Demand-side management for photovoltaic-wind energy system

Demand side management is considered as the next evolution of smart grid technology, it can adjust the time and the quantity of the electricity usage either by shifting the demand during the peak hours or by moving the time of energy use to off-peak periods. The objective of this paper is to develop an efficient load side management strategy for photovoltaic-wind hybrid energy system for an isolated house. The strategy aims to control the non-critical loads of the house based on an efficient analysis of the daily load profile of the house and on the climate data. The simulation result shows the effectiveness of the proposed strategy, as it improves the energy balance of the system and eliminates the energy waste.