Optimal and robust control for a small-area FLL

International audienceFine-grain Dynamic Voltage and Frequency Scaling (DVFS) is becoming a requirement for Globally-Asynchronous Locally-Synchronous (GALS) architectures. However, the area overhead of adding voltage and frequency control engines in each voltage and frequency island must be taken into account to optimize the circuit. A small-area fast-reprogrammable Frequency-Locked Loop (FLL) engine is a suited option, since its implementation in 32nm represents 0.0016mm 2, being 4 to 20 times smaller than classical techniques used such as a Phase-Locked Loop (PLL) in the same technology. Another relevant aspect with respect to the FLL is the control design, which must be suited for low area hardware. In this paper, an analytical model of the system is deduced from accurate Spice simulations. It also takes into account the delay introduced by the sensor. From this model, an optimal and robust control law with a minimum implementation area is developed. The closed-loop system stability is also ensured

Architecture and Control of a Digital Frequency-Locked Loop for Fine-Grain Dynamic Voltage and Frequency Scaling in Globally Asynchronous Locally Synchronous Structures

International audienceA small area fast-reprogrammable Digital Frequency-Locked Loop (DFLL) engine is presented as a solution for the Dynamic Voltage and Frequency Scaling (DVFS) circuitry in Globally Asynchronous Locally Synchronous (GALS) architectures implemented in 32 nm CMOS technology. The DFLL control is designed so that the closed-loop system is able to cope with process variability while it rejects temperature changes and supply voltage slow variations. Therefore the DFLL is made of three main blocks, namely a Digitally Controlled Oscillator (DCO), a "sensor" that measures the frequency of the signal at the output of the DCO and a controller. A strong emphasis is set on the loop filter architecture choice and the tuning of its parameters. An analytical model of the DCO is deduced from accurate Spice simulations. The delay introduced by the sensor is also taken into account to design. From these models, an optimal and robust controller with a minimum implementation area is developed. Here, "optimal" means that the controller is computed via the minimization of a given criterion while the "robustness" capability ensures that the closed-loop system is tolerant to process and temperature variations in a given range. Therefore, performances of the closed-loop system are ensured whatever the system characteristics are in a given range

Advanced Control Design for Voltage Scaling Converters

International audienceIn low-power electronics, achieving a high energy efficiency has great relevance. Nowadays, Global Asynchronous Local Synchronous Systems enables to use a Local Dynamic Voltage Scaling architecture, this technique allows achieve a high energy efficiency. Moreover, Local Dynamic Voltage Scaling can be implemented using different approaches. One of them is Vdd-Hopping technique. In this paper, different controllers are designed for a Vdd-Hopping system implemented in a novel discrete converter in order to search for control strategies that present better performance in terms of dissipated energy reduction. It is shown here that some of the provided control strategies not only reduce the dissipated energy, but also improves the current transients are improved

Hybrid dynamical control based on consensus algorithm for current sharing in DC-bus microgrids

The main objective of this work is to propose a novel paradigm for the design of two layers of control laws for DC-bus microgrids in islanded mode. An intensive attention will be paid to the inner control level for the regulation of DC-DC electronic power converters, where the use of Hybrid Dynamical System theory will be crucial to formulate and exploit switching control signals in view of reducing the dissipated energy and improving system performance. Indeed, this recent theory is well suited for analysis of power electronic converters, since they combine continuous (voltage and currents) and discrete (on-off state of switches) signals avoiding, in this way, the use of averaged models. Likewise, an outer control level for controlling DC-bus microgrids will be developed to provide a distributed strategy that makes the microgrid scalable and robust with respect to blackouts of sources and/or loads, following the principle of t Multi-Agent System theory. In this distributed strategy, they are several crucial and innovative aspects to be regarded such as the different converter architectures, the hybrid and nonlinear nature of these converters. Stability properties are guaranteed by using singular perturbation analysis

