Omar Bouhali

Adaptive neural network control based on neural observer for quadrotor unmanned aerial vehicle

This paper proposes an adaptive neural network control with neural state’s observer for quadrotor. The adaptive approach is used to solve the dynamics uncertainty problem of the controller. To perform the control, a Single Hidden Layer Neural Network (SHLNN) is used. Based on the structure of Sliding Mode Observer (SMO), a new neural observer is proposed to estimate the states. The aim of this work is to propose an observer insensitive to the measurement noise. The stability proof of global system is made by Lyapunov direct method. The adaptation laws of both artificial neural networks (ANNs) are derived from Lyapunov theory. The proposed controller is validated by simulation on the quadrotor under measurement noise conditions. A comparative study with SMO is made to highlight the performances of the proposed neural observer. Graphical Abstract

Practical power control design of a NPC multilevel inverter for grid connection of a renewable energy plant based on a FESS and a Wind generator

In this paper we present a modelling of power flows into a power station. This one is based on a variable speed wind generator coupled with a flywheel energy storage system. A multilevel NPC converter is used for the grid connection. The design of the power controller is obtained by a dedicated inversion of the used power model. It includes the strategy for regulating the energy storage in order to supply required active and reactive power references

Direct generalized modulation of electrical conversions including self stabilization of the DC-link for a single phase multilevel inverter based AC grid interface

The output voltage waveform of a multilevel inverter is composed of several intermediary voltage levels, which are obtained from capacitor voltage sources. If the number of levels reaches infinity, the total harmonic distortion of the modulated voltage becomes practically zero. However, the numbers of the achievable voltage levels are limited by voltage unbalance problems, voltage clamping requirement, circuit layout, and packaging constraints. This paper presents a modulation strategy that enables to copy directly a modulated multilevel waveform on to output voltages of a (n+1) level inverter. The redundancies of different switch configurations are used to perform the voltage balancing of the DC link. The obtained modelling shows that high voltage multi levels are obtained by combination of n different three-level functions, which are called modulation functions. Therefore, a novel PWM strategy is designed to generate n fictive modulated voltage systems via the direct width modulation and the position setting of modulation functions. Simulation results are presented for a five-level inverter. Experimental results are given for a three-level inverter.

A five-level diode clamped inverter with self-stabilization of the DC-link voltage for grid connection of distributed generators

In this paper, a new control system for single phase five-level diode clamped inverters (DCI) is presented. The obtained modeling shows that high voltage multilevels are obtained by combination of four different three-level functions, which are called conversion functions. Therefore a novel PWM strategy is designed by a particular modulation for creating four fictive modulated voltage systems via the direct width modulation and the position setting of both conversion functions. Redundancies of different switch configurations for the generation of intermediate voltages are used to limit the deviations of capacitor voltages. A correct filtered AC output is obtained with a classical closed loop control. Experimental and simulation results for a three-level and five-level diode clamped inverter are presented to demonstrate the validity of the proposed balancing modulation.

A New Modeling and Control of a Five Level Three-Phase Diode Clamped Inverter with Self-Stabilization of the DC Link Voltage

In this paper, the direct modulation strategy of a three-level inverter with self stabilization of the DC link voltage is extended to a five-level inverter. Therefore, a new modeling and control strategy of a five-level three-phase Diode Clamped Inverter (DCI) is presented. The obtained modeling shows that modulated multilevel voltages are obtained by combination of eight different three-level functions, which are called modulation functions. Therefore, a space vector scheme without using a Park transform is explained. Based on this algorithm, the location of the reference voltage vector can be easily determined. Then, the voltage vectors are selected to generate corresponding levels and simultaneously their durations are calculated. Moreover, the redundancies of different switch configurations for the generation of intermediate voltages are used to limit the deviation of capacitor voltages. Simulation results for a five-level three-phase Diode Clamped Inverter are presented to show the good performance of the proposed balancing modulation.

Line-to-line Voltage Space Vector Modulation for Neutral-point Clamped Multi-level Converter with DC-link Capacitor Voltage Balancing Using Redundant Vectors

Abstract This article presents space vector modulation of line-to-line voltage for the three-phase neutral-point clamped n-level converter with DC-link capacitor voltage balancing using redundant vectors. The developed modulation strategy is based on an equivalent matrix structure of the neutral-point clamped n-level converter. The relation between the 3 × (n – 1) switching functions of the matrix converter and gate signals of transistors of the neutral-point clamped n-level converter is given. A line-to-line space vector modulation strategy for a matrix inverter is used to obtain the switching function. For one switching function, there is more than one combination to produce each output voltage. Thus, redundancies of different switch configurations for generation of intermediate voltages are used to limit the deviation of capacitor voltages. The gate signals of the neutral-point clamped n-level converter can be calculated by inversing the modeling parts. Here, line-to-line voltage space vector modulation for a neutral-point clamped n-level converter is designed without using a Parks transform. Moreover, n × (n – 1) redundant vectors are used for DC bus voltage balancing. To highlight the performances of the developed modulation strategy, simulation results are given for five- and seven-level neutral-point clamped converters. Experimental results are given for a neutral-point clamped three-level converter.