FPGA design methodology for industrial control systems—a review

This paper reviews the state of the art of fieldprogrammable gate array (FPGA) design methodologies with a focus on industrial control system applications. This paper starts with an overview of FPGA technology development, followed by a presentation of design methodologies, development tools and relevant CAD environments, including the use of portable hardware description languages and system level programming/design tools. They enable a holistic functional approach with the major advantage of setting up a unique modeling and evaluation environment for complete industrial electronics systems. Three main design rules are then presented. These are algorithm refinement, modularity, and systematic search for the best compromise between the control performance and the architectural constraints. An overview of contributions and limits of FPGAs is also given, followed by a short survey of FPGA-based intelligent controllers for modern industrial systems. Finally, two complete and timely case studies are presented to illustrate the benefits of an FPGA implementation when using the proposed system modeling and design methodology. These consist of the direct torque control for induction motor drives and the control of a diesel-driven synchronous stand-alone generator with the help of fuzzy logic

Neue Implementierungsmethoden für eingebettete geberlose Motor-Controller basierend auf dem Einsatz von Multi-Core-Mikrocontrollern

Diese Arbeit behandelt den Einsatz von Multi-Core-Mikrocontrollern in softwarebasierten Motor-Controllern zur geberlosen Stromregelung von PMSM. Hierbei werden die Steigerung der Motor-Controller-Performance durch Parallelisierung und die Auswirkungen von Cross-Core-Interferenzen auf das zeitliche Verhalten von Motor-Controllern fokussiert. Es wird eine Generalisierung von geberlosen Stromregelungen durchgeführt, um die allgemeine Parallelisierbarkeit dieser Anwendungen zu beschreiben. Hierauf aufbauend wird gezeigt, unter welchen Rahmenbedingungen eine effektive Steigerung der Regelfrequenz durch Parallelisierung realisierbar ist. Durch die Konsolidierung dedizierter Motor-Controller in ein Multi-Core-System kann Hardware eingespart und dadurch der Energiebedarf um bis zu 50 % gesenkt werden. Eine solche Konsolidierung verursacht regelmäßig Cross-Core-Interferenzen. Um diesem Problem entgegenzuwirken, wird ein Verfahren vorgestellt, das die negativen Einflüsse dieser Seiteneffekte auf die Laufzeiten der Motor-Controller analysiert und quantifiziert. Hierauf aufbauend werden Strategien zur Reduktion der Interferenzen beschrieben und evaluiert. Durch die erzielten Ergebnisse werden Multi-Core-Mikrocontroller als Basis neuer Implementierungsmethoden für Motor-Controller erschlossen. Sie erweitern deren Design- und Implementierungsprozesse, um hier Multi-Core-Mikrocontroller durch Parallelisierung und Konsolidierung effektiv und effizient einzusetzen.This thesis addresses the use of multi-core microcontrollers in software-based motor controllers for the position sensorless control of PMSM. The focus is on increasing the motor controller performance through parallelization and on the effects of cross-core interferences on the temporal behaviour of motor controllers. A generalization of position sensorless current controls is carried out in order to describe the general possibilities to parallelize these applications. Building on this, it is shown under which conditions an effective increase in the control frequency can be achieved through parallelization. By consolidating dedicated motor controllers into one multi-core system, hardware can be saved to reduce energy costs by up to 50 %. Such consolidation causes cross-core interference on a regular basis. To address this problem, a procedure is presented that analyses and quantifies the negative influences of these side effects on the runtimes of the motor controllers. Based on this, strategies for reducing interference are described and evaluated. The results of this work open up multi-core microcontrollers as a base for new implementation methods for motor controllers. They expand the design and implementation processes of motor controllers in order to use multi-core microcontrollers effectively and efficiently through parallelization and consolidation

Multi-Objective Optimisation-Based Tuning of Two Second-Order Sliding-Mode Controller Variants for DFIGs Connected to Non-Ideal Grid Voltage

