Ngac Ky NGUYEN
|Titre||Maître de conférences|
Thématique de recherche
|control and modelling of multiphase drives|
ACLI Revue internationale avec comité de lecture
| Variable Speed Control of a 5-Phase Permanent Magnet Synchronous Generator Including Voltage and Current Limits in Healthy and Open-Circuited Modes|
Electric Power Systems Research, Elsevier, Vol. 140, pages. 507-516, 11/2016, Abstract
FALL Ousmane, NGUYEN Ngac Ky, CHARPENTIER Jean-Frédéric, LETELLIER Paul, SEMAIL Eric, KESTELYN Xavier
This paper proposes a novel variable speed control strategy of a particular 5-phase Permanent Magnet Synchronous Generator (PMSG) in healthy and faulty modes by taking into account the constraints on voltages and currents. These constraints are related to the converter and machine design. The considered faults are open-circuited phases (one phase, two adjacent phases and two non-adjacent phases). A variable speed control strategy is presented, including flux weakening operations. Based on analytical formulations, a numerical computation is proposed to bring out the torque-speed characteristics. This method allows the determination of the current references which ensure the functioning of a 5-phase PMSG at variable speed while keeping phase voltages and currents below their limits. Theoretical, numerical and experimental results are presented. These results are compared in order to validate the proposed approach.
| Real-time Switches Fault Diagnosis based on Typical Operating Characteristics of Five-Phase Permanent Magnet Synchronous Machines|
IEEE Transactions on Industrial Electronics, Vol. 63, N°. 8, pages. 4683-4696, 08/2016, Abstract
TRABELSI Mohamed, NGUYEN Ngac Ky, SEMAIL Eric
A novel centroid-based diagnostic method of the power switches in five-leg Voltage Source Inverter (VSI) is proposed in this paper. Using a vectorial multi-machine description, a five-phase drive presenting an opened switch or an opened phase faults has typical operating characteristics in comparison to classical three-phase drives. Based on such characteristics, this work aims to provide a simple and robust diagnostic process for switches fault regardless of the shape of the back-EMFs (harmonic components) and the transient states due to the load variation. Original theoretical developments are presented. Experimental results are shown to validate the proposed strategy.
| Torque Ripple Minimization in Non-Sinusoidal Synchronous Reluctance Motors Based on Artificial Neural Networks|
Electric Power Systems Research, Elsevier., 06/2016, Abstract
TRUONG Phuoc Hoa, FLIELLER Damien, NGUYEN Ngac Ky, MERCKLE Jean, STURTZER Guy
This paper proposes a new method based on Artificial Neural Networks for reducing the torque ripple in a non-sinusoidal Synchronous Reluctance Motor. The Lagrange optimization method is used to solve the problem of calculating optimal currents in the d-q frame. A neural control scheme is then proposed as an adaptive solution to derive the optimal stator currents giving a constant electromagnetic torque and minimizing the ohmic losses.Thanks to the online learning capacity of neural networks, the optimal currents can be obtained online in real time. With this neural control, each machine’s parameters estimation errors and current controller errors can be compensated. Simulation and experimental results are presented which confirm the validity of the proposed method.
| Fault-Tolerant Operation of an Open-End Winding Five-Phase PMSM Drive with Short-Circuit Inverter Fault|
IEEE Transactions on Industrial Electronics, Vol. 63, N°. 1, pages. 595-605, 01/2016, URL, Abstract
NGUYEN Ngac Ky, MEINGUET Fabien, SEMAIL Eric, KESTELYN Xavier
Multi-phase machines are well-known for their fault tolerant capability. Star-connected multiphase machines have fault tolerance in open-circuit. For inverter switch short-circuit fault, it is possible to keep a smooth torque of Permanent Magnet Synchronous Machine (PMSM) if the currents of faulty phases are determined and their values are acceptable. This paper investigates fault-tolerant operations of an open-end five-phase drive, i.e. a multi-phase machine fed with a dual-inverter supply. Inverter switch short-circuit fault is considered and handled with a simple solution. Original theoretical developments are presented. Simulation and experimental results validate the proposed strategy.
