Serhiy Bozhko

Bio: Serhiy Bozhko is an academic researcher from University of Nottingham. The author has contributed to research in topics: Electric power system & Electric power. The author has an hindex of 27, co-authored 217 publications receiving 2648 citations. Previous affiliations of Serhiy Bozhko include The University of Nottingham Ningbo China & Instituto Nacional de Técnica Aeroespacial.

Control of Offshore DFIG-Based Wind Farm Grid With Line-Commutated HVDC Connection

Abstract: The paper considers a control solution for integration of large offshore doubly fed induction generator based wind farms with a common collection bus, controlled by a static compensator, into the main onshore grid, using line-commutated high-voltage direct current connection. The paper's main focus is a mathematically grounded study of the power system interactions. That study produced an appropriate plant model for formal control design. A design procedure is described and the controlled system is validated using power systems computer-aided design/electromagnetic transient program simulations, which confirm the high performance of the proposed control strategy in both normal operation and fault conditions

On-Board Microgrids for the More Electric Aircraft—Technology Review

Abstract: This paper presents an overview of technology related to on-board microgrids for the more electric aircraft. All aircraft use an isolated system, where security of supply and power density represents the main requirements. Different distribution systems (ac and dc) and voltage levels coexist, and power converters have the central role in connecting them with high reliability and high power density. Ensuring the safety of supply with a limited redundancy is one of the targets of the system design since it allows increasing the power density. This main challenge is often tackled with proper load management and advanced control strategies, as highlighted in this paper.

Frequency Control Design for Offshore Wind Farm Grid With LCC-HVDC Link Connection

Abstract: This paper considers the formal design for the grid frequency control in an offshore wind farm connected with line-commutated converter high voltage dc (HVDC) link. The control paradigm is based on using the grid frequency control to regulate the HVDC rectifier firing angle or dc-link current and hence control the power flow in the system. The dynamic behaviors of the system are verified by comparing the response from derived transfer functions and PSCAD simulations; hence the grid frequency controllers are designed. The control system performance has been validated by simulations of normal operation and fault regimes. The work provides a good basis for wider research investigation into wind farm operation.

Comparative Stability Analysis of Droop Control Approaches in Voltage-Source-Converter-Based DC Microgrids

Abstract: Droop control has been widely applied in dc microgrids (MGs) due to its inherent modularity and ease of implementation Among the different droop control methods that can be adopted in dc MGs, two options have been considered in this paper: I – V and V – I droop I – V droop controls the dc current depending on the dc voltage while V – I droop regulates the dc voltage based on the output current The paper proposes a comparative study of V – I / I – V droop control approaches in dc MGs focusing on steady-state power-sharing performance and stability The paper presents the control scheme for current-mode ( I – V droop) and voltage-mode ( V – I droop) systems, derives the corresponding output impedance of the source subsystem, including converters dynamics, and analyzes the stability of the power system when supplying constant power loads The paper first investigates the impact on stability of the key parameters including droop gains, local control loop dynamics, and number of sources and then performs a comparison between current-mode and voltage-mode systems in terms of stability In addition, a generalized analytical impedance model of a multisource, multiload power system is presented to investigate stability in a more realistic scenario For this purpose, the paper proposes the concept of “global droop gain” as an important factor to determine the stability behaviour of a parallel sources based dc system The theoretical analysis has been validated with experimental results from a laboratory-scale dc MG

An Improved Voltage Compensation Approach in a Droop-Controlled DC Power System for the More Electric Aircraft

Abstract: This paper proposes an improved voltage regulation method in a multisource-based dc electrical power system in the more electric aircraft. The proposed approach, which can be used in terrestrial dc microgrids as well, effectively improves the load sharing accuracy under high droop gain circumstance with consideration of cable impedance. Since no extra communication line and controllers are required, it is easily implemented and also increases the system modularity and reliability. By using the proposed approach, the dc transmission losses can be reduced and the system stability is not deteriorated for normal and fault scenarios. In this paper, optimal droop gain settings are investigated and the selection of individual droop gains as well as the proportional power sharing ratio has been described. Simulation and experimental results validate the effectiveness of the proposed method.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

VSC-Based HVDC Power Transmission Systems: An Overview

Abstract: 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.

More Electric Aircraft: Review, Challenges, and Opportunities for Commercial Transport Aircraft

Abstract: Similar to the efforts to move toward electric vehicles, much research has focused on the idea of a more electric aircraft (MEA). The motivations for this research are similar to that for vehicles and include goals to reduce emissions and decrease fuel consumption. In traditional aircraft, multiple systems may use one type or a combination of types of energy, including electrical, hydraulic, mechanical, and pneumatic energy. However, all energy types have different drawbacks, including the sacrifice of total engine efficiency in the process of harvesting a particular energy, as with hydraulic and pneumatic systems. The goal for future aircraft is to replace most of the major systems currently utilizing nonelectric power, such as environmental controls and engine start, with new electrical systems to improve a variety of aircraft characteristics, such as efficiency, emissions, reliability, and maintenance costs. This paper provides an in-depth look into how the systems have—or will be—changed. Future aircraft capabilities such as electric taxi and gas–electric propulsion for aircraft are also included for discussion. Most recent commercial transport aircrafts are described as the current state-of-the-art electric aircraft system. Future goals, including those of NASA, are presented for future advances in MEA.

Power Electronics Converters Applications And Design

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