Embedded Energy Storage Research Articles

A two-layer strategy for sustainable energy management of microgrid clusters with embedded energy storage system and demand-side flexibility provision

The intermittent nature of renewable energy generation and the fluctuating demands pose persistent challenges in microgrid operations. In response, stakeholders and operators have turned to clustering the geographically adjacent microgrids as a solution. In this context, this paper introduces a novel two-layer energy management strategy for microgrid clusters, utilizing demand-side flexibility and the capabilities of shared battery energy storage (SBES) to minimize operational costs and emissions, while ensuring a spinning reserve within individual microgrids to prevent load-shedding. In the lower layer, the proposed approach devises optimal day-ahead operation policies, while the upper layer employs a cooperative strategy to further optimize the operational efficiency across the entire cluster. The energy management problem is accurately formulated as a mixed integer quadratic programming (MIQP) optimization, which incorporates linear terms in the problem's constraints. The formulation accounts for operational costs associated with SBES including expenses of charging/discharging and changes in operating states (CiOS). Real-world case studies with a cluster of three microgrids in Australia validate the effectiveness of this approach. Results show a reduction in operational costs for the base case scenario by 6.96 % compared to conventional microgrid management strategies. Sensitivity analyses further demonstrate the economic benefits of varying SBES capacity and flexibility pricing, with savings ranging from 6.5 % to 8.1 %. The proposed strategy also reduces CO2 emissions by up to 11.6 %, while improving system reliability. This strategy holds promise for integration into distributed energy systems with high renewable penetration and clustered local grids, offering significant advantages for utility operators and end-users through improved energy efficiency and reduced emissions.

Detailed Nonlinear Modeling and High-Fidelity Parallel Simulation of MMC With Embedded Energy Storage for Wind Farm Grid Integration

Detailed Nonlinear Modeling and High-Fidelity Parallel Simulation of MMC With Embedded Energy Storage for Wind Farm Grid Integration

Sub-mm3 dimensional scaling of fully-integrated additively-fabricated microsupercapacitors for embedded energy storage applications

Microsupercapacitors (MSCs) are attractive energy devices for applications in IoT, wireless sensors, and other microelectronic systems due to their small footprints.

Modeling of MMC-based STATCOM with embedded energy storage for the simulation of electromagnetic transients

Modeling of MMC-based STATCOM with embedded energy storage for the simulation of electromagnetic transients

Application of MMC with Embedded Energy Storage for Overvoltage Suppression and Fault Ride-through Improvement in Series LCC-MMC Hybrid HVDC System

Application of MMC with Embedded Energy Storage for Overvoltage Suppression and Fault Ride-through Improvement in Series LCC-MMC Hybrid HVDC System

Design and implementation of a novel multi-faceted-efficient pneumatic dual-axis solar tracker

PurposePhotovoltaic (PV) systems are experiencing exponential growth due to environmental concerns, unlimited and ubiquitous solar energy, and starting-to-make-sense panel costs. Alongside designing more efficient solar panels, installing solar trackers and special circuitry for optimizing power delivery to the load according to a maximum power point tracking (MPPT) algorithm are other ways of increasing efficiency. However, it is critical for any efficiency increase to account for the power consumption of any amendments. Therefore, this paper aims to propose a novel tracker while using MPPT to boost the PV system's actual efficiency accounting for the involved costs.Design/methodology/approachThe proposition is an experimental pneumatic dual-axis solar tracker using light-dependent resistor (LDR) sensors. Due to its embedded energy storage, the pneumatic tracker offers a low duty-cycle operation leading to tracking energy conservation, fewer maintenance needs and scalability potential. While MPPT assures maximum load power delivery, the solar PV's actual delivered power is calculated for the first time, accounting for the solar tracking and MPPT power costs.FindingsThe experiments' results show an increase of 37.6% in total and 35.3% in actual power production for the proposed solar tracking system compared to the fixed panel system, with an MPPT efficiency of 90%. Thus, the pneumatic tracking system offers low tracking-energy consumption and good actual power efficiency. Also, the newly proposed pneumatic stimulant can significantly simplify the tracking mechanism and benefit from several advantages that come along with it.Originality/valueTo the best of the authors’ knowledge, this work proposes, for the first time, a single-motor pneumatic dual-axis tracker with less implementation cost, less frequent operation switching and scalability potential, to be developed in future works. Also, the pneumatic proposal delivers high actual power efficiency for the first time to be addressed.

Mechanical Properties of Prismatic Li-Ion Batteries—Electrodes, Cells, and Stacks

Abstract Mechanical abusive loadings, as an inevitable consequence of road accidents, can damage the embedded energy storage system in an electric vehicle and deform its constitutive parts, e.g., the lithium-ion batteries. Therefore, to study the mechanical responses of these batteries and avoid expensive testing equipment and rigorous safety percussions, researchers are propelled toward utilizing numerical models. Computationally cost-efficient homogenized finite element models that represent the whole battery in the form of a uniform medium are the most feasible solution, especially in large-scale battery stacks simulations. Compared to the other form factors of the batteries, prismatic cells have been understudied even though they have higher packaging efficiency, by making optimal use of space. In this article, a comprehensive homogenization and failure calibration method was developed for these prismatic cells. The homogenization was done through extensive uniaxial components tests of the jellyroll and the shell casing. In addition, biaxial tensile tests and simulations were used to calibrate strain-based failure criteria for the components. The calibrated homogenized model is validated in various punch loading scenarios and used in the characterization of the load–displacement responses and failure modes of the stacked cell configurations. In the stacked simulations, due to the cushion-like behavior of the other cells, the failure happens in higher values of displacement compared to a single cell. However, the normalized intrusion percentages for the battery stacks are lower compared to a single battery cell. This emphasizes the importance of the safety assessment of an electric vehicle based on the failure analysis of the battery stacks rather than a single cell. This goal would be feasible through simulations of only homogenized cell models in the stacked configurations, which are elaborated in this article for prismatic cells.

Electromechanical transient modelling and application of modular multilevel converter with embedded energy storage

This paper studies the electromechanical transient modelling techniques of the modified modular multilevel converter (MMC), named active MMC, which is equipped with embedded energy storage in submodules. Firstly, the mathematical model of the active MMC and its equivalent circuits at the AC and DC sides are established. Then, the control scheme of active MMC that focus on the cooperation of the MMC converter and the energy storage submodules is illustrated. The proposed electromechanical transient model are implemented on PSS/E and compared with the electromagnetic transient model on PSCAD in a two terminal active MMC sytem; the results of the active MMC system under AC and DC fault prove the validity of the proposed model. Lastly, stability studies of the practical system are carried out, and the simulation results prove the improvement by the application of the active MMC on the rotor angle stability and frequency stability.

TMP origami jumping mechanism with nonlinear stiffness

Via numerical simulation and experimental assessment, this study examines the use of origami folding to develop robotic jumping mechanisms with tailored nonlinear stiffness to improve dynamic performance. We propose a multifunctional structure where the load-carrying skeleton of the structure acts as the energy-storage medium at the same time. Specifically, we use Tachi–Miura polyhedron (TMP) bellow origami—which exhibits a nonlinear ‘strain-softening’ force-displacement curve—as a jumping robotic skeleton with embedded energy storage. TMP’s nonlinear stiffness allows it to store more energy than a linear spring and offers improved jumping height and airtime. Moreover, the nonlinearity can be tailored by directly changing the underlying TMP crease geometry. A critical challenge is to minimize the TMP’s hysteresis and energy loss during its compression stage right before jumping. So we used the plastically annealed lamina emergent origami (PALEO) concept to modify the TMP creases. PALEO increases the folding limit before plastic deformation occurs, thus improving the overall strain energy retention. Jumping experiments confirmed that a nonlinear TMP mechanism achieved roughly 9% improvement in air time and a 13% improvement in jumping height compared to a ‘control’ TMP sample with a relatively linear stiffness. This study’s results validate the advantages of using origami in robotic jumping mechanisms and demonstrate the benefits of utilizing nonlinear spring elements for improving jumping performance. Therefore, they could foster a new family of energetically efficient jumping mechanisms with optimized performance in the future.

