The ever increasing progress of high-voltage high-power fully controlled semiconductor technology continues to have a significant impact on the development of advanced power electronic apparatus used to support optimized operations and efficient management of electrical grids, which, in many cases, are fully or partially deregulated networks. Developments advance both the HVDC power transmission and the flexible ac transmission system technologies. In this paper, an overview of the recent advances in the area of voltage-source converter (VSC) HVdc technology is provided. Selected key multilevel converter topologies are presented. Control and modeling methods are discussed. A list of VSC-based HVdc installations worldwide is included. It is confirmed that the continuous development of power electronics presents cost-effective opportunities for the utilities to exploit, and HVdc remains a key technology. In particular, VSC-HVdc can address not only conventional network issues such as bulk power transmission, asynchronous network interconnections, back-to-back ac system linking, and voltage/stability support to mention a few, but also niche markets such as the integration of large-scale renewable energy sources with the grid and most recently large onshore/offshore wind farms.

VSC-Based HVDC Power Transmission Systems: An Overview

Solid-state switch-mode rectification converters have reached a matured level for improving power quality in terms of power-factor correction (PFC), reduced total harmonic distortion at input AC mains and precisely regulated DC output in buck, boost, buck-boost and multilevel modes with unidirectional and bidirectional power flow. This paper deals with a comprehensive review of improved power quality converters (IPQCs) configurations, control approaches, design features, selection of components, other related considerations, and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of IPQC technology to researchers, designers and application engineers working on switched-mode AC-DC converters. A classified list of more than 450 research publications on the state of art of IPQC is also given for a quick reference.

/pdf/a-review-of-single-phase-improved-power-quality-ac-dc-2pm6h4zjxq.pdf

A review of single-phase improved power quality AC-DC converters

In this paper, the principle of modularity is used to derive the different multilevel voltage and current source converter topologies. The paper is primarily focused on high-power applications and specifically on high-voltage dc systems. The derived converter cells are treated as building blocks and are contributing to the modularity of the system. By combining the different building blocks, i.e., the converter cells, a variety of voltage and current source modular multilevel converter topologies are derived and thoroughly discussed. Furthermore, by applying the modularity principle at the system level, various types of high-power converters are introduced. The modularity of the multilevel converters is studied in depth, and the challenges as well as the opportunities for high-power applications are illustrated.

Modular Multilevel Converters for HVDC Applications: Review on Converter Cells and Functionalities

New regulations impose more stringent limits on current harmonics injected by power converters that are achieved with pulsewidth-modulated (PWM) rectifiers. In addition, several applications demand the capability of power regeneration to the power supply. This work presents the state of the art in the field of regenerative rectifiers with reduced input harmonics and improved power factor. Regenerative rectifiers are able to deliver energy back from the dc side to the ac power supply. Topologies for single- and three-phase power supplies are considered with their corresponding control strategies. Special attention is given to the application of voltage- and current-source PWM rectifiers in different processes with a power range from a few kilowatts up to several megawatts. This paper shows that PWM regenerative rectifiers are a highly developed and mature technology with a wide industrial acceptance.

http://www.lcda.cl/descargas/rodriguez_dixon_pont_espinoza_lezana05.pdf

PWM regenerative rectifiers: state of the art

Power quality problems associated with distributed power (DP) inverters, implemented in large numbers onto the same distribution network, are investigated. Currently, these power quality problems are mainly found in projects with large penetration of photovoltaics (PV) on rooftops of houses and commercial buildings. The main object of this paper is to analyze the observed phenomena of harmonic interference of large populations of these inverters and to compare the network interaction of different inverter topologies and control options. These power quality phenomenons are investigated by using extensive laboratory experiments, as well as computer modeling of different inverter topologies. A complete network simulation study on an existing residential network with large penetration of PVs, is included.

Harmonic interaction between a large number of distributed power inverters and the distribution network

Preface Introduction Harmonic Analysis Harmonic Sources - The Static Convertor Other Harmonic Sources Harmonic Effects: Within the Power System Interference with Communications Power System Harmonic Measurements Transducers and Data Transmission Standards for the Limitation and Control of Power System Harmonics Harmonic Penetration in A.C. Systems Harmonic Elimination Index.

Power System Harmonics

Fourier Analysis. Transmission Systems. Direct Harmonic Solutions. AC--DC Conversion----Frequency Domain. Harmonic Instabilities. Machine Non--linearities----Harmonic Domain. AC--DC Conversion----Harmonic Domain. Iterative Harmonic Analysis. Converter Harmonic Impedances. Appendices. Index.

Power System Harmonic Analysis

Power System Harmonic Analysis: Arrillaga/Power System Harmonic Analysis

An old concept proposed to double the pulse number of a line commutated converter and designated "dc-ripple reinjection," is made more effective by the use of self-commutating reinjection switches, such as GTO or IGCT. It is shown that the self-commutating reinjection switches can be controlled to force the thyristor valve currents to commutate independently from their respective line voltages. EMTDC-PSCAD simulation is used to verify that this effect adds reactive power controllability, as well as pulse multiplication, to the conventional thyristor converter.

/pdf/a-current-reinjection-scheme-that-adds-self-commutation-and-1gbzuwjy3o.pdf

A current reinjection scheme that adds self-commutation and pulse multiplication to the thyristor converter

A new self-commutated AC–DC converter is proposed based on the reinjection of multilevel DC pulses via the mid-point of the series double-bridge converter using a GTO-switched multitapped single-phase transformer. The ideal reinjection waveform for complete elimination of the harmonic content of the AC-side current is derived and a practical approximation proposed to increase the pulse number of double-bridge converters to any multiple of 12. A 60-pulse configuration is analysed in detail to show effectiveness on both the AC and DC sides of the converter.

Jos Arrillaga

Papers

Power System Harmonics

Power System Harmonic Analysis

Power System Harmonic Analysis: Arrillaga/Power System Harmonic Analysis

A current reinjection scheme that adds self-commutation and pulse multiplication to the thyristor converter

Multilevel current reinjection self-commutated HVDC converter