Patrice Wira | Université de Haute-Alsace (UHA) (original) (raw)

Papers by Patrice Wira

HAL (Le Centre pour la Communication Scientifique Directe), Jul 1, 2007

European Journal of Electrical Engineering

2022 20th International Conference on Harmonics & Quality of Power (ICHQP)

Robotica, 2021

The article proposes a nonlinear optimal (H-infinity) control approach for a type of underactuate... more The article proposes a nonlinear optimal (H-infinity) control approach for a type of underactuated power-line inspection robots. To implement this control scheme, the state-space model of the power-line inspection robots undergoes first approximate linearization around a temporary operating point, through first-order Taylor series expansion and through the computation of the associated Jacobian matrices. To select the feedback gains of the controller an algebraic Riccati equation is solved at each time step of the control method. The global stability properties of the control loop are proven through Lyapunov analysis. The significance of the article’s results is outlined in the following: (i) the proposed control method is suitable for treating underactuated robotic systems and in general nonlinear dynamical systems with control inputs gain matrices which are in a nonquadratic form, (ii) by achieving stabilization of the power-line inspection robots in underactuation conditions the ...

IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society, 2018

1 A nonlinear H-infinity (optimal) control approach is developed for the problem of the control o... more 1 A nonlinear H-infinity (optimal) control approach is developed for the problem of the control of the spherical rolling robot. The solution of such a control problem is a nontrivial case due to underactuation and strong nonlinearities in the system's state-space description. The dynamic model of the robot undergoes approximate linearization around a temporary operating point which is recomputed at each timestep of the control method. The linearization relies on Taylor series expansion and on the computation of the system's Jacobian matrices. For the linearized dynamics of the spherical robot an H-infinity controller is designed. To compute the controller's feedback gains an algebraic Riccati equation in solved at each iteration of the control algorithm. The global asymptotic stability properties of the control method are proven through Lyapunov analysis. Finally, for the implementation of sensorless control for the spherical rolling robot, the H-infinity Kalman Filter is used as a robust state estimator.

2017 11th IEEE International Conference on Compatibility, Power Electronics and Power Engineering (CPE-POWERENG), 2017

A nonlinear H-infinity (optimal) control approach is proposed for the problem of control of Synch... more A nonlinear H-infinity (optimal) control approach is proposed for the problem of control of Synchronous Reluctance Machines (SRMs). Approximate linearization is applied to the dynamic model of the Synchronous Reluctance Machine, round a local operating point. To accomplish this linearization Taylor series expansion and the computation of the associated Jacobian matrices are performed. The robustness of the control scheme assures that the modelling error due to truncation of higher order terms from the Taylor expansion will be compensated. Next, an H-infinity feedback controller is designed. After solving an algebraic Riccati equation at each iteration of the control algorithm, the feedback gain is computed. Lyapunov stability analysis proves that the control loop satisfies an H-infinity tracking performance criterion. This in turn signifies elevated robustness to model uncertainty and external perturbations. Moreover, under moderate conditions it is proven that the control loop is globally asymptotically stable.

2018 IEEE Industrial Cyber-Physical Systems (ICPS), 2018

A nonlinear optimal (H-infinity) control approach is proposed for turbocharged diesel engines wit... more A nonlinear optimal (H-infinity) control approach is proposed for turbocharged diesel engines with potential use in ship propulsion. The dynamic model of the diesel engine undergoes approximate linearization round a temporary operating point. This is defined at each time instant by the present value of the system's state vector and the last value of the control input vector that was exerted on it. The linearization is based on Taylor series expansion and on the computation of the associated Jacobian matrices. For the linearized model an H-infinity feedback controller is computed. The controller's gain is calculated by solving an algebraic Riccati equation at each iteration of the control method. The asymptotic stability of the control approach is proven through Lyapunov analysis. This assures that the state variables of the diesel engine will finally converge to the designated reference values. Optimal functioning of the diesel engine signifies improved power, reduced polluting emissions and reduced fuel consumption.