Analysis on boundary conditions of soft switching for DC electric spring with parallel topology

The concept of DC electric spring (DCES) has been introduced some years ago to solve the voltage stabilisation issue caused by the high penetration of intermittent renewable energy sources (RESs) into DC power systems. Recently, a featured DCES topology has been proposed, comprising an isolated three-port DC/DC converter and an embedded energy storage system. The three ports are connected to a DC power system at the supply side, the critical load (CL) and the non-critical load (NCL) at the user side, whilst the energy storage system is paralleled at the CL port. To improve the performance of the topology, this paper investigates the chance of making soft the switching of the DCES converters. After the DCES operation is analysed, equations describing the currents transients during switching have been worked out, from which the boundary conditions for zero-voltage switching (ZVS) to occur are formulated and the resultant ZVS zone is illustrated with the help of visual graphs. The boundary conditions are examined to evaluate how the circuit parameters influence the extension of the ZVS zone. The examination shows that a suitable selection of the parameters widens the ZVS zone notably; its optimal extension is then found for a case study. The effectiveness of the ZVS findings for the featured DCES topology is validated by both simulation and experiment results.

Intermittent Embedding of Wire into 3D Prints for Wireless Power Transfer

3D printing is rapidly moving into the realm of electronics and fully functioning devices. These devices include 3D printed plastic parts with conductive materials embedded in the plastic using additive manufacturing techniques to produce functioning circuits. However, current materials and techniques limit the amount of power that can be supplied to embedded circuits. The state of the art for embedding traditional conductive materials, such as solid metal wire, uses the continuous application of heat. Continuous heat often overheats and damages the previously printed layer of plastic material potentially ruining the part and device. Additionally, current devices with embedded electronics require either external power or embedded energy storage such as a battery. Both the continuous application of heat and the need for power affect design choices and can severely limit potential use cases of the device. This research presents analysis and demonstration of embedding traditional copper wires onto a plastic substrate using intermittent application of heat and pressure using a traditional Fused Filament Fabrication plastic print nozzle at specific points, herein referred to as embedding instances. Detailed analysis of the interaction of a heating element (print nozzle), metal wire, and plastic substrate are provided to give context for the new technology presented. High thermal conductivity in the wire conducts heat away from the heating element quickly, and continuous application of heat to the wire can melt the plastic substrate along the wire, damaging previously embedded sections of wire, especially at the start of the embedding process and after turning sharp corners while embedding the wire. Applying heat for short periods at intermittent locations is presented as a solution to this problem while still melting the plastic enough to produce the bonding necessary for the wire to be embedded into the previous printed layer of plastic substrate. This technique is then used to manufacture a pair of identical parts, each with an embedded antenna intended for wireless power transfer. Once the first layer of wire antenna is embedded, additional layers of plastic are deposited to embed the copper wire completely within the part. Four separate embedded antenna layers of embedded wire are connected to create a multi layered, multi coil antenna in two identical parts. Experiments were then run to prove the viability of wireless power transfer from one part to the other.

Modular Multilevel Converter With Embedded Energy Storage for Bidirectional Fault Isolation

Modular multilevel converter (MMC) has been widely used in the multi-terminal overhead line high-voltage direct current (HVDC) system due to its outstanding performance. However, the AC side and the DC side of MMC-HVDC have a strong interaction and will be affected by each other's faults, which brings the risk of system instability. In this paper, a modified MMC named active MMC with embedded energy storage in submodules (SMs) is proposed to isolate the impact of faults as a firewall. Firstly, the topologies of the active MMC and SMs with energy storage are introduced. Then the operation principle of the active MMC under different faults is analyzed in a multi-terminal MMC-HVDC system. Thirdly, the complete control scheme of the active MMC is proposed for bidirectional fault isolation. Finally, two main application scenarios of the active MMC are simulated in a three-terminal MMC-HVDC system and a particularly designed AC/DC hybrid transmission system respectively in PSCAD/EMTDC. The simulation waveforms of the active MMC are compared with the conventional MMC. Simulation results show that the active MMC can effectively protect the AC system and DC system from each other's faults.

The Role of Renewable Energy in Regional Energy Transitions: An Aggregate Qualitative Analysis for the Partner Regions Bavaria, Georgia, Québec, São Paulo, Shandong, Upper Austria, and Western Cape

