Flywheel Energy Storage Research Articles

Design and Evaluation of 5-DOF Magnetic Bearing System for Saucer-shaped Flywheel Battery

Design and Evaluation of 5-DOF Magnetic Bearing System for Saucer-shaped Flywheel Battery

ОБРАТИМЫЙ ПРЕОБРАЗОВАТЕЛЬ ЭНЕРГИИ С МАХОВИЧНЫМ НАКОПИТЕЛЕМ В СИСТЕМАХ ЭЛЕКТРОСНАБЖЕНИЯ

The problem of voltage unbalance and the need to power factor correction remain a relevant objective for electric power engineering. A variable load profile reduces the operating efficiency of electric power plants and leads to an overestimation of the power of transformer substations and the wire size of supply lines. Thus residential buildings power equipment remains underloaded for a significant part of the time. The decrease of power-frequency characteristic is becoming increasingly noticeable. This situation is not a problem yet, but in the future it may complicate the task of frequency stabilization. Finding solutions to existing and predicted problems is an important topic of research. To solve the problems posed, the work proposes the concept of a reversible energy converter, that is an electrotechnical complex with a flywheel energy storage and a two-section frequency converter based on two reversible voltage converters (active front end). The planning area of application of a reversible energy converter is transformer substations of residential and public buildings of urban power supply systems. The reversible energy converter is designed to solve such problems as load leveling, reactive power compensation (power factor correction), balancing voltages and power-frequency characteristic control. The work presents a connection scheme a reversible energy converter to the supply system and provides an expression for the phase load voltage.

Multiphysics Analysis of Flywheel Energy Storage System Based on Cup Winding Permanent Magnet Synchronous Machine

Multiphysics Analysis of Flywheel Energy Storage System Based on Cup Winding Permanent Magnet Synchronous Machine

Integration of storage technology oversight: power system and computer engineering analogy

Energy storage, analogous to data storage in a computer system, is one of the enabling technologies that has emerged alongside the widespread use of renewable energy sources in the nation's power grid. This article shows that the underlying platforms for storing data and energy are quite similar. Batteries and hydrogen storage offer significant energy potential, much like a hard disk for storing vast amounts of data in a computer's central processing unit (CPU). A supercapacitor or flywheel storage device can be used to have emergency power on hand, with access times as fast as random access memory (RAM) in modern computers. In this study, we propose an energy-control scheme for caches that is akin to computer engineering and is used to coordinate the operation of multilevel storage systems that incorporate both capacity and access-oriented storage. By supporting the energy-management system, which in turn provides modern plug-and-play functionality, cache energy control helps optimise the system as a whole. Such an integrated system calls for renewable energy generation, local loads, fueling stations, and connections to gas and electric distribution grids. Distribution energy concepts with various storage systems can be easily grasped by drