Energy Storage Sharing Strategy in Distribution Networks Using Bi-level Optimization Approach

In this paper, we address the energy storage management problem in distribution networks from the perspective of an independent energy storage manager (IESM) who aims to realize optimal energy storage sharing with multi-objective optimization, i.e., optimizing the system peak loads and the electricity purchase costs of the distribution company (DisCo) and its customers. To achieve the goal of the IESM, an energy storage sharing strategy is therefore proposed, which allows DisCo and customers to control the assigned energy storage. The strategy is updated day by day according to the system information change. The problem is formulated as a bi-level mathematical model where the upper level model (ULM) seeks for optimal division of energy storage among Disco and customers, and the lower level models (LLMs) represent the minimizations of the electricity purchase costs of DisCo and customers. Further, in order to enhance the computation efficiency, we transform the bi-level model into a single-level mathematical program with equilibrium constraints (MPEC) model and linearize it. Finally, we validate the effectiveness of the strategy and complement our analysis through case studies

Bis(pentane-2,4-dionato-κ2 O,O′)bis­[4,4,5,5-tetra­methyl-2-(4-pyridyl)­imidazoline-1-oxyl 3-oxide-κN 2]manganese(II)

The title compound, [Mn(C5H7O2)2(C12H16N3O2)2], is isostructural with its NiII-containing analogue [Hao, Mu & Kong (2008 ▶). Acta Cryst. E64, m957]. The asymmetric unit comprises one-half of the mol­ecule and the MnII ion is located on an inversion centre. The coordination geometry around the MnII ion is slightly distorted octa­hedral, comprised of four O and two N atoms, in which the four O atoms in the equatorial plane come from two pentane-2,4-dionate ligands and the two N atoms in the axial coordination sites from 4,4,5,5-tetra­methyl-2-(4-pyrid­yl)imidazoline-1-oxyl 3-oxide

Commutation Behavior and Stray Inductance Analysis of a FC-3L-BDC Phase-Leg PEBB

The bidirectional dc-dc converter is a critical component for extending the use of renewable energy and improving the efficiency of high-power electronic systems. This paper presents the analysis of the stray inductance of a commutation loop and the commutation behavior of IGBT devices in a flying capacitor three-level bidirectional DC-DC converter (FC-3L-BDC) phase-leg power electronic building block (PEBB). An FC-3L-BDC phase-leg PEBB was designed as an example, which can be used to build 400 kW to MW-grade light rail train chargers, battery energy storage interface converters, or metro regenerative braking energy recovery converters with a single PEBB or several PEBBs interleaved parallel. In order to optimize the stray inductance of commutation paths and realize snubberless operation, a five-layer laminated bus bar was carefully designed, and the stray inductance of the bus bar was extracted by three-dimensional finite element analysis simulation. To obtain higher accuracy, the stray inductances of IGBT devices and capacitors were extracted from the test instead of their datasheets. Then, the accuracy of the commutation loop stray inductance analysis method was verified by practical experiments. The impact of the stray inductance of the commutation loop on the commutation behavior of IGBT devices was analyzed, and the switching characteristics of IGBT devices were measured under maximum DC-link voltage and entire current rating range at the temperatures of −40 °C, 25 °C, and 150 °C, respectively, finding that neither the excessive turn-off overvoltage of IGBTs nor the snappy reverse recovery of FWDs was observed

Commutation Behavior and Stray Inductance Analysis of a FC-3L-BDC Phase-Leg PEBB

The bidirectional dc-dc converter is a critical component for extending the use of renewable energy and improving the efficiency of high-power electronic systems. This paper presents the analysis of the stray inductance of a commutation loop and the commutation behavior of IGBT devices in a flying capacitor three-level bidirectional DC-DC converter (FC-3L-BDC) phase-leg power electronic building block (PEBB). An FC-3L-BDC phase-leg PEBB was designed as an example, which can be used to build 400 kW to MW-grade light rail train chargers, battery energy storage interface converters, or metro regenerative braking energy recovery converters with a single PEBB or several PEBBs interleaved parallel. In order to optimize the stray inductance of commutation paths and realize snubberless operation, a five-layer laminated bus bar was carefully designed, and the stray inductance of the bus bar was extracted by three-dimensional finite element analysis simulation. To obtain higher accuracy, the stray inductances of IGBT devices and capacitors were extracted from the test instead of their datasheets. Then, the accuracy of the commutation loop stray inductance analysis method was verified by practical experiments. The impact of the stray inductance of the commutation loop on the commutation behavior of IGBT devices was analyzed, and the switching characteristics of IGBT devices were measured under maximum DC-link voltage and entire current rating range at the temperatures of −40 °C, 25 °C, and 150 °C, respectively, finding that neither the excessive turn-off overvoltage of IGBTs nor the snappy reverse recovery of FWDs was observed

