5 research outputs found
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...IngenierÃa 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 fÃsicos que posee la planta y sus
caracterÃsticas. 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 asà una tabla con las todas las funciones de transferencia obtenidas en Modo de conducción continua y en modo de
conducción discontinua.IngenierÃa Técnica en Electrónic
Investigation of output filter topologies for a Parallel Hybrid Converter based on Si-IGBTs and partially-rated SiC-MOSFETs
Converter Topology for Megawatt Scale Applications with Reduced Filtering Requirements, formed of IGBT Bridge operating in the 1000 Hz Region with Parallel Part-Rated High-Frequency SiC MOSFET Bridge
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