The study aims to identify the strengths, weaknesses, opportunities, and threats (SWOT) of renewable energy deployment in regional energy transitions for the regions of Bavaria, Georgia, Québec, São Paulo, Shandong, Upper Austria, and Western Cape, which comprise a political and scientific network called the Regional Leaders’ Summit (RLS) and RLS-Sciences, respectively. The results classify current renewable energy usage for electricity, heat and fuel production, existing renewable energy potentials, sound legal frameworks to support renewable energy, ongoing research and development activities and expertise in renewable energy conversion and storage as strengths. That fossil fuels still hold a significant share in gross inland energy consumption, energy-intensive industrial structures continue to be supported by fossil fuels and grid access is limited for renewables are identified as weaknesses. The main opportunities are green economies, climate change mitigation and technological innovations. Associated threats are demographic developments, lack of social acceptance and renewable energy resource volatility. We conclude that these regions’ energy systems could potentially enable the realization of a strong integration of renewables and cover partially distributed, decentralized energy systems with embedded energy storage, and the application of smart technologies. Furthermore, we discover that the role of governments in guiding and managing regional energy transitions is highly important.

Optimal Energy Efficiency Tracking in the Energy-Stored Quasi-Z-Source Inverter

In this paper, the interaction between the energy storage (ES) power distribution and system efficiency enhancement is researched based on the energy stored quasi-Z-source inverter. The corresponding current counteraction, stress reduction, power loss profile, and efficiency enhancement around the embedded energy storage units are studied in details. Firstly, the current counteraction effect on the device current is presented with the embedded ES source. The corresponding reduction in the device current stress is revealed. Then, the detailed device power loss expressions with current redistribution in the impedance network are explored mathematically. A quasi-inverted-trapezoidal power loss profile is found with the embedded source power distribution. To further increase the overall system efficiency, an optimal energy efficiency tracking strategy is proposed for the ES-qZSI (energy-stored quasi-Z-source inverter) based on the power distribution control. Both the simulation and the experiment verified that the power loss is reduced by over 40% through the proposed efficiency enhancement method. The device current and loss analysis for the embedding of energy storage can also be extended to the operating range optimization in other ES systems.

Enhanced Dielectric Permittivity of Optimized Surface Modified of Barium Titanate Nanocomposites.

High permittivity polymer-ceramic nanocomposite dielectric films take advantage of the ease of flexibility in processing of polymers and the functionality of electroactive ceramic fillers. Hence, films like these may be applied to embedded energy storage devices for printed circuit electrical boards. However, the incompatibility of the hydrophilic ceramic filler and hydrophobic epoxy limit the filler concentration and therefore, dielectric permittivity of these materials. Traditionally, surfactants and core-shell processing of ceramic fillers are used to achieve electrostatic and steric stabilization for adequate ceramic particle distribution but, questions regarding these processes still remain. The purpose of this work is to understand the role of surfactant concentration ceramic particle surface morphology, and composite dielectric permittivity and conductivity. A comprehensive study of barium titanate-based epoxy nanocomposites was performed. Ethanol and 3-glycidyloxypropyltrimethoxysilan surface treatments were performed, where the best reduction in particle agglomeration, highest value of permittivity and the lowest value of loss were observed. The results demonstrate that optimization of coupling agent may lead to superior permittivity values and diminished losses that are ~2–3 times that of composites with non-optimized and traditional surfactant treatments.

Power flow management controller within a grid connected photovoltaic based active generator as a finite state machine using hierarchical approach with droop characteristics

Grid integration of photovoltaic (PV) system with a hybrid energy storage can help not only in increasing more penetration of PV system into the network but also in improving the power system dynamics and control in addition to helping the demand side management. In this work, a PV system with a hybrid energy storage including a battery array and a super capacitor bank is going to work as an active generator with innovative load management and power flow control strategies for managing the active power demand locally considering the grid constraints. This work proposes an architecture for a PV based active generator, which can provide active power in controlled manner while maintaining the frequency stability within the power grid. With the proposed architecture and innovative control strategies, the load demand to the grid can be effectively reduced as the PV generated power can be maximally utilized locally and the power fluctuations can be compensated using the embedded energy storage. The power flow is managed using the hierarchical approach with the state-flow and droop characteristics as a finite state machine.

Non-Gaussian Residual Based Short Term Load Forecast Adjustment for Distribution Feeders

The evolving role for electricity network operators means that load forecasting at the distribution level has become increasingly important, presenting the need for anticipation of the behavior of highly dynamic and diversely distributed loads. The commonly held assumption of Gaussian residuals in forecasting does not always hold for distribution network loads, increasing the uncertainty in balancing a system at this network level. To reduce the operational impact of forecast errors, this paper utilizes different multivariate joint probability distributions to capture the intra-day dependency structure of forecast residuals. Transforming these to the conditional form enables forecast corrections to be made at variable horizons even in the absence of the forecast model. Improvements in accuracy are demonstrated on benchmark load forecast models at distribution level low voltage substations. A practical distribution system application on scheduling embedded energy storage shows substantial reductions in grid imports and hence costs to distribution level customers from utilizing the proposed intraday correction approach.

