Sliding-Mode Control Design of a Boost-Buck Switching Converter for AC Signal Generation

This paper presents a sliding-mode control design of a boost–buck switching converter for a voltage step-up dc–ac conversion without the use of any transformer. This approach combines the step-up/step-down conversion ratio capability of the converter with the robustness properties of sliding-mode control. The proposed control strategy is based on the design of two slidingcontrol laws, one ensuring the control of a full-bridge buck converter for proper dc–ac conversion, and the other one the control a boost converter for guaranteeing a global dc-to-ac voltage step-up ratio. A set of design criteria and a complete design procedure of the sliding-control laws are derived from small-signal analysis and large-signal considerations. The experimental results presented in the paper evidence both the achievement of step-up dc–ac conversion with good accuracy and robustness in front of input voltage and load perturbations, thus validating the proposed approach.Peer Reviewe

One-Quadrant Switched-Mode Power Converters

This article presents the main topics related to one-quadrant power converters. The basic topologies are analysed and a simple methodology to obtain the steady-state output-input voltage ratio is set out. A short discussion of different methods to control one-quadrant power converters is presented. Some of the reported derived topologies of one-quadrant power converters are also considered. Some topics related to one-quadrant power converters such as synchronous rectification, hard and soft commutation, and interleaved converters are discussed. Finally, a brief introduction to resonant converters is given.Comment: 25 pages, contribution to the 2014 CAS - CERN Accelerator School: Power Converters, Baden, Switzerland, 7-14 May 201

Advances in Control of Power Electronic Converters

This book proposes a list of contributions in the field of control of power electronics converters for different topologies: DC-DC, DC-AC and AC-DC. It particularly focuses on the use of different advanced control techniques with the aim of improving the performances, flexibility and efficiency in the context of several operation conditions. Sliding mode control, fuzzy logic based control, dead time compensation and optimal linear control are among the techniques developed in the special issue. Simulation and experimental results are provided by the authors to validate the proposed control strategies

Design and Control of Power Converters 2019

In this book, 20 papers focused on different fields of power electronics are gathered. Approximately half of the papers are focused on different control issues and techniques, ranging from the computer-aided design of digital compensators to more specific approaches such as fuzzy or sliding control techniques. The rest of the papers are focused on the design of novel topologies. The fields in which these controls and topologies are applied are varied: MMCs, photovoltaic systems, supercapacitors and traction systems, LEDs, wireless power transfer, etc

Global Tracking Passivity--based PI Control of Bilinear Systems and its Application to the Boost and Modular Multilevel Converters

This paper deals with the problem of trajectory tracking of a class of bilinear systems with time--varying measurable disturbance. A set of matrices {A,B_i} has been identified, via a linear matrix inequality, for which it is possible to ensure global tracking of (admissible, differentiable) trajectories with a simple linear time--varying PI controller. Instrumental to establish the result is the construction of an output signal with respect to which the incremental model is passive. The result is applied to the boost and the modular multilevel converter for which experimental results are given.Comment: 9 pages, 10 figure

Fixed-switching frequency sliding mode control applied to power converters

The application of the sliding mode control in power converters has a well-known inconvenient from the practical point of view, which is to obtain fixed switching frequency implementations. This thesis deals with the development of a hysteresis band controller in charge of fixing the switching frequency of a sliding motion in power electronics applications. The proposed control measures the switching period of the control signal and modifies the hysteresis band of the comparator in order to regulate the switching frequency of the sliding motion. The proposed structure becomes in an additional control loop aside from main control loop implementing the sliding mode controller. In the first part of the thesis, the switching frequency control system is modelled and a design criteria for the control parameters are derived for guaranteeing closed loop stability, under different approaches and taking into account the most expectable working scenarios. In the second part of the thesis, the proposed strategies are applied to several power converters prototypes. Specifically, DC-to-DC and DC-to-AC power converters are built and the experimental results are shown. In this part, the strategies used for implementing the controllers are also deeply discussed.La aplicación del control en modo deslizante en el ámbito de la electrónica de potencia presente una problemática ampliamente conocida, obtener aplicaciones a frecuencia fija de operación. Es esta tesis se estudia el desarrollo de un comparador con histéresis variable encargado de regular el periodo de conmutación de controladores bajo regímenes deslizantes en convertidores de potencia. La estructura propuesta mide el periodo de conmutación de la señal de control y actualiza, de manera adecuada, la banda de histéresis del comparador a tal fin de regular la frecuencia de conmutación al valor deseado. La solución propuesta forma un segundo lazo de control, además del lazo de control principal que implementa el controlador en modo deslizante. En la primera parte de la tesis, éste segundo lazo es modelado, haciendo posible el estudio de las condiciones de estabilidad bajo realizaciones en tiempo continuo y en tiempo discreto. Además, se estudian las condiciones típicas de trabajo de los controladores utilizados en convertidores de potencia, como son los esquemas de regulación y de seguimiento de señales variantes en el tiempo. La segunda parte de la tesis se centra en evaluar, de manera experimental, los desarrollos teóricos de los controladores propuestos en convertidores de potencia. Concretamente, en la tesis se presentan los resultados experimentales obtenidos con diversos convertidores DC-DC y DC-AC. Adicionalmente, las metodologías y técnicas de implementación de los controladores son, de igual modo, ampliamente descritas.Postprint (published version