In this paper, a posteriori multi-objective optimisation (MOO) is applied to tune the parameters of a second-order sliding-mode control (2-SMC) scheme commanding the grid-side converter (GSC) of a doubly-fed induction generator (DFIG) subject to unbalanced and harmonically distorted grid voltage. Two variants (i.e., design concepts) of the same 2-SMC algorithm are assessed, which only differ in the format of their switching functions and which contain six and four parameters to be adjusted, respectively. A single set of parameters which stays valid for nine different operating regimes of the DFIG is also sought. As two objectives, related to control performances of grid active and reactive powers, are established for each operating regime, the optimisation process considers 18 objectives simultaneously. A six-parameter set derived in a previous work without applying MOO is taken as reference solution. MOO results reveal that both the six- and four-parameter versions can be tuned to overcome said reference solution in each and every objective, as well as showing that performances comparable to those of the six-parameter variant can be achieved by adopting the four-parameter one. Overall, the experimental results confirm the latter and prove that the performance of the reference parameter set can be significantly improved by using either of the six- or four-parameter versions.This research was co-funded by the Spanish Ministry of Economy and Competitiveness—project codes DPI2015-64985-R and RTI2018-096904-B-I00—and FEDER Funds, EU. The authors from the University of the Basque Country UPV/EHU are with the “Intelligent Systems and Energy (SI+E)” research group, funded by UPV/EHU—research grant GIU16/54—and the Basque Government—research grant IT1256-19

Precision Control of a Sensorless Brushless Direct Current Motor System

Sensorless control strategies were first suggested well over a decade ago with the aim of reducing the size, weight and unit cost of electrically actuated servo systems. The resulting algorithms have been successfully applied to the induction and synchronous motor families in applications where control of armature speeds above approximately one hundred revolutions per minute is desired. However, sensorless position control remains problematic. This thesis provides an in depth investigation into sensorless motor control strategies for high precision motion control applications. Specifically, methods of achieving control of position and very low speed thresholds are investigated. The developed grey box identification techniques are shown to perform better than their traditional white or black box counterparts. Further, fuzzy model based sliding mode control is implemented and results demonstrate its improved robustness to certain classes of disturbance. Attempts to reject uncertainty within the developed models using the sliding mode are discussed. Novel controllers, which enhance the performance of the sliding mode are presented. Finally, algorithms that achieve control without a primary feedback sensor are successfully demonstrated. Sensorless position control is achieved with resolutions equivalent to those of existing stepper motor technology. The successful control of armature speeds below sixty revolutions per minute is achieved and problems typically associated with motor starting are circumvented.Research Instruments Ltd

Transport coopératif d'un objet par deux robots humanoïdes dans un environnement encombré