Conception de commandes pour des convertisseurs électroniques de puissance

A lot of research has recently been focused on converters due to the increasing deal of interest in power electronics. This is mainly caused by their broad applicability domain that includes battery-operating portable equipment, computers, appliances, vehicles, industrial electronic equipment, uninterruptible power supplies, telecommunication systems and much more. This current research is specially focused on finding highly-efficient converter topologies for every system application and, on designing control mechanisms that accomplishes the converter objectives. Among all variety of converters, this thesis is focused on providing a control solution for two converters topologies, which have some interesting properties and applications. The converters that will be dealt with are: firstly, a switch inverter topology; and secondly, a DC-DC converter for low power application. The first application is focused on controlling an SMPC boost inverter. This converter is particularly interesting because it does not only allow generating an alternating current, but it can also obtain an output voltage larger than the input signal. It has a high efficiency due to its switching character. Nevertheless, it has a non-minimum phase, 4th-order model. In addition, the desired behavior is not an equilibrium point but a limit cycle. Due to all the mentioned boost inverter characteristics, the main objective is to design a control law that guarantees not only the convergence to the desired limit cycle, but also the stability of it, with the particularity that no external reference is applied to the system. Likewise, the system has to accomplish right performance not only for known loads, but also for unknown loads. Another important aim is to estimate a set of initial voltage and current values, for which the system variables tend to the desired limit cycles when the control law before is applied to the boost inverter. If all these objectives are achieved, a control system guarantees a stable and robust behavior from an initial condition, which is within an estimated attraction region. And, in addition, the system is autonomous in the sense that no reference signals are needed. The second application deals with the control of a discrete DC-DC Vdd-Hooping converter. This is a low-power converter with a high-efficiency. Furthermore, it has suitable properties, for instance, it is a 1st-order model and its control objective is an equilibrium. Nevertheless, in low-power technology, this low level of efficiency may not become enough if certain requirements are demanded (e.g. high energy-efficiency, small current peaks, fats transient-times and reduced space). For this, to design a control law focused on achieving an optimal energy-efficiency may be an attractive problem. Indeed, the control problem of the Vdd-Hopping converter in this thesis comes directly demanded by the industry. Concretely, it is included in a French national project called ARAVIS, sponsored by the global competitive cluster Minalogic. The main objective of this converter is to guarantee that the system reaches the desired equilibrium point, achieving certain required features as: high-efficiency, stability, low computational cost, robustness with respect to parameter uncertainties and robustness with respect to delays due to synchronization and computation issues. In this way, the control law must be designed taken these objectives into account.Les convertisseurs électroniques font actuellement l'objet d'intensives recherches en raison de l'intérêt grandissant pour l'électronique de puissance. Ceci est principalement dû au grand nombre d'applications dans lesquelles ils apparaissent, comme, par exemple, dans les ordinateurs et téléphones portables, les véhicules, les équipements électroniques industriels, les grands systèmes de communication et bien plus encore. Ces investigations portent particulièrement deux points. Le premier concerne la recherche de topologies de convertisseurs dédiées à chaque application. Le second point traite de la conception de mécanismes de contrôle assurant que les objectifs de conversion sont satisfaits. Ma thèse se concentre sur l'élaboration des solutions de contrôle pour deux types de convertisseurs, qui ont des propriétés et des applications intéressantes. Les convertisseurs considérés sont, premièrement, un inverseur type « boost », et ensuite, un convertisseur « DC-DC VddHopping » pour les applications de faible puissance. Dans le premier cas, l'inverseur type boost, l'objectif de contrôle peut être vu comme la génération d'un cycle limite stable. Ce cycle limite est défini par une amplitude et une fréquence données. Les tensions de sortie des deux parties du système présentent, pour cette fréquence, un comportement sinusoïdal avec un changement de phase pré-spécifié. De plus, la loi de commande doit inclure des propriétés de robustesse par rapport à un certain nombre de contraintes. Par exemple, nous considérerons le cas de charges connues mais aussi inconnues. Un autre objectif important est de déterminer un ensemble de valeurs initiales de voltage et de courants, pour lesquelles les variables du système tendent vers leurs équilibres lorsque la loi de commande est appliquée à l'investisseur « boost». La deuxième partie de la thèse met l'accent sur le contrôle du convertisseur Vdd-Hopping DC-DC, consacré à des technologies de faible puissance. Ce travail se situe dans le cadre du projet national français appelé ARAVIS, parrainé par le pôle de compétitivité international Minalogic. Bien que ce soit aussi un convertisseur, la structure et la dynamique de ce système ainsi que les objectifs de contrôle sont radicalement différents du précédent. Ici il s'agit d'un système non linéaire du premier ordre. La sortie doit atteindre une valeur constante désirée et certaines requêtes exigées pour des systèmes de faible puissance doivent être satisfaites, telles qu'une haute efficacité, la stabilité de l'équilibre, la robustesse de l'équilibre incluant des retards et des incertitudes sur les paramètres, des phases transitoires rapides, la fiabilité, etc..