Fixed-switching frequency sliding mode control applied to power converters

The application of the sliding mode control in power converters has a well-known inconvenient from the practical point of view, which is to obtain fixed switching frequency implementations. This thesis deals with the development of a hysteresis band controller in charge of fixing the switching frequency of a sliding motion in power electronics applications. The proposed control measures the switching period of the control signal and modifies the hysteresis band of the comparator in order to regulate the switching frequency of the sliding motion. The proposed structure becomes in an additional control loop aside from main control loop implementing the sliding mode controller. In the first part of the thesis, the switching frequency control system is modelled and a design criteria for the control parameters are derived for guaranteeing closed loop stability, under different approaches and taking into account the most expectable working scenarios. In the second part of the thesis, the proposed strategies are applied to several power converters prototypes. Specifically, DC-to-DC and DC-to-AC power converters are built and the experimental results are shown. In this part, the strategies used for implementing the controllers are also deeply discussed.La aplicación del control en modo deslizante en el ámbito de la electrónica de potencia presente una problemática ampliamente conocida, obtener aplicaciones a frecuencia fija de operación. Es esta tesis se estudia el desarrollo de un comparador con histéresis variable encargado de regular el periodo de conmutación de controladores bajo regímenes deslizantes en convertidores de potencia. La estructura propuesta mide el periodo de conmutación de la señal de control y actualiza, de manera adecuada, la banda de histéresis del comparador a tal fin de regular la frecuencia de conmutación al valor deseado. La solución propuesta forma un segundo lazo de control, además del lazo de control principal que implementa el controlador en modo deslizante. En la primera parte de la tesis, éste segundo lazo es modelado, haciendo posible el estudio de las condiciones de estabilidad bajo realizaciones en tiempo continuo y en tiempo discreto. Además, se estudian las condiciones típicas de trabajo de los controladores utilizados en convertidores de potencia, como son los esquemas de regulación y de seguimiento de señales variantes en el tiempo. La segunda parte de la tesis se centra en evaluar, de manera experimental, los desarrollos teóricos de los controladores propuestos en convertidores de potencia. Concretamente, en la tesis se presentan los resultados experimentales obtenidos con diversos convertidores DC-DC y DC-AC. Adicionalmente, las metodologías y técnicas de implementación de los controladores son, de igual modo, ampliamente descritas

Control Strategies of DC–DC Converter in Fuel Cell Electric Vehicle

There is a significant need to research and develop a compatible controller for the DC–DC converter used in fuel cells electric vehicles (EVs). Research has shown that fuel cells (FC) EVs have the potential of providing a far more promising performance in comparison to conventional combustion engine vehicles. This study aims to present a universal sliding mode control (SMC) technique to control the DC bus voltage under varying load conditions. Additionally, this research will utilize improved DC–DC converter topologies to boost the output voltage of the FCs. A DC–DC converter with a properly incorporated control scheme can be utilized to regulate the DC bus voltage–. A conventional linear controller, like a PID controller, is not suitable to be used as a controller to regulate the output voltage in the proposed application. This is due to the nonlinearity of the converter. Furthermore, this thesis will explore the use of a secondary power source which will be utilized during the start–up and transient condition of the FCEV. However, in this instance, a simple boost converter can be used as a reference to step–up the fuel cell output voltage. In terms of application, an FCEV requires stepping –up of the voltage through the use of a high power DC–DC converter or chopper. A control scheme must be developed to adjust the DC bus or load voltage to meet the vehicle requirements as well as to improve the overall efficiency of the FCEV. A simple SMC structure can be utilized to handle these issues and stabilize the output voltage of the DC–DC converter to maintain and establish a constant DC–link voltage during the load variations. To address the aforementioned issues, this thesis presents a sliding mode control technique to control the DC bus voltage under varying load conditions using improved DC–DC converter topologies to boost and stabilize the output voltage of the FCs

A Robust Consensus Algorithm for Current Sharing and Voltage Regulation in DC Microgrids

In this paper a novel distributed control algorithm for current sharing and voltage regulation in Direct Current (DC) microgrids is proposed. The DC microgrid is composed of several Distributed Generation units (DGUs), including Buck converters and current loads. The considered model permits an arbitrary network topology and is affected by unknown load demand and modelling uncertainties. The proposed control strategy exploits a communication network to achieve proportional current sharing using a consensus-like algorithm. Voltage regulation is achieved by constraining the system to a suitable manifold. Two robust control strategies of Sliding Mode (SM) type are developed to reach the desired manifold in a finite time. The proposed control scheme is formally analyzed, proving the achievement of proportional current sharing, while guaranteeing that the weighted average voltage of the microgrid is identical to the weighted average of the voltage references.Comment: 12 page