Il y a présentement de la demande dans plusieurs milieux cherchant à utiliser des robots afin d'accomplir des tâches complexes, par exemple l'industrie de la construction désire des travailleurs pouvant travailler 24/7 ou encore effectuer des operation de sauvetage dans des zones compromises et dangereuses pour l'humain. Dans ces situations, il devient très important de pouvoir transporter des charges dans des environnements encombrés. Bien que ces dernières années il y a eu quelques études destinées à la navigation de robots dans ce type d'environnements, seulement quelques-unes d'entre elles ont abordé le problème de robots pouvant naviguer en déplaçant un objet volumineux ou lourd. Ceci est particulièrement utile pour transporter des charges ayant de poids et de formes variables, sans avoir à modifier physiquement le robot. Un robot humanoïde est une des plateformes disponibles afin d'effectuer efficacement ce type de transport. Celui-ci a, entre autres, l'avantage d'avoir des bras et ils peuvent donc les utiliser afin de manipuler précisément les objets à transporter. Dans ce mémoire de maîtrise, deux différentes techniques sont présentées. Dans la première partie, nous présentons un système inspiré par l'utilisation répandue de chariots de fortune par les humains. Celle-ci répond au problème d'un robot humanoïde naviguant dans un environnement encombré tout en déplaçant une charge lourde qui se trouve sur un chariot de fortune. Nous présentons un système de navigation complet, de la construction incrémentale d'une carte de l'environnement et du calcul des trajectoires sans collision à la commande pour exécuter ces trajectoires. Les principaux points présentés sont : 1) le contrôle de tout le corps permettant au robot humanoïde d'utiliser ses mains et ses bras pour contrôler les mouvements du système à chariot (par exemple, lors de virages serrés) ; 2) une approche sans capteur pour automatiquement sélectionner le jeu approprié de primitives en fonction du poids de la charge ; 3) un algorithme de planification de mouvement qui génère une trajectoire sans collisions en utilisant le jeu de primitive approprié et la carte construite de l'environnement ; 4) une technique de filtrage efficace permettant d'ignorer le chariot et le poids situés dans le champ de vue du robot tout en améliorant les performances générales des algorithmes de SLAM (Simultaneous Localization and Mapping) défini ; et 5) un processus continu et cohérent d'odométrie formés en fusionnant les informations visuelles et celles de l'odométrie du robot. Finalement, nous présentons des expériences menées sur un robot Nao, équipé d'un capteur RGB-D monté sur sa tête, poussant un chariot avec différentes masses. Nos expériences montrent que la charge utile peut être significativement augmentée sans changer physiquement le robot, et donc qu'il est possible d'augmenter la capacité du robot humanoïde dans des situations réelles. Dans la seconde partie, nous abordons le problème de faire naviguer deux robots humanoïdes dans un environnement encombré tout en transportant un très grand objet qui ne peut tout simplement pas être déplacé par un seul robot. Dans cette partie, plusieurs algorithmes et concepts présentés dans la partie précédente sont réutilisés et modifiés afin de convenir à un système comportant deux robot humanoides. Entre autres, nous avons un algorithme de planification de mouvement multi-robots utilisant un espace d'états à faible dimension afin de trouver une trajectoire sans obstacle en utilisant la carte construite de l'environnement, ainsi qu'un contrôle en temps réel efficace de tout le corps pour contrôler les mouvements du système robot-objet-robot en boucle fermée. Aussi, plusieurs systèmes ont été ajoutés, tels que la synchronisation utilisant le décalage relatif des robots, la projection des robots sur la base de leur position des mains ainsi que l'erreur de rétroaction visuelle calculée à partir de la caméra frontale du robot. Encore une fois, nous présentons des expériences faites sur des robots Nao équipés de capteurs RGB-D montés sur leurs têtes, se déplaçant avec un objet tout en contournant d'obstacles. Nos expériences montrent qu'un objet de taille non négligeable peut être transporté sans changer physiquement le robot

Integrated Feedback Scheduling and Control Codesign for Motion Coordination of Networked Induction Motor Systems

This paper investigates the codesign of remote speed control and network scheduling for motion coordination of multiple induction motors through a shared communication network. An integrated feedback scheduling algorithm is designed to allocate the optimal sampling period and priority to each control loop to optimize the global performance of a networked control system (NCS), while satisfying the constraints of stability and schedulability. A speed synchronization method is incorporated into the scheduling algorithm to improve the speed synchronization performance of multiple induction motors. The rational gain of the network speed controllers is calculated using the Lyapunov theorem and tuned online by fuzzy logic to guarantee the robustness against complicated variations on the communication network. Furthermore, a state predictor is designed to compensate the time delay which occurred in data transmission from the sensor to the controller, as a part of the networked controller. Simulation results support the effectiveness of the proposed control-and-scheduling codesign approach

Sliding Mode Control

The main objective of this monograph is to present a broad range of well worked out, recent application studies as well as theoretical contributions in the field of sliding mode control system analysis and design. The contributions presented here include new theoretical developments as well as successful applications of variable structure controllers primarily in the field of power electronics, electric drives and motion steering systems. They enrich the current state of the art, and motivate and encourage new ideas and solutions in the sliding mode control area