An effective hybrid wind-photovoltaic system including battery energy storage with reducing control loops and omitting PV converter

Abstract In this paper, an effective hybrid wind-photovoltaic system including battery energy storage system with an optimal number of converters has been introduced. The proposed system provides an economical solution for combining PV and grid by removing the PV dedicated converter. The proposed configuration uses both the grid side and rotor side converters of the generator to inject PV power into the grid. So, it is also able to inject PV power into the network more efficiently compared with the conventional systems. The complementary profiles of solar radiation and wind energy considerably improves the converters utilization. Moreover, by means of the embedded energy storage, the impact of intermittency of wind and radiation has been significantly reduced in the proposed system. Additionally, even though the converter typically dedicated to PV systems has been dispensed with, the PV system operates with a maximum power point tracking (MPPT) strategy. The simulation results verify the ability and effectiveness of the proposed system in comparison with a previously proposed similar system.

Polymer composites: Evolve towards multifunctionality or perish

Polymer composites were initially adopted and became popular in transportation sectors (primarily and massively in aerospace, then automotive and in a lesser extent railway industry) to manufacture structural and semi-structural parts driven by their superior strength and stiffness-to-weight ratio. Such market segments, where the lighter is the better, used to be the Eldorado of textile-reinforced polymers. However emerging metal alloys and new lightweight designs allowed by additive manufacturing are likely to threaten traditional polymer composite solutions, all the more so given that their recycling remains a tricky issue. Thus, polymer composites are destined to evolve to remain attractive and competitive. Lightweighting is no longer enough to win the race, multifunctionality becomes a crucial asset. The ability to add functionality to a composite part is nowadays significant for the performance and added-value of structural components. Self-healing, embedding sensors and actuators for structural health monitoring and adaptive response, embedded energy storage and energy harvesting, enhancement of thermal and electrical conductivity, and data-transmission within composite parts are some examples of the challenges to face. To re-invent this class of materials, one can take advantage of new manufacturing processes (robotic automation, process hybridisation, 3D-textile reinforcement, direct composites 3D printing) and new materials – incorporating for instance nanocarbon (graphene, carbon nanotubes), metallized fibres or electroactive/conductive/piezoelectric polymer matrices into composites. Novel versatile and scalable additive manufacturing 3D printers, dedicated to the production of thermoplastic composite parts and having unprecedented features, are currently developed for this purpose. They are based on multi-axis robots mounted on translation rails and equipped with several extruders permitting multi-materials processing; fed by standard polymer pellets, they offer great flexibility (simultaneous deposition of several thermoplastics, chopped fibre-reinforced and filled plastics, embedding of continuous fibres and possibly linear sensors) and allow manufacturing of several meters long/large components. Competition between materials is ever tougher. Collaborations between academic and industrial players are the key to develop innovative solutions meeting the demand for composite solutions allying design freedom, lightweight, high multifunctional performance and cost-efficiency.

Probabilistic Voltage Management Using OLTC and dSTATCOM in Distribution Networks

Low-voltage (LV) feeder voltage magnitude and unbalance are often the constraining factors on a feeder's capacity to absorb rooftop photovoltaic (PV) generation. This paper presents a new probabilistic method for voltage management in distribution networks through the placement of distribution static compensators (dSTATCOMs) and on-load tap changers (OLTCs) considering the reactive capability of PV inverters in multiple LV and medium-voltage distribution networks. The method uses a modified particle swarm optimization. In this paper, several scenarios for the placements of multiple dSTATCOMs with and without embedded energy storage systems using both reactive and real power compensation are investigated in combination with an OLTC equipped with independent per-phase tap-changing control. The voltage constraints in the proposed method are statistically defined using three duration curves. These are the voltage unbalance, maximum voltage, and minimum voltage duration curves. The method is comprehensively tested for varying load and PV generation based on data from a real Australian distribution network with considerable unbalance and distributed PV generation. The results show that PV hosting capacity increases where the proposed approach is applied.