Santiago de Pablo

Hexagon based algorithm for Space Vector Modulation on multilevel voltage source inverters

A simple algorithm has been developed to control small and large multilevel inverters using Space Vector Modulation. It looks for a suitable hexagon near the reference voltage rather than the usual three nearest vectors. Then, switching vectors and their duty cycles are computed using straightforward equations, independent of the number of levels and easy to use in digital microprocessors. Several simulations have validated this method, finding that these duty cycles are exactly the same than others, computed using more complex methods.

Using PBL to Improve Educational Outcomes and Student Satisfaction in the Teaching of DC/DC and DC/AC Converters

This paper examines the question of how to use project-based learning to increase student performance and satisfaction in a power electronics course addressing the topics of dc/dc and dc/ac converters, the assembly of a dc/dc converter, and the use of a commercial speed drive. A detailed presentation of the methodology is shown, and the results are analyzed by comparison to previous academic years and by satisfaction surveys. The new course design applies the jigsaw cooperative learning strategy to have students learn the theory of converters, solve problems, and perform simulations, before carrying out projects that solve real-world problems, such as the power converter for a competition solar vehicle (2014/15 course) and power converters for an air conditioner with inverter technology (2015/16 course). Rubrics were used to evaluate the students’ work reports and the simulations. The project deliverables are presented and assessed in two design reviews, the first version covering the design and an open loop simulation, and the second covering the closed loop simulation and verification of specifications.This paper examines the question of how to use project-based learning to increase student performance and satisfaction in a power electronics course addressing the topics of dc/dc and dc/ac converters, the assembly of a dc/dc converter, and the use of a commercial speed drive. A detailed presentation of the methodology is shown, and the results are analyzed by comparison to previous academic years and by satisfaction surveys. The new course design applies the jigsaw cooperative learning strategy to have students learn the theory of converters, solve problems, and perform simulations, before carrying out projects that solve real-world problems, such as the power converter for a competition solar vehicle (2014/15 course) and power converters for an air conditioner with inverter technology (2015/16 course). Rubrics were used to evaluate the students’ work reports and the simulations. The project deliverables are presented and assessed in two design reviews, the first version covering the design and an open loop simulation, and the second covering the closed loop simulation and verification of specifications.

Emulador de Lazo Abierto para Turbinas Eólicas de Paso Fijo

A novel emulator for fixed pitch wind turbines that allows laboratory testing of the generator control systems associated with the turbines is presented. The novelty of the emulator is to be an open loop scheme. The emulator consists of the coupling in series of a source of DC voltage, a power resistance and a DC motor. The modification of the input DC voltage has the same effect as the variation of wind speed in a fixed pitch wind turbine. This article includes: 1) theoretical foundations of the emulator, 2) Excel and Simulink simulations, and 3) experimental results obtained in a bench of electrical machines. It is shown that the emulator can reproduce the mechanical power curves of a fixed pitch turbine, but with certain limitations at low speed.

Diseño de Circuitos Digitales a Nivel de Registro empleando Diagramas ASM

Este articulo muestra la estrecha relacion que existe entre los diagramas de estado algoritmicos (ASM charts) y los modernos lenguajes de descripcion de circuitos, ambos empleados en el diseno de circuitos digitales. Se proponen sustanciales mejoras sobre la notacion actual con el objetivo de desarrollar un compilador capaz de procesar automaticamente estos diagramas y generar el codigo VHDL o Verilog correspondiente. El uso de esta metodologia facilita el aprendizaje del diseno de circuitos digitales a nivel de transferencia entre registros (RTL). El lenguaje grafico propuesto es facil de aprender y es entendido sin dificultad por estudiantes universitarios, quienes lo emplean como parte de la metodologia de diseno para producir circuitos digitales sobre dispositivos reconfigurables tipo FPGA y CPLD.

STATCOM Control Strategies

This chapter reviews the control systems used to enable STATCOMs to carry out their most important task, which is to deliver reactive power to the electrical grid. Later on, other control systems designed for more advanced applications are discussed, such as compensating the nonlinear loads. Later, the design of the control system when STATCOMs are connected to unbalanced electrical networks is presented. Several strategies are presented for controlling the converter, either as a linear current source which is also known as controlled Voltage Source Converter (VSC) based on the use of Proportional-Integral (PI) controllers, or as nonlinear current source, based on the use of hysteresis bands. Other systems, such as the firing algorithm of the switches or system synchronization with the grid, are also discussed.

Encapsulating connections on SoC designs using ASM++ charts

This article presents a methodology to encapsulate, not only the functionality of several SoC modules, but also the connections between those modules. To achieve these results, the possibilities of Algorithmic State Machines (ASM charts) have been extended to develop a compiler. Using this approach, a SoC design becomes a set of chart boxes and links: several boxes describe parameterized modules in a hierarchical fashion, other boxes encapsulate their connections, and all boxes are linked together using simple lines. At last, a compiler processes all required files and generates the corresponding VHDL or Verilog code, valid for simulation and synthesis. A small SoC design with two DSP processors is shown as an example.