| Adaline for Online Symmetrical Components and Phase Angles Identification in Transmission Lines|
IEEE Transactions on Power Delivery, Vol. 27, N°. 3, pages. 1134-1143, 07/2012, Abstract
YOUSFI F. L., OULD ABDESLAM Djaffar, BOUTHIBA T., NGUYEN Ngac Ky, MERCKLE Jean
This paper presents a new method for online symmetrical components and phase-angle extraction from high-voltage transmission-line faults. This method is based on the Adaline neural networks and the instantaneous power theory, also known as the p-q method. A new current decomposition is proposed in order to derive the direct, inverse, and homopolar current components. The average and oscillating terms of powers in the αβ frame are separated by using four Adaline neural networks. The Adalines use a cosine and sine as inputs in order to learn the linear combination of the powers. The resulting symmetrical components are used by three other Adalines for phase-angle estimation between direct and inverse current components. These phase angles permit classifying the fault types. The neural networks use an online learning process-based Widrow-Hoff algorithm and can adapt their weight parameters to the power-supply evolution. Simulation results show the performance and the robustness of this method and provide a perspective for protection relay improvement.
| Harmonics Identification with Artificial Neural Networks: Application to Active Power Filtering|
International Journal of Emerging Electric Power Systems, Vol. 12, N°. 5, 08/2011, Abstract
NGUYEN Ngac Ky, WIRA Patrice, FLIELLER Damien, OULD ABDESLAM Djaffar, MERCKLE Jean
This study proposes several high precision selective harmonics compensation schemes for an active power filter. Harmonic currents are identified and on-line tracked by novel Adaline-based architectures which work in different reference-frames resulting from specific currents or powers decompositions. Adalines are linear and adaptive neural networks which present an appropriate structure to fit and learn a weighted sum of terms. Sinusoidal signals with a frequency multiple of the fundamental frequency are synthesized and used as inputs. Therefore, the amplitude of each harmonic term can be extracted separately from the Adaline weights adjusted with a recursive LMS (Least Mean Squares) algorithm. A first method is based on the modified instantaneous powers, a second method optimizes the active currents, and a third method relies on estimated fundamental currents synchronized with the direct voltage components. By tracking the fluctuating harmonic terms, the Adalines learning process allows the compensation schemes to be well suited for on-line adaptive compensation. Digital implementations of the identification schemes are performed and their effectiveness is verified by experiments.
ACT Conférence internationale avec acte
| Adaline Neural Networks-based Sensorless Control of Five-Phase PMSM Drives|
IECON' 16, 11/2016, Abstract
NGUYEN Ngac Ky, SEMAIL Eric, DE BELIE Frederik, KESTELYN Xavier
This papers presents a sensorless control for fivephase PM synchronous machines. An adaptive method, based on a linear neural network called Adaline (Adaptive Linear Neural Networks), has been achieved to estimate the rotor position with a high precision even at low speed without high frequency signal injection. Non-sinusoidal three-phase PM machines require more complex algorithm for sensorless control because of harmonics in the back-EMF. This is not the case for multiphase PM machines thanks to the property of equivalent machines in the eigenspace. Some given simulation and experimental results in laboratory confirm the possibility of real-time implementation of Adaline networks and the good performance of sensorless control based on this.
| Open Switch and Open Phase Real Time FDI Process for Multiphase Synchronous Motor|
ISIE’16, IEEE International Symposium on Industrial Electronics, 06/2016, Abstract
TRABELSI Mohamed, NGUYEN Ngac Ky, SEMAIL Eric, MEINGUET Fabien
This paper deals with the real time Fault Detection and Identification (FDI) process of inverter Open Switch Fault (OSF) and Open Phase Fault (OPF) in five-phase PMSM designed for aerospace applications in which the electric drive system has particular operating characteristics either in healthy states or in the faulty ones. Two original contributions are considered in this paper. They consist in normalizing the input variables of the FDI process applied to multiphase system and compensating the noise (switching and sensors noises) and dc-component resulting from the fault occurrence. The proposed strategy uses multiple normalized criterias derived from the measured phase currents and the voltages obtained from the outputs of the current controllers. The FDI shows an independence with respect to the transient states and to the switching and measurement noises. Moreover, it can be easily included in an existing software without any additional sensors. The validity of the proposed method is verified by Matlab/Simulink simulation tests.
