Ma.A.M. Prats

Bio: Ma.A.M. Prats is an academic researcher from University of Seville. The author has contributed to research in topics: Adaptive control & Direct torque control. The author has an hindex of 5, co-authored 5 publications receiving 3622 citations.

Power-Electronic Systems for the Grid Integration of Renewable Energy Sources: A Survey

Abstract: The use of distributed energy resources is increasingly being pursued as a supplement and an alternative to large conventional central power stations. The specification of a power-electronic interface is subject to requirements related not only to the renewable energy source itself but also to its effects on the power-system operation, especially where the intermittent energy source constitutes a significant part of the total system capacity. In this paper, new trends in power electronics for the integration of wind and photovoltaic (PV) power generators are presented. A review of the appropriate storage-system technology used for the integration of intermittent renewable energy sources is also introduced. Discussions about common and future trends in renewable energy systems based on reliability and maturity of each technology are presented

Three-dimensional space-vector modulation algorithm for four-leg multilevel converters using abc coordinates

Abstract: In this paper, a novel three-dimensional (3-D) space-vector algorithm for four-leg multilevel converters is presented. It can be applied to active power filters or neutral-current compensator applications for mitigating harmonics and zero-sequence components using abc coordinates (referred from now on this paper as natural coordinates). This technique greatly simplifies the selection of the 3-D region where a given voltage vector is supposed to be found. Compared to a three-level modulation algorithm for three-leg multilevel converters, this algorithm does not increase its complexity and the calculations of the active vectors with the corresponding switching time that generate the reference voltage vector. In addition, the low-computational cost of the proposed algorithm is always the same and it is independent of the number of levels of the converter.

A switching control strategy based on output regulation subspaces for the control of induction motors using a three-level inverter

Abstract: In this work we present the design of a new switching control strategy for a three-level converter aimed to improve the performance of a direct torque control (DTC) for induction machines, special attention is given to the reduction of torque ripple. As in classical DTC, the proposed technique is aimed to directly regulate the outputs: torque and flux amplitude. We show that classical DTC can be considered as a particular case of the proposed control strategy. The proposed criterion to design the switching control sequence is based on a quadratic criterion of the output errors plus a prediction in one-step ahead, and an interesting partition of the input state space generated by the output regulation subspaces (ORS) to facilitate the selection of the control vector for reducing the computational load. As a result, a control vector is selected without the requirement of an auxiliary space vector or any other modulation technique. Simulations results using the proposed control technique confirm the validity of this approach.

Control of a three level converter used as a synchronous rectifier

Abstract: We present an adaptive controller for a three level synchronous rectifier. The controller guarantees regulation and balance of the output capacitors voltages, as well as a close to unity power factor, simultaneously. The design is based on a model in /spl alpha//spl beta//spl gamma/-coordinates of the three level converter. Special attention is given to the /spl gamma/-component of the control input, since it has direct influence in the balancing of the capacitors voltages, represented here as the arithmetic difference of voltages. Moreover, it is shown that this difference is polluted by a periodic disturbance, which is also compensated by the proposed controller by adding an adaptive term to the control law. After some transformations, this adaptive term is finally reduced to a bank of resonant filters. Simulations results are presented to asses the performance of the proposed controller.

Three dimensional space vector modulation for four-leg inverters using natural coordinates

Abstract: Thanks to the use of natural coordinates (abc coordinates), the proposed modulation algorithm is much simpler and intuitive than using /spl alpha//spl beta//spl gamma/ representation, reducing the complexity of modulation algorithm and the computational load associated to it. The application chosen, the 4-wire 4-leg inverter, is employed only as an example of how easy the modulation results using this notation instead of classical /spl alpha//spl beta//spl gamma/ representation.

Power-Electronic Systems for the Grid Integration of Renewable Energy Sources: A Survey

Abstract: The use of distributed energy resources is increasingly being pursued as a supplement and an alternative to large conventional central power stations. The specification of a power-electronic interface is subject to requirements related not only to the renewable energy source itself but also to its effects on the power-system operation, especially where the intermittent energy source constitutes a significant part of the total system capacity. In this paper, new trends in power electronics for the integration of wind and photovoltaic (PV) power generators are presented. A review of the appropriate storage-system technology used for the integration of intermittent renewable energy sources is also introduced. Discussions about common and future trends in renewable energy systems based on reliability and maturity of each technology are presented

Recent Advances and Industrial Applications of Multilevel Converters

Abstract: Multilevel converters have been under research and development for more than three decades and have found successful industrial application. However, this is still a technology under development, and many new contributions and new commercial topologies have been reported in the last few years. The aim of this paper is to group and review these recent contributions, in order to establish the current state of the art and trends of the technology, to provide readers with a comprehensive and insightful review of where multilevel converter technology stands and is heading. This paper first presents a brief overview of well-established multilevel converters strongly oriented to their current state in industrial applications to then center the discussion on the new converters that have made their way into the industry. In addition, new promising topologies are discussed. Recent advances made in modulation and control of multilevel converters are also addressed. A great part of this paper is devoted to show nontraditional applications powered by multilevel converters and how multilevel converters are becoming an enabling technology in many industrial sectors. Finally, some future trends and challenges in the further development of this technology are discussed to motivate future contributions that address open problems and explore new possibilities.

Multilevel Voltage-Source-Converter Topologies for Industrial Medium-Voltage Drives

Abstract: This paper presents a technology review of voltage-source-converter topologies for industrial medium-voltage drives. In this highly active area, different converter topologies and circuits have found their application in the market. This paper covers the high-power voltage-source inverter and the most used multilevel-inverter topologies, including the neutral-point-clamped, cascaded H-bridge, and flying-capacitor converters. This paper presents the operating principle of each topology and a review of the most relevant modulation methods, focused mainly on those used by industry. In addition, the latest advances and future trends of the technology are discussed. It is concluded that the topology and modulation-method selection are closely related to each particular application, leaving a space on the market for all the different solutions, depending on their unique features and limitations like power or voltage level, dynamic performance, reliability, costs, and other technical specifications.

Synchronverters: Inverters That Mimic Synchronous Generators

Abstract: In this paper, the idea of operating an inverter to mimic a synchronous generator (SG) is motivated and developed. We call the inverters that are operated in this way synchronverters. Using synchronverters, the well-established theory/algorithms used to control SGs can still be used in power systems where a significant proportion of the generating capacity is inverter-based. We describe the dynamics, implementation, and operation of synchronverters. The real and reactive power delivered by synchronverters connected in parallel and operated as generators can be automatically shared using the well-known frequency- and voltage-drooping mechanisms. Synchronverters can be easily operated also in island mode, and hence, they provide an ideal solution for microgrids or smart grids. Both simulation and experimental results are given to verify the idea.

The age of multilevel converters arrives

Abstract: This work is devoted to review and analyze the most relevant characteristics of multilevel converters, to motivate possible solutions, and to show that we are in a decisive instant in which energy companies have to bet on these converters as a good solution compared with classic two-level converters. This article presents a brief overview of the actual applications of multilevel converters and provides an introduction of the modeling techniques and the most common modulation strategies. It also addresses the operational and technological issues.