Modeling and Performance Assessment of the Split-Pi Used as a Storage Converter in All the Possible DC Microgrid Scenarios. Part I: Theoretical Analysis

Abstract

The integration of an electrical storage system (ESS) into a DC microgrid using a bidirectional DC/DC converter provides substantial benefits but requires careful design. Among such converter topologies, the Split-pi converter presents several merits at the cost of non-isolated operation. However, the few works in the literature on the Split-pi presented only closed-loop control with a single control loop; furthermore, they neglected the reactive components’ parasitic resistances and did not perform any experimental validation. This work aimed at investigating the use of the Split-pi converter as a power interface between an ESS and a DC microgrid. Five typical microgrid scenarios are presented, where each of which requires a specific state-space model and a suitable control scheme for the converter to obtain high performance. In this study, two different state-space models of the converter that consider the parasitic elements are presented, the control schemes are discussed, and criteria for designing the controllers are also given. Several simulations, as well as experimental tests on a prototype realized in the lab, were performed to validate the study. Both the simulation and experimental results will be presented in part II of this work. The proposed approach has general validity and can also be followed when other bidirectional DC/DC converter topologies are employed to interface an ESS with a DC microgrid.

Modeling and Performance Assessment of the Split-Pi Used as a Storage Converter in All the Possible DC Microgrid Scenarios. Part II: Simulation and Experimental Results

“…This paper is the second part of a work aimed at analyzing all the scenarios in which a bidirectional DC/DC converter is used to interface an ESS with a DC microgrid. Part I dealt with the theoretical aspects of the problem [28]. First, the five possible DC microgrid scenarios were identified.…”

High-Efficiency and High-Performance Power Electronics for Power Grids and Electrical Drives

“…This Special Issue includes ten contributions on various techniques aimed at improving the efficiency and performance in power electronics applications for power grids and electrical drives [1][2][3][4][5][6][7][8][9][10]. Such articles were authored by international research teams from several countries and covered different topics.…”

“…(a) Power converters used to interface RESs and ESSs with microgrids [1,3,5,7,8,10] or to recharge ESSs in electric vehicles [9]; (b) Performance increase in VSDs and direct online induction motors [4,6]; (c) Application of electrical loss minimization techniques to microgrids based on RESs [2].…”

“…Other contributions that fall into category (a) are [7,8] by Luna et al These papers were focused on the use of bidirectional DC-DC converters to integrate an ESS into a DC microgrid, ensuring stable operation and good dynamic performance. The authors showed that this integration deserves careful design because the ESS converter is required to work in different scenarios depending on the microgrid configuration.…”

Modeling and Design of Split-Pi Converter

“…Few details pertaining to the control design with controlled current or voltage feedback and dc link voltage have been presented. Elaborate state-space models of the SPC with respect to energy storage interface of stiff and nonstiff dc microgrids have been discussed in [21]. A unique control strategy for controlling the flywheel system using the SPC in rural applications has been described in [22].…”