Ideal current‐based distributed control to compensate line impedance in DC microgrid. Issue 7 (3rd May 2018)

• Record Type: Journal Article
• Authors: Islam, Shirazul; Agarwal, Shyam; Shyam, A.B.; Ingle, Anoop; Thomas, Soumya; Anand, Sandeep; Sahoo, Soumya Ranjan
• Is Part Of: IET power electronics. Volume 11:Issue 7(2018)
• Page Start: 1178
• Page End: 1186
• Publication Date: 2018-05-03
• Subjects: distributed power generation -- distributed control -- power distribution control -- PI control; characteristic equation -- communication delay -- low‐bandwidth communication -- full communication -- distributed secondary controller -- winding‐up phenomenon -- distributed proportional‐integral control -- droop gain -- droop characteristics -- cable impedances interconnection -- droop controllers -- proportional power sharing -- DC microgrid -- line impedance compensation -- ideal current‐based distributed control; Power electronics -- Periodicals; 621.31705
• DOI: 10.1049/iet-pel.2017.0531
• Languages: English
• ISSNs: 1755-4535

Abstract

Abstract : To achieve proportional power sharing among similar sources in DC microgrid, droop controllers are used. However, due to interconnecting cable impedances, power shared by the sources deviate from their desired values. To alleviate this problem, techniques utilising shift in droop characteristics and/or modification in droop gain are suggested in literature. Methods which use both of them offer better performance due to higher degree of freedom in control. However, these methods utilise distributed proportional‐integral control, which leads to winding‐up phenomenon. To address this problem, a distributed secondary controller using full communication is proposed. The current of each source is shared with other sources using low‐bandwidth communication. Using this information, each source calculates the ideal value of current to be supplied, which is then used to update its droop gain. To improve the average system voltage, shifting of droop characteristics is incorporated. Detailed small signal model of the proposed controller is developed. Effect of communication delay on the performance of the proposed controller is analysed using the characteristic equation of the system. To evaluate the performance of the proposed scheme, detailed simulation studies are carried out. A scaled down laboratory prototype is developed to determine the viability of the proposed controller.