Endochrony of distributed systems

Through the years the embedded system technologies have been developing and evolving, leading to very complex systems. Due to the complexity of the embedded system and hardware design, the designer split up the complex system into smaller systems. This is one of the reasons that we nowadays have a great number of distributed systems. Therefore, instead of having a larger design which requires time consuming simulation and verification, the new design divides the complex system into simpler systems. The simpler systems are called components in order to differentiate from the complex system. The advantage of those systems is that as they can be placed in different locations, they can run independently from each other. The other advantage of working in an asynchronous environment of the distributed system is that all the components do not have to wait for the . To understand the term , it is necessary to compare the two kinds of distributed systems in the network depending on the computation model: the synchronous system and the asynchronous system. The synchronous system is controlled by a unique global clock and the global clock is constrained by the slowest component. All the others components of the system must wait to make the communication to an external environment as well as other components, until the slowest component ends its activity. After all the components have finished their activity, the whole system can interact at one point of time to the others components and to the external environment. On the other hand, we have the asynchronous system where every component runs independently without controlled by a global clock. Then, each component communicates with the environment or the other components at different points of time...Ingeniería Técnica en Electrónic

Modelado y diseño del control del convertidor reductor-elevador en modo corriente de pico

Los convertidores DC-DC tienen numerosas aplicaciones tanto a nivel de fábrica como a nivel usuario, además de ello se caracterizan por tener un bajo coste económico, lo cual les hace atractivos desde el punto de vista del cliente. Este estudio se ha llevado a cabo durante muchos años, el objetivo que persigue este proyecto es ser capaz de regular la estabilidad de tensión de salida, es decir, eficientemente y en un tiempo reducido, incluso ante inevitables perturbaciones o errores. Estas perturbaciones pueden ser caudadas por un medio externo como la tensión de alimentación y tipo de carga, y por el medio interno que no son más que los elementos del convertidor DC/DC. Consecuentemente con lo anterior se persigue realizar un análisis de sensibilidad de los parámetros de la planta, los efectos físicos que posee la planta y sus características. En cuanto al modelado del modulador, no presenta problema alguno hasta que el ciclo de trabajo sea D>0.5, a partir de este valor el sistema se desestabiliza ante cualquier perturbación. Ante este problema se ve en la medida de añadir un nuevo circuito de control que se denomina Rampa de Compensación. Asimismo hay que tener en cuenta que el modulador por corriente de pico depende de muchas variables que se contará más adelante. Según el modelado dinámico elegido, al unir los modelados de la planta y el modulador, se obtiene unas funciones de transferencia canónicas genéricas para cualquier tipo de convertidor DC/DC, esta información proporcionada un nuevo dato que permitirá al usuario acceder de forma abierta y automatizada a las funciones de transferencia requeridas. Además se añade el estudio de una nueva variable de perturbación: la corriente de carga io , este parámetro se suma con las perturbaciones de la fuente de alimentación vg y la corriente de control c i para dar resultado a un mejor estudio dinámico en pequeña señal que se aproxime al resultado experimental. Las funciones de transferencia genéricas son 3 ecuaciones matemáticas en Laplace que van a realizar el estudio del comportamiento dinámico de la tensión de salida después de haber perturbado las variables de entrada del sistema. Estas funciones teóricas se plasman en Mathcad, programa algebraico de ordenador, el cual brinda el bode que se compara para su validación con las simulaciones realizadas en Psim, programa de simulación de circuitos analógicos. Por último, se pretende brindar un diseño automático del control en modo corriente de pico para el convertidor Reductor-Elevador brindando así una tabla con las todas las funciones de transferencia obtenidas en Modo de conducción continua y en modo de conducción discontinua.Ingeniería Técnica en Electrónic

Finite-set MPC enabled hybrid power converters comprised of Si/SiC power modules

This thesis presents a hybrid grid-tied converter, composed of a slow-switching frequency, fully rated Silicon (Si)-Insulated-gate bipolar transistor (IGBT) based inverter complimented with a part-rated high-switching frequency auxiliary inverter based on Silicon Carbide (SiC)-Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET)s. The SiC-MOSFET converter behaves as an active filter compensating the current harmonics levels caused by the Si-IGBT converter. The synergy between both devices at the converter level along with the control strategy aims to: provide a higher power quality, improve the system efficiency, shrink passive filters and enhance the controller bandwidth. Effective operation of the hybrid converter requires that the IGBT switching frequency is minimised whilst limiting the current in the SiC-MOSFET inverter. Achieving this balance while maintaining control over the total output current was enabled by the development of a Finite Control Set Model Predictive Control (FCS-MPC) controller. Two potential variants on of the hybrid converter were studied, each with its respective control strategy. The topologies are: parallel hybrid converter and shunt hybrid converter. These were evaluated by using simulations and the results benchmarked using a laboratory demonstrator. Experimental results required the design and construction of a 90 kW test bench, which combined 1.2kV Si-IGBT and SiC-MOFET inverter modules in a hybrid configuration. The test bench consists of rectifier and the hybrid converter placed in independent cabinets and is designed to recirculate power with the three phase AC supply. The hybrid converter cabinet contains the 400A IGBT and of 300A SiC-MOSFET inverters together with their auxiliary electronics, measurement devices and passive components. Control of both converters is implemented using the FPGA of a dSPACE platform. Safety implementations were since early stage considered. Results obtained from the experimental hardware showed good agreement with simulation results and demonstrated the capability of the hybrid converter to control output current whilst minimising switching loss in the IGBT converter. These results validated the concept of the FCS-MPC for hybrid converters and provide confidence that the concept could be extended to MW applications