2018 International Conference on Electrical Sciences and Technologies in Maghreb (CISTEM), 2018

In this work, a direct power control strategy is applied to control a photovoltaic system acting ... more In this work, a direct power control strategy is applied to control a photovoltaic system acting as a shunt active power filter. The main task of the presented system is to reduce harmonic currents and to ensure reactive power compensation. Ideally, the presented system needs to generate enough reactive and harmonic current to compensate the nonlinear load harmonic in the line. Therefore, to establish that, a DC-DC boost converter is used to interface the photovoltaic generator with the grid, which provides continuous power flow from the PV to the grid through a voltage source inverter. Moreover, a suitable control for both shunt active power filter and DC-DC boost converter are developed, in order to extract the maximum amount of power from the photovoltaic generator and reduce harmonic currents with insuring reactive power compensation. The co-simulation processor in the loop results show that the proposed control method can inject maximum available power of photovoltaic generator to the grid, compensates the load reactive power, low total harmonic spectrum are effectively achieved, tracks rapid variations of load, and keeps the DC-link voltage constant.

2018 5th International Symposium on Environment-Friendly Energies and Applications (EFEA), 2018

The present article proposes an adaptive neurofuzzy control method that is capable of compensatin... more The present article proposes an adaptive neurofuzzy control method that is capable of compensating for model uncertainty and parametric changes of Synchronous Reluctance Machines (SRMs), as well as for lack of measurements for the SRMs state vector elements. First it is proven that the SRM's model is a differentially flat one. This means that all its state variables and its control inputs can be written as differential functions of key state variables which are the so-called flat outputs. Moreover, this implies that the flat output and its derivatives are linearly independent. By exploiting differential flatness properties it is shown that the 4-th order SRM model can be transformed into the linear canonical form. For the latter description, the new control inputs comprise unknown nonlinear functions which can be identified with the use of neurofuzzy approximators. The estimated dynamics of the electric machine is used by a feedback controller thus establishing an indirect adaptive control scheme. Moreover, to improve the robustness of the control loop a supplementary control term is computed using H-infinity control theory. Another problem that has to be dealt with comes from the inability to measure the complete state vector of the SRM. Thus, a state-observer is implemented in the control loop. The stability of the considered observer-based adaptive control approach is proven using Lyapunov analysis.

2018 International Conference on Applied Smart Systems (ICASS), 2018

Processor in the Loop (PIL) is a technique for the validation and verification of control algorit... more Processor in the Loop (PIL) is a technique for the validation and verification of control algorithms on a real DSP board. This paper presents a PIL control implementation of a fully grid connected photovoltaic system for power quality improvement under nonlinear load variations. Moreover, the proposed control technique is based on predictive direct power control (PDPC) method. It reduces harmonics and provides reactive power compensation due to loads non-linearity and sudden variations. The source currents therefore recover a sinusoidal waveform with a unity power factor. Furthermore, the power transferred from the PV system into the utility grid is also increased. PIL co-simulation results prove the efficiency of the proposed implementation of the control algorithm.

The electrical energy produced by photovoltaic (PV) process is inexhaustible, developable everywh... more The electrical energy produced by photovoltaic (PV) process is inexhaustible, developable everywhere and clean. Whatever the conditions, it is desirable to extract the biggest amount of power from the solar panel. This is achieved with the use of a Maximum Power Point Tracking (MPPT) algorithm. Fluctuations in weather conditions (irradiation and temperature) strongly degrade the performance of the photovoltaic module's energy conversion and therefore all the power cannot be transferred to the load. The objective is to study and compare different approaches of MPPT algorithms to evaluate the power extracted under the standard test conditions and varying weather conditions. Results of the performance with all these algorithms are compared under different operating conditions. The results show that the Fuzzy Logic Controller (FLC) is the fastest in terms of stabilization and is followed respectively by Fractional Short-Circuit Current (FSCC), Fractional Open-Circuit Voltage (FOCV),...

IECON 2021 – 47th Annual Conference of the IEEE Industrial Electronics Society, 2021

Open-loop synchronization techniques OLSs can be classified into True (TOLS) and Pseudo or Quasi-... more Open-loop synchronization techniques OLSs can be classified into True (TOLS) and Pseudo or Quasi-OLSs (POLS/QOLS). The TOLS means a system that has no feedback in its structures which results in unconditional stability. Roughly speaking the advanced TOLSs suffers from two main drawbakcks:1) compromising performances under off-nominal frequencies in faulty conditions, 2) inefficiency under large frequency drifts and high computation time. To tackle the problem of frequency adaptivity, the POLS uses a frequency estimator. This technique works efficiently under large frequency drifts even in faulty conditions and benefits from low computation time. However, one of the main challenges in OLS techniques is how to improve dynamic performance without compromising the ability to reject disturbances. In this paper, an enhancement is made to the standard POLS to tackle this problem. The use of a cascade positive fundamental components estimator (PFCE) will allow us to enhance the response time while keeping the phase and magnitude error at their lowest. The mathematical model is presented then simulated. The simulation results validate this proposal.

2021 IEEE 30th International Symposium on Industrial Electronics (ISIE), 2021

Phase Locked Loops (PLL) are crucial for the implementation of frequency controllers in electrici... more Phase Locked Loops (PLL) are crucial for the implementation of frequency controllers in electricity distribution grids, especially since the integration of non-synchronous energy production and storage systems connected to the network by electronic power converters. PLLs are used to synchronize the injection of electrical signals from converters into the distribution grid. In this article, we present the five common PLL models suitable for transient stability analysis and perform a performance comparison for estimating frequency deviations. This comparison is based on the frequency estimation in IEEE 9-bus power systems and the evaluation focuses on accuracy and sensitivity to noise.

IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, 2017

A novel adaptive neurofuzzy H-infinity control approach to feedback control and stabilization of ... more A novel adaptive neurofuzzy H-infinity control approach to feedback control and stabilization of the nonlinear dynamical model of bioreactors used in biofuels production is developed. The form and the parameters of the differential equations that constitute the dynamic model of the bioreactor are considered to be unknown, while there is only knowledge about the order of the system. The model of the controlled system undergoes approximate linearization round a temporary equilibrium which is recomputed at each iteration of the control algorithm. The linearization procedure makes use of Taylor series expansion and the computation of Jacobian matrices. For the approximately linearized model of the bioreactor it is possible to design a stabilizing H-infinity feedback controller, provided that knowledge about the matrices of the linearized state-space description is available. Neurofuzy networks are used to estimate the unknown dynamics of the system and its Jacobians. The computation of the feedback controller's gain comes from the solution of an algebraic Riccati equation taking place at each iteration of the control method, and this allows the implementation of the H-infinity feedback controller. The learning rate of the neurofuzzy approximators is chosen from the requirement the first derivative of the system's Lyapunov function to be always a negative one, thus assuring the stability of the control loop. The global asymptotic stability and the robustness properties of the control method are proven through Lyapunov stability analysis.

International Journal of Power Electronics and Drive Systems (IJPEDS), 2021

The identification of the reference currents constitutes an important part of the control of the ... more The identification of the reference currents constitutes an important part of the control of the active power filter. This part requires an accurate estimation of the frequency, phase, and proper extraction of the load current harmonics. This makes the modeling more difficult and requests a rigorous selection of techniques to be used. For the sake of simplicity, the direct method is motivated by the need for the simplicity and flexibility than the existing techniques such as the instantaneous power theory and diphase currents method. However, this method requires a robust phase-locked loop to extract the unity voltages and a robust controller to estimate the magnitude of the source current. To this end, this paper proposes the hybrid phase-locked loop (HPLL) as a good option mainly because 1) it achieves zero phase error under frequency drifts, 2) Fast dynamic response, 3) totally block the DC offset, 4) From the control point of view, it is a type 1 control system which results in ...

International Journal of Electrical and Computer Engineering (IJECE), 2021

By using the direct torque control (DTC), robust response in ac drives can be produced. Ripples o... more By using the direct torque control (DTC), robust response in ac drives can be produced. Ripples of currents, torque and flux are oberved in steady state. space vector modulation (SVM) applied in DTC and used for a sensorless induction motor (IM) with fuzzy sliding mode speed controller (FSMSC) is studied in this paper. This control can minimize the torque, flux, current and speed pulsations in steady state. To estimate the rotor speed and stator flux the model reference adaptive system (MRAS) is used that is designed from identified voltages and currents. The FSMSC is used to enhance the efficiency and the robustness of the presented system. The DTC transient advantage are maintained, while better quality steady-state performance is produced in sensorless implementation for a wide speed range. The drive system performances have been checked by using Matlab Simultaion, and successful results have been obtained. It is deduced that the proposed control system produces better results th...

European Journal of Electrical Engineering, 2020

Advances in Modelling and Analysis C, 2019

AIP Conference Proceedings, 2016