Hybrid dynamical control based on consensus algorithm for current sharing in DC-bus microgrids

International audienceThe main objective of this work is to propose a novel paradigm for the design of two layers of control laws for DC-bus microgrids in islanded mode. An intensive attention will be paid to the inner control level for the regulation of DC-DC electronic power converters, where the use of Hybrid Dynamical System theory will be crucial to formulate and exploit switching control signals in view of reducing the dissipated energy and improving system performance. Indeed, this recent theory is well suited for analysis of power electronic converters, since they combine continuous (voltage and currents) and discrete (on-off state of switches) signals avoiding, in this way, the use of averaged models. Likewise, an outer control level for controlling DC-bus microgrids will be developed to provide a distributed strategy that makes the microgrid scalable and robust with respect to blackouts of sources and/or loads, following the principle of t Multi-Agent System theory. In this distributed strategy, they are several crucial and innovative aspects to be regarded such as the different converter architectures, the hybrid and nonlinear nature of these converters. Stability properties are guaranteed by using singular perturbation analysis

Control Design for Electronic Power Converters

A lot of research has recently been focused on converters due to the increasing deal of interest in power electronics. This is mainly caused by their broad applicability domain that includes battery-operating portable equipment, computers, appliances, vehicles, industrial electronic equipment, uninterruptible power supplies, telecommunication systems and much more. This current research is specially focused on finding highly-efficient converter topologies for every system application and, on designing control mechanisms that accomplishes the converter objectives. Among all variety of converters, this thesis is focused on providing a control solution for two converters topologies, which have some interesting properties and applications. The converters that will be dealt with are: firstly, a switch inverter topology; and secondly, a DC-DC converter for low power application. The first application is focused on controlling an SMPC boost inverter. This converter is particularly interesting because it does not only allow generating an alternating current, but it can also obtain an output voltage larger than the input signal. It has a high efficiency due to its switching character. Nevertheless, it has a non-minimum phase, 4th-order model. In addition, the desired behavior is not an equilibrium point but a limit cycle. Due to all the mentioned boost inverter characteristics, the main objective is to design a control law that guarantees not only the convergence to the desired limit cycle, but also the stability of it, with the particularity that no external reference is applied to the system. Likewise, the system has to accomplish right performance not only for known loads, but also for unknown loads. Another important aim is to estimate a set of initial voltage and current values, for which the system variables tend to the desired limit cycles when the control law before is applied to the boost inverter. If all these objectives are achieved, a control system guarantees a stable and robust behavior from an initial condition, which is within an estimated attraction region. And, in addition, the system is autonomous in the sense that no reference signals are needed. The second application deals with the control of a discrete DC-DC Vdd-Hooping converter. This is a low-power converter with a high-efficiency. Furthermore, it has suitable properties, for instance, it is a 1st-order model and its control objective is an equilibrium. Nevertheless, in low-power technology, this low level of efficiency may not become enough if certain requirements are demanded (e.g. high energy-efficiency, small current peaks, fats transient-times and reduced space). For this, to design a control law focused on achieving an optimal energy-efficiency may be an attractive problem. Indeed, the control problem of the Vdd-Hopping converter in this thesis comes directly demanded by the industry. Concretely, it is included in a French national project called ARAVIS, sponsored by the global competitive cluster Minalogic. The main objective of this converter is to guarantee that the system reaches the desired equilibrium point, achieving certain required features as: high-efficiency, stability, low computational cost, robustness with respect to parameter uncertainties and robustness with respect to delays due to synchronization and computation issues. In this way, the control law must be designed taken these objectives into account.Les convertisseurs électroniques font actuellement l'objet d'intensives recherches en raison de l'intérêt grandissant pour l'électronique de puissance. Ceci est principalement dû au grand nombre d'applications dans lesquelles ils apparaissent, comme, par exemple, dans les ordinateurs et téléphones portables, les véhicules, les équipements électroniques industriels, les grands systèmes de communication et bien plus encore. Ces investigations portent particulièrement deux points. Le premier concerne la recherche de topologies de convertisseurs dédiées à chaque application. Le second point traite de la conception de mécanismes de contrôle assurant que les objectifs de conversion sont satisfaits. Ma thèse se concentre sur l'élaboration des solutions de contrôle pour deux types de convertisseurs, qui ont des propriétés et des applications intéressantes. Les convertisseurs considérés sont, premièrement, un inverseur type « boost », et ensuite, un convertisseur « DC-DC VddHopping » pour les applications de faible puissance. Dans le premier cas, l'inverseur type boost, l'objectif de contrôle peut être vu comme la génération d'un cycle limite stable. Ce cycle limite est défini par une amplitude et une fréquence données. Les tensions de sortie des deux parties du système présentent, pour cette fréquence, un comportement sinusoïdal avec un changement de phase pré-spécifié. De plus, la loi de commande doit inclure des propriétés de robustesse par rapport à un certain nombre de contraintes. Par exemple, nous considérerons le cas de charges connues mais aussi inconnues. Un autre objectif important est de déterminer un ensemble de valeurs initiales de voltage et de courants, pour lesquelles les variables du système tendent vers leurs équilibres lorsque la loi de commande est appliquée à l'investisseur « boost». La deuxième partie de la thèse met l'accent sur le contrôle du convertisseur Vdd-Hopping DC-DC, consacré à des technologies de faible puissance. Ce travail se situe dans le cadre du projet national français appelé ARAVIS, parrainé par le pôle de compétitivité international Minalogic. Bien que ce soit aussi un convertisseur, la structure et la dynamique de ce système ainsi que les objectifs de contrôle sont radicalement différents du précédent. Ici il s'agit d'un système non linéaire du premier ordre. La sortie doit atteindre une valeur constante désirée et certaines requêtes exigées pour des systèmes de faible puissance doivent être satisfaites, telles qu'une haute efficacité, la stabilité de l'équilibre, la robustesse de l'équilibre incluant des retards et des incertitudes sur les paramètres, des phases transitoires rapides, la fiabilité, etc..

Time-triggered and event-triggered control of switched affine systems via a hybrid dynamical approach

This paper focuses on the design of both periodic time-and event-triggered control laws of switched affine systems using a hybrid dynamical system approach. The novelties of this paper rely on the hybrid dynamical representation of this class of systems and on a free-matrix min-projection control, which relaxes the structure of the usual Lyapunov matrix-based min-projection control. This contribution also presents an extension of the usual periodic time-triggered case to the event-triggered one, where the control updates are permitted only when a particular event is detected. Together with the definition of an appropriate optimization problem, a stabilization result is formulated to ensure the uniform global asymptotic stability of an attractor for both types of controllers, which is a neighborhood of the desired equilibrium. Finally, the proposed method is evaluated through a numerical example

Control del convertidor boost DC-AC por moldeo de energía

National audienceEn este artículo se aplica a un convertidor boost dc-ac no lineal una estrategia de control para la generación de corriente alterna sin emplear señal de referencia alguna. Como la técnica propuesta no alcanza la sincronización deseada entre las dos partes del circuito, se añade un Phase-Locked Loop a la ley de control. Se muestra además que esta idea es válida para la sincronización con la red. Mediante simulación se comprueba la bondad de las leyes de control resultantes

Time-triggered and event-triggered control of switched affine systems via a hybrid dynamical approach

This paper focuses on the design of both periodic time-and event-triggered control laws of switched affine systems using a hybrid dynamical system approach. The novelties of this paper rely on the hybrid dynamical representation of this class of systems and on a free-matrix min-projection control, which relaxes the structure of the usual Lyapunov matrix-based min-projection control. This contribution also presents an extension of the usual periodic time-triggered case to the event-triggered one, where the control updates are permitted only when a particular event is detected. Together with the definition of an appropriate optimization problem, a stabilization result is formulated to ensure the uniform global asymptotic stability of an attractor for both types of controllers, which is a neighborhood of the desired equilibrium. Finally, the proposed method is evaluated through a numerical example