Distributed Coordination of EV Charging with Renewable Energy in a Microgrid of Buildings

© 2010-2012 IEEE. With the rapid development of electric vehicles (EVs), the consequent charging demand represents a significant new load on the power grids. The huge number of high-rise buildings in big cities and modern technological advances have created conditions to mount on-site wind power generators on the buildings. Since modern buildings are usually equipped with large parking lots for EVs, it shows vital practical significance to utilize the on-site wind power generation to charge EVs parked in the buildings. In this paper, we first use a case study in Beijing to show that the on-site wind power generation of high-rise buildings can potentially support all the EVs in the city. Considering that the charging demand of EVs usually does not align with the uncertain wind power, the coordination of EV charging with the locally generated wind power in a microgrid of buildings is investigated and three main contributions are made. First, we investigate the problem and formulate it as a Markov decision process, which incorporates the random driving requirements of EVs among the buildings. Second, we develop a distributed simulation-based policy improvement (DSBPI) method, which can improve from heuristic and experience-based policies. Third, the performance of the distributed policy improvement method is proved. We compare DSBPI with a central version method on two case studies. The DSBPI method demonstrates good performance and scalability.status: publishe

Integration of Printed Electronics in Potted Power Electronic Modules

Printed electronics on flexible substrates are attractive for various applications in the field of sensor technology. This work aims at investigating the integration of printed electronics in potted power-electronic modules. Silver (Ag) interdigitated structures with varying electrode dimensions were printed on polyimide and polyethylene terephthalate foil and afterwards potted with Wacker SilGel® 612. Printing ability, adhesion to potting material, and contacting were investigated. Capacitance-voltage measurements were performed to characterize the behavior of printed devices in contact with potting material. Peel tests were performed in order to gain information on the adhesion of different substrate materials to the SilGel. Further, different contacting methods were evaluated. Based on the presented results, the integration of printed electronics in potted power electronic modules is highly feasible and could allow the facile addition of monitoring devices

Vias in DBC substrates for embedded power modules

This paper encompasses an evaluation of five different approaches to produce electrical vias in DBC (Direct Bonded Copper) substrates. The investigated methods of producing vias are based on laser drilling of different via layouts in the DBC substrates. In the next step, a stencil printing, dispensing and mechanical pressing process were tested for filling the via holes. As filling material, copper, silver pastes and copper rivets were used to enable the electrical connection. Before the experiments, electrical simulations have been performed in order to analyse the optimal via layout in the DBC substrates. It could be validated that at high frequency range (1 GHz), the current density distribution improves through the increase of via pitch, via diameter and via numbers. Combined with silver paste as filling material, the electrical characteristics of produced blind-hole vias could be improved compared to the use of copper paste and copper rivets. In conclusion, potential application possibilities for vias in DBC substrate, like three-dimensional power modules, multilayer DBC stacks and chip embedding concepts are discussed

Virally-induced expression of GABAA receptor δ subunits following their pathological loss reveals their role in regulating GABAA receptor assembly.

Decreased expression of the δ subunit of the GABAA receptor (GABAAR) has been found in the dentate gyrus in several animal models of epilepsy and other disorders with increased excitability and is associated with altered modulation of tonic inhibition in dentate granule cells (GCs). In contrast, other GABAAR subunits, including α4 and γ2 subunits, are increased, but the relationship between these changes is unclear. The goals of this study were to determine if viral transfection of δ subunits in dentate GCs could increase δ subunit expression, alter expression of potentially-related GABAAR subunits, and restore more normal network excitability in the dentate gyrus in a mouse model of epilepsy. Pilocarpine-induced seizures were elicited in DOCK10-Cre mice that express Cre selectively in dentate GCs, and two weeks later the mice were injected unilaterally with a Cre-dependent δ-GABAAR viral vector. At 4-6 weeks following transfection, δ subunit immunolabeling was substantially increased in dentate GCs on the transfected side compared to the nontransfected side. Importantly, α4 and γ2 subunit labeling was downregulated on the transfected side. Electrophysiological studies revealed enhanced tonic inhibition, decreased network excitability, and increased neurosteroid sensitivity in slices from the δ subunit-transfected side compared to those from the nontransfected side of the same pilocarpine-treated animal, consistent with the formation of δ subunit-containing GABAARs. No differences were observed between sides of eYFP-transfected animals. These findings are consistent with the idea that altering expression of key subunits, such as the δ subunit, regulates GABAAR subunit assemblies, resulting in substantial effects on network excitability