| Open Switch Fault Effects Analysis in Five-Phase PMSM Designed for Aerospace Application|
SPEEDAM Symposium, 06/2016, Abstract
TRABELSI Mohamed, SEMAIL Eric, NGUYEN Ngac Ky, MEINGUET Fabien
This paper describes analytical and simulation tools to analyze the effects of Open Switch Fault (OSF) and Open Phase Fault (OPF) on five-phase PMSM designed for aerospace applications. For such applications, the fault tolerance and the reliability of the drive (PMSM and the power converter) are important to take into account for design. The addressed work aims essentially to analyze the dynamic of the measured phase currents in post-fault operation with a real-time fault diagnostic purpose in the VSI. The paper starts with a presentation of the electric drive system structure and its control used in pre-fault and post-fault operation. Then, fault effects analysis (FEA) on the system will be considered. All results are verified analytically and through simulation software using Matlab/Simulink®. The theoretical development and the simulation results show that the five-phase PMSM under inverter faults presents typical characteristics which can be used as better input variables for designing a high performance real-time fault diagnostic and classification process
| Optimal Efficiency Control of Synchronous Reluctance Motors-based ANN Considering Cross Magnetic Saturation and Iron Loss|
Conférence IECON Nov 2015, 11/2015, Abstract
TRUONG Phuoc Hoa, FLIELLER Damien, NGUYEN Ngac Ky, MERCKLE Jean
This paper presents a new idea by using the Artificial Neural Networks (ANNs) for estimating the parameters of the machine which achieving the maximum efficiency of the Synchronous Reluctance Motor (SynRM). This model take into consideration the magnetic saturation, cross-coupling and iron loss. With Finite Element Analysis (FEA), the characteristics of the SynRM including inductances and iron loss resistance are determined. Because of the non-linear characteristics, an ANN trained off-line, is then proposed to obtain the d-q inductances and iron loss resistance from Id,Iq currents and the speed. After learning process, an analytical expression of the optimal currents is given thanks to Lagrange optimization. Therefore, the optimal currents will be obtained online in real time. This method can be achieved with maximum efficiency and high-precision torque control. Simulation and experimental results are presented to confirm the validity of the proposed method.
| Fault Tolerant Dual-Motor Drives: Sizing of Power Electronic|
EPE 2015, 09/2015, Abstract
DOS SANTOS MORAES Tiago José, NGUYEN Ngac Ky, MEINGUET Fabien, SEMAIL Eric
This paper analyzes two dual-motor fault-tolerant topologies. The first one supplies independently both machines while the second one connects them in series for reducing the number of transistors. For a given DC-link voltage, the converter component sizing is based on the peak current obtained in the normal and degraded modes.
| A Comparative Study of Two Fault-Tolerant Dual-Motor Drive Topologies Under Short-Circuit Inverter Switch Fault|
Conférence ISIE 2015, 06/2015, Abstract
DOS SANTOS MORAES Tiago José, NGUYEN Ngac Ky, SEMAIL Eric
This paper analyzes two dual-motor fault-tolerant topologies for aerospace thruster application.The first structure supplies independently both machines whilethe second one connects them in seriesfor reducing the number of transistors and offering a capability of energy management between the sources. Inverter short-circuit fault isconsidered.Based on the peak-currents obtained in simulation in degraded mode without reconfiguration and with two different reconfiguration strategies, the two proposed topologies can be compared in economic and technical aspects.
| Investigation on Model Predictive Control of a Five-Phase Permanent Magnet Synchronous
Machine under Voltage and Current limits|
ICIT 2015, 03/2015, Abstract
KESTELYN Xavier, GOMOZOV Oleg, BUIRE Jérôme, NGUYEN Ngac Ky
The optimal control of electrical drives necessitates to take into account current and voltage limits that are imposed by the power electronics and the electrical machines. Let’s cite for example the flux-weakening operation of electrical drives or propulsion. If the control of classical three-phase drives under voltage and current limits are known for a long time, the specific characteristics of multiphase drives open the way to researches on their control under such constraints. This paper aims to explain what are the main differences between three-phase and multiphase drives when they run under voltage and current constraints and try to show what are the scientific and technical problems to be solved. Some first results are given in order to show that Model Predictive Control (MPC) is expected to be a good candidate to answer the proposed challenge.
| Analytical Optimal Currents for Multiphase PMSMs Under Fault Conditions and Saturation|
Industrial Electronics Society, IECON 2014 - 40th Annual Conference of the IEEE, 11/2014, Abstract
NGUYEN Ngac Ky, FLIELLER Damien, KESTELYN Xavier, SEMAIL Eric
An original analytical expression is presented in this paper to obtain optimal currents minimizing the copper losses of a multi-phase Permanent Magnet Synchronous Motor (PMSM) under fault conditions. Based on the existing solutions [i]opt1 (without zero sequence of current constraint) and [i]opt2 (with zero sequence constraint), this new expression of currents [i]opt3 is obtained by means of a geometrical representation and can be applied to open-circuit, defect of current regulation, current saturation and machine phase short-circuit fault. Simulation results are presented to validate the proposed approach.
| Maximum Torque Per Ampere Control strategy of a 5-phases PM Generator in healthy and faulty modes for tidal marine turbine operation in a large range of speed|
International Power Electronics and Application Conference and Exposition (PEAC 14) (accepted), 11/2014, Abstract
FALL Ousmane, CHARPENTIER Jean-Frédéric, NGUYEN Ngac Ky, LETELLIER Paul
The work presented in this paper aims to propose a control strategy being able to extract efficiently energy from a fixed-pitch marine current turbine associated with a 5–phase Permanent Magnet Synchronous Generator (PMSG) in healthy mode and in faulty mode. The considered faults are opened phases. For each tidal current speed, the control strategy aims to extract the maximum power with respect of the maximum values of currents and voltages related to the converter. The maximum power is directly related to the Maximum Torque per Ampere (MTPA) control strategy characteristics (all the points which are below the MTPA torque VS rotating speed characteristic can be reached by the converter/generator set). This paper proposes a methodology to establish MTPA characteristics and calculate the corresponding current references in healthy mode and in faulty mode (one or two opened phases) for a 5-phase generator. The studied strategy includes flux weakening operations in the both modes.
| Fault-Tolerant Optimal-Current Torque-Controlled Five-Phase PMSMs with Open-Circuited Phases: Position Self-Sensing Operation|
Vehicule Power and Propulsion Conference (VPPC) 2014, 10/2014, URL, Abstract
DE BELIE Frederik, KESTELYN Xavier, NGUYEN Ngac Ky
All-electric vehicles should be made more reliable in such way one can continue driving even after the event of one or more faults in the electrical drive. For this, the use of multiphase (more than 3 phases) electrical machines is considered here due to its redundant feature. An additional technique to increase reliability is to replace sensors by observers. This paper studies the feasibility to control the torque in multi-phase permanent magnet synchronous drives without a position sensor, with the lowest Joule losses, and this for a healthy as well as for a faulty operation with one or more phases open-circuited.
| Fault-Tolerant Operation of an Open-End Winding Five-Phase PMSM Drive with Inverter Faults|
The 39th Annual Conference of the IEEE Industrial Electronics Society, IECON2013., 11/2013, Abstract
MEINGUET Fabien, NGUYEN Ngac Ky, SANDULESCU Alexandru-Paul, KESTELYN Xavier, SEMAIL Eric
Multi-phase machines are known for their fault-tolerant capability. However, star-connected machines have no fault tolerance to inverter switch short-circuit fault. This paper investigates the fault-tolerant operation of an open-end five-phase drive, i.e. a multi-phase machine fed with a dual-inverter supply. Open-circuit faults and inverter switch short-circuit faults are considered and handled with various degrees of reconfiguration. Theoretical developments and experimental results validate the proposed strategies.
| An investigation of Adaline for torque ripple minimization in Non-Sinusoidal Synchronous Reluctance Motors|
Industrial Electronics Society, IECON 2013 - 39th Annual Conference of the IEEE, pages. 2602-2607, 11/2013, Abstract
TRUONG Phuoc Hoa, FLIELLER Damien, NGUYEN Ngac Ky, MERCKLE Jean, STURTZER Guy
This paper presents a new method based on Artificial Neural Networks to obtain the optimal currents, for reducing the torque ripple in a Non-sinusoidal Synchronous Reluctance Motor. Optimal current control has to develop a constant electromagnetic torque and minimize the ohmic losses. In d-q reference frame without homopolar current, the direct and quadrature optimal currents will be determined thank to Lagrange optimization. A neural control scheme is then proposed as an adaptive solution to derive the optimal stator currents. Thank to learning capacity of neural networks, the optimal currents will be obtained online. With this neural control, either machine’s parameters estimation errors or current controller errors can be compensated. Simulation results using Matlab/Simulink are presented to confirm the validity of the proposed method.
| Different Virtual Stator Winding Configurations of Open-Winding Five-Phase PM Machines for Wide Speed Range without Flux Weakening Operation|
Power Electronics and Applications (EPE), 2013 15th European Conference on, pages. 1-8, 09/2013, URL, Abstract
NGUYEN Ngac Ky, SEMAIL Eric, MEINGUET Fabien, SANDULESCU Alexandru-Paul, KESTELYN Xavier
This paper presents a specific control strategy of double-ended inverter system for wide-speed range of open-winding five phase PM machines. Different virtual stator winding configurations (star, pentagon, and pentacle) can be obtained by choosing the appropriated switching sequences of two inverters. The motor’s speed range is thus increased.