Position estimation and performance prediction for permanent-magnet motor drives

PhD ThesisThis thesis presents a theoretical and experimental development of a novel position estimator, a simulation model, and an analytical solution for brushless PM motor drive. The operation of the drive, the position estimation model of the test motor, development of hardware, and basic operation of inverter are discussed. Starting with the well-known continuous-time model of brushless PM motor, a sampled-data model is developed that is suitable for th6, application of real-time position estimator. An analytical methodo f calculating the steady-stateb ehaviouro f the brushlessP M motor for 1200in verter operation is presentedT. he analysisa ssumesth at the machinea ir gap is free of saliency effects, and has sinusoidal back EMF. The analytical solution is derived for 60" electrical of the whole period. By experimental results, it is shown that the method of analysis is adequate to predict Ihe motor's performance for typical operating points including phase advance and phase delay operation. C) I A computer simulation model for prediction of the performance of brushless PM moto rs is presented. The model is formulated entirely in the natural abc frame of reference, which allows direct comparison of the simulation and corresponding experimental results. The equations and diagrams are put into a convenient form for the simulation and future developments and library modules. The simulation model and corresponding experimental data of the brushless PM motor drive is given. The thesis describes a modem solution to real-time rotor position estimation, which has been subject to intense research activity for the last 15 years. The implemented new algorithm for shaft position sensorless operation of PM motors is based on the flux linkage and line current estimation. The position estimation algorithm has also been verified by both off-line and on-line experiments (accomplished by a DSP, TMS320C30), and a wide range of steady-statea nd transient results have been 0gi0v en including starting from rest. The position estimation method effectively moves the position measurement point in the drive from the mechanical side to the motor's terminals. As well as eliminating the mechanical shaft position sensor, the investigated method can be used for high performance torque control of brushless PM motors. The thesis demonstrates that, in contrast to many other "sensorless" schemes, the new position estimation method is able to work effectively over the full operating range of the drive, and is applicable to a wide range of motor/converter types. Since the hardware is straightforward, only the new position estimation algorithm differentiates a system. Therefore, if a DSP control system is already implemented in the drive, the position estimator can be implemented at low cost.Istanbul Technical University and Higher Education Counci

Design and control of a synchronous reluctance machine drive

This thesis investigates the design, performance and control of a synchronous reluctance machine (Synchrel) drive. The Synchrel machine is proposed for variable speed drives because of its advantages over other machines. The rotor has no cage winding, brushes or slip rings. The torque ripple levels are lower in the Synchrel machine than the switched reluctance machine as it operates from a standard sine wave supply. An axially laminated rotor was designed based on finite element analysis, with the aim of producing the same output power as obtained from an induction motor (M) with a similar stator. Using vector control, the developed torque is controlled by regulating the stator current vector. Two vector control schemes are used, maximum torque per ampere and constant current in the direct axis. The output torque characteristics of the machine have been confirmed by finite element analysis. Slotine's approach of sliding mode control is used for position control of the vector controlled synchronous reluctance machine. A comparison is undertaken between the performance of a fixed gain controller with two sliding mode controllers, for both the regulator and servo cases. Invariant performance is obtained using Slotine's sliding mode control approach, unlike with a fixed gain controller. Robustness to parameter variation is an important feature of this technique. This robustness can be achieved through the control law design, assuming parameter variation bounds are known. These improvements are demonstrated for variations in load inertia. Inductance ripple affects machine performance, for example decreasing output torque and increasing core losses. A state space model for the machine that incorporates this inductance effect, yields drive simulation results that agree with experimental results

Reduction of torsional vibrations due to electromechanical interaction in aircraft systems

With the growth of electrical power onboard aircraft, the interaction between the electrical systems and the engine will become significant. Moreover, since the drivetrain has a flexible shaft, higher load connections can excite torsional vibrations on the aircraft drivetrain. These vibrations can break the shaft if the torque induced is higher than the designed value, or reduce its lifespan if the excitation is constant. To avoid these problems, the electromechanical interaction between the electrical power system and the drivetrain must be evaluated. Past studies have identified the electromechanical interaction and introduced experimental setups that allow its study. However, strategies to reduce the excitation of the torsional vibrations have not been presented. This thesis aims to analyse the electromechanical interaction in aircraft systems and develop an advanced electrical power management system (PMS) to mitigate its effects. The PMS introduces strategies based on the load timing requirements, which are built on the open loop Posicast compensator. The strategies referred as Single Level Multi-edge Switching Loads (SLME), Multilevel Loading (MLL), and Multi-load Single Level Multi-edge Switching Loads (MSLME) are applied to different loads, such as pulsating loads, ice protection system, and time-critical loads, such as the control surfaces. The Posicast based strategies, eliminate the torsional vibrations after a switching event, by the addition of zeros that cancel the poles of the system. For this reason, the knowledge of the natural frequencies of the mechanical system is necessary. Experimentally, the system parameters are obtained through Fourier analysis of the step response and the strategies are applied. A robust analysis of the strategies allows the establishment of the range of uncertainty on the frequencies that allow the proper operation of the strategies. Simulation and experimental results show that the torsional vibrations can be reduced to values close to zero by the application of the strategy. Therefore, the PMS mitigates the electromechanical interaction between the electrical power system and the aircraft drivetrain