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Enhanced frequency droop method for decentralized power sharing control in DC microgrids
, Article IEEE Journal of Emerging and Selected Topics in Power Electronics ; Volume 9, Issue 2 , 2021 , Pages 1290-1301 ; 21686777 (ISSN) ; Peyghami, S ; Mokhtari, H ; Blaabjerg, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
This article proposes two novel approaches to improve the superimposed frequency droop scheme for the control of dc microgrids (MGs). Conventional voltage-based control strategies suffer from issues such as undesirable voltage regulations, poor power sharing among the sources, and negative effects of line resistances on the equivalent droop characteristics. To overcome these challenges, a superimposed frequency droop scheme has been introduced. However, this method suffers from three major issues: 1) instability in terms of load variation, which is due to the location of system dominant poles; 2) limitation in system loading due to the limitation in the transferred reactive power; and 3)...
Development of Optimal Operating Model for Electrical Energy Distribution Systems with DG Units
, M.Sc. Thesis Sharif University of Technology ; Saboohi, Yadollah (Supervisor)
Abstract
The objective of the present research work has been the development of a model of optimal distribution electrical energy which may include distributed generators. Electrical distribution company has the option of receiving electric power from distributed generators owned by customers (Private Companies), DGs belonging to the electrical distribution company and purchase of power from market (high voltage network). The electrical distribution company would alternatively be able to sell surplus of its generation to the power market (high voltage network). The model of distribution system depicts the flow of electricity in each hour interval. The restrictions and bounds are the flows in each...
Voltage Regulation in DC Microgrids in Superimposed Frequency Droop Method
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
Environmental problems and limitation in fossil fuels have increased the application of renewable energy sources (RES) and distributed generations (DG). Due to the DC nature of most loads and DGs, DC microgrids provide a suitable structure to integrate different kinds of DGs and loads. Undesirable voltage regulation and poor power sharing among the sources in conventional voltage-based control methods are solved by the superimposed droop frequency method. However, the superimposed droop frequency scheme suffers from three major problems which are (i) instability in terms of load variation, (ii) limitation in the system maximum loading which is due to the limitation in the transferred...
Automatic superimposed droop frequency control scheme for dc microgrids
, Article 2019 International Aegean Conference on Electrical Machines and Power Electronics, ACEMP 2019 and 2019 International Conference on Optimization of Electrical and Electronic Equipment, OPTIM 2019, 27 August 2019 through 29 August 2019 ; 2019 , Pages 120-125 ; 9781538676875 (ISBN) ; Mokhtari, H ; Poshtan, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
This paper proposes a control strategy to improve the superimposed droop frequency control scheme in DC microgrids. Conventional droop-based schemes for DC microgrids control suffer from issues such as inaccurate power sharing among the sources, voltage control with insufficient quality, and adverse effect of the line resistance on the droop characteristic. To overcome these challenges, the superimposed droop frequency method has been introduced. However, the stable operation in terms of the load variations and improper voltage quality are still the challenges with this prior-art method due to the injected AC voltages. In this paper, a method is proposed to solve the stability problem and...
A superimposed frequency method with an adaptive droop characteristic for DC microgrids
, Article 2019 International Aegean Conference on Electrical Machines and Power Electronics, ACEMP 2019 and 2019 International Conference on Optimization of Electrical and Electronic Equipment, OPTIM 2019, 27 August 2019 through 29 August 2019 ; 2019 , Pages 447-452 ; 9781538676875 (ISBN) ; Mokhtari, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
This paper proposes an adaptive droop characteristic to enhance the superimposed droop frequency scheme for the control of DC microgrids. Conventional superimposed droop frequency scheme solves the poor current sharing and undesirable voltage regulation issues in DC microgrid. However, this method suffers from two main problems which are (i) instability in terms of load variation due to the limitation in transferrable reactive power, and (ii) poor voltage quality caused by the injected AC voltages in the DC system. In this paper, an adaptive droop characteristic is proposed to decrease the transferred reactive power and mitigate system overall voltage quality, and its performance is verified...