ACN Conférence nationale avec acte
| Commande en Mode Dégradé d’un Drive avec Deux Machines 6 phases en Série|
SGE 2016, Symposium de Genie Electrique, 06/2016, Abstract
DOS SANTOS MORAES Tiago José, NGUYEN Ngac Ky, MEINGUET Fabien, SEMAIL Eric
Dans le cadre d’une commande en mode dégradé d’un drive comprenant deux machines polyphasées connectées en série et pilotées de façon indépendantes, l’article s’intéresse à analyser la performance du drive dans le cas d’une reconfiguration complète, c’est-à-dire, une modification de l’algorithme de commande lors d’un défaut en mode dégradé
| Comparaison de performances de différentes structures de machines polyphasées en mode normal et en modes dégradés en vitesse variable avec défluxage pour des applications hydroliennes|
SGE' 16, Grenoble, 06/2016, Abstract
FALL Ousmane, CHARPENTIER Jean-Frédéric, NGUYEN Ngac Ky, LETELLIER Paul
Cet article s’intéresse au dimensionnement de génératrices synchrones polyphasées à aimants permanents destinées à être associées à un multiplicateur de vitesse de faible rapport (qui ne nécessite que très peu d’entretien contrairement au multiplicateurs de rapports élevés) et une turbine à pas fixe. L’objectif est de comparer les structures à bobinage concentré à 5 phases régulièrement réparties et les structures à 2*3 phases, à une structure de référence à 2*3 phases à bobinage distribué classique, afin de voir l’influence du bobinage et de la structure polyphasées choisies, en termes de capacité de fonctionnement en défluxage en mode normal et dégradé pour un même cahier des charges relatif à une génératrice hydrolienne.
AP Autre publication
| A Self-Learning Solution for Torque Ripple Reduction for Non-Sinusoidal Permanent Magnet Motor Drives Based on Artificial Neural Networks|
IEEE Transactions on Industrial Electronics, Vol. 61, N°. 2, pages. 655-666, 02/2014, Abstract
FLIELLER Damien, NGUYEN Ngac Ky, WIRA Patrice, STURTZER Guy, OULD ABDESLAM Djaffar
This paper presents an original method, based on artificial neural networks, to reduce the torque ripple in a permanent-magnet non-sinusoidal synchronous motor. Solutions for calculating optimal currents are deduced from geometrical considerations and without a calculation step which is generally based on the Lagrange optimization. These optimal currents are obtained from two hyperplanes. The study takes into account the presence of harmonics in the back-EMF and the cogging torque. New control schemes are thus proposed to derive the optimal stator currents giving exactly the desired electromagnetic torque (or speed) and minimizing the ohmic losses. Either the torque or the speed control scheme, both integrate two neural blocks, one dedicated for optimal currents calculation and the other to ensure the generation of these currents via a voltage source inverter. Simulation and experimental results from a laboratory prototype are shown to confirm the validity of the proposed neural approach.
| FPGA resources reduction by a multiplexing technique applied on ANN-based harmonics extraction algorithms|
Journal of Energy and Power Engineering, Vol. 6, pages. 469-477, 06/2012, Abstract
DZONDÉ NAOUSSI S. R., NGUYEN Ngac Ky, BERVILLER H., BLONDÉ J.-P., KOM M.
In this paper, a multiplexing technique is applied on a neural harmonics extraction method, based on an efficient formulation of the instantaneous reactive power theory. This approach can be used in nonlinear loads compensation with APFs (Active Power Filters). The architecture for reference current generation, synchronized by a neural phase lock-loop, is composed of three Adaline neural networks. This leads to an important consumption of field programmable gate array resources during implementation. The proposed technique uses only one Adaline and keeps the immunity of the approach under non-sinusoidal and unbalanced conditions of voltage. Simulation results of the neural harmonics detection system connected to a reference current controller show balanced and sinusoidal source currents under various conditions. Results with experimental measurement made on an APF test bench demonstrate its good performances on harmonics filtering. Moreover, the simplified structure from the new approach called mp-q method shows a significant resource reduction.