Sistema embebido para el control de carga de baterías en un vehículo eléctrico híbrido ligero (EPISOL)

El presente trabajo es resultado de un proyecto para desarrollar un vehículo híbrido con varias fuentes de carga de baterías. Su objetivo es contribuir a reducir las emisiones debidas al tráfico urbano de vehículos, tendencia muy buscada en los últimos años, donde se han acometido importantes proyectos de investigación orientados al desarrollo de sistemas de propulsión y combustibles alternativos a los actualmente mayoritarios. A continuación se describe el sistema embebido de control realizado, en el que un microcontrolador se encarga del ajuste de la carga de las baterías, a partir de las contribuciones de una pila de combustible, unos paneles solares y un generador conectado a un motor de combustión interna, para conseguir el mayor rendimiento energético y lograr unos niveles de emisiones casi nulos

A Reconfigurable Buck, Boost, and Buck-Boost Converter: Unified Model and Robust Controller

The need for reconfigurable, high power density, and low-cost configurations of DC-DC power electronic converters (PEC) in areas such as the transport electrification and the use of renewable energy has spread out the requirement to incorporate in a single circuit several topologies, which generally result in an increment of complexity about the modeling, control, and stability analyses. In this paper, a reconfigurable topology is presented which can be applied in alterative/changing power conversion scenarios and consists of a reconfigurable Buck, Boost, and Buck-Boost DC-DC converter (RBBC). A unified averaged model of the RBBC is obtained, a robust controller is designed through a polytopic representation, and a Lyapunov based switched stability analysis of the closed-loop system is presented. The reported RBBC provides a wide range of voltage operation, theoretically from -∞ to ∞ volts with a single power source. Robust stability, even under arbitrarily fast (bounded) parameter variations and reconfiguration changes, is reported including numerical and experimental results. The main advantages of the converter and the robust controller proposed are simple design, robustness against abrupt changes in the parameters, and low cost

Резонантен преобразувач за индукционо загревање на метали со подобрување на коефициентот на полезно дејство

Во докторската дисертација, врз база на теориска анализа, е развиен нов метод за управување на мостен сериски резонантен конвертор во режим на работа над резонантната фреквенција и во услови на вклучување на прекинувачите при ZCS и ZVS. Методот користи директно управување на фазната разлика меѓу излезните напон и струја, а за него е развиен алгоритам за дигитална имплементација. Развиениот метод базира врз коло за управување кое го следи фазниот агол φ, меѓу напонот и струјата на резонантното коло, преку мерење на неговиот временски еквивалент tφ. Врз основа на измереното tφ колото за управување врши нагодување на работната периода така што фазниот агол да биде еднаков на зададениот референтен фазен агол φref

Stabilizing Controller Design for a DC Power Distribution System Using A Passivity-Based Stability Criterion

In modern times there has been an increased penetration of power electronic converters into Power Distribution Systems. In particular, there has been a strong interest in DC Power Distribution Systems as opposed to conventional AC Power distribution systems. These DC Power Distribution Systems are enabled by power electronics converters. The strong interest is motivated by improvements in power electronic converter technology, like advances in power semiconductor devices, magnetics, control, and converter topologies which have made possible to build high-performance converters at low cost. In many systems, such as cars, ships and airplanes, there has also been a trend towards the replacement of a number of older mechanical and hydraulic systems with electrical power-electronic-based systems, since these systems provide a number of advantages such as increased system flexibility, reliability, long life expectancy and decreased weight, size, and cost. Together with these advantages, DC Power Distribution Systems offer system-level challenges related to system stability issues and design of individual converter controllers to guarantee proper operation of the interconnected system. System-level stability issues may arise due to interactions among feedback-controlled power converters, which are part of such a large interconnected system. These feedback-controlled power converters exhibit negative incremental input impedance within their control bandwidth. As a result, a power converter that was satisfactorily performing when tested as a standalone unit may experience degradation in performance when connected as part of a system. While the analysis and design of a single power converter and its controls is well understood, in a DC Power Distribution System the situation is different. Analyzing and designing a complex multi-converter system in such a way as to guarantee both system stability and performance is a complex problem that was not fully solved in the past. Difficulties stem from a lack of adequate analysis and design tools, limited understanding of the problem, difficulties in applying the existing stability criteria, and the need for stabilizing converter controllers. To tackle all these difficulties, the present work proposes two tools to address system level stability issues in DC Power Distribution Systems: the Passivity-Based Stability Criterion (PBSC) and the Positive Feed-Forward (PFF) control. The PBSC is proposed as a tool for stability analysis in a DC Power Distribution System. The criterion is based on imposing passivity of the overall DC bus impedance. If passivity of the bus impedance is ensured, stability is guaranteed as well. The PBSC, which imposes conditions on the overall bus impedance, offers several advantages with respect to existing stability criteria, such as the Middlebrook criterion and its extensions, which are based on the minor loop gain concept, i.e. an impedance ratio at a given interface: reduction of artificial design conservativeness, insensitivity to component grouping, applicability to multi-converter systems and to systems in which the power flow direction changes, for example as a result of system reconfiguration. Moreover, the criterion is very designed-oriented because it can be used in conjunction with the second tool proposed in this dissertation, the PFF control, for the design of stabilizing virtual damping networks. The PFF controller design formulation guarantees both stability and performance (a challenge not fully solved in the past, as previously stated). By designing the stabilizing virtual impedance so that the bus impedance passivity condition is met, the approach results in greatly improved stability and damping of transients on the DC bus voltage. Simulation validation is performed using a switching-level-model of the DC power distribution system. Experimental validation is carried out on a DC power distribution system built in the laboratory

Design and implementation of multi-port DC-DC converters for electrical power systems

The thesis proposes developing, analysing, and verifying these DC-DC converters to improve the current state-of-the-art topology. Four new DC-DC converters for applications like light emitting diode, lighting microgrids DC, PV applications, and electric vehicles are as follows. In this study, the two-input converter is presented. The two-input converter that has been proposed serves as the interface between the two input sources and load. Using two switches and two diodes, the proposed converter minimises switching losses and contains eight components in total, making it compact and low volume. As a result, the highest average efficiency is 92.5%, and the lowest is 89.6%. In this research, the new three-port converter that has been proposed serves as the interface between the input source, a battery, and a load. In addition, the converter is suitable for use in standalone systems or satellite applications. A low-volume converter is designed with three switches and two diodes, thereby minimizing switching losses and ten components in total. Regarding efficiency, the highest average is 92.5%, and the lowest is 90.9%. Also, this study proposes a single-switch high-step-up converter for LED drivers and PV applications. A further benefit of the proposed converter over conventional classical converters is that it utilises only one active switch. These results align with simulation results, and its gain is 6.8 times greater than classical converters. Furthermore, stress across switches and diodes is smaller than the output voltage, approximately 50%. Semiconductor losses were limited with a low duty cycle of 0.7. This makes the highest average efficiency 95% and the lowest 93.9%. The new four-port converter is presented for applications such as microgrid structures and electric vehicles. As part of the integrated converter, two or three converters are combined by sharing some components, such as switches, inductors, and capacitors, to form a single integrated converter. As a result of the four-port converter proposed, battery power can be managed, and output voltage can be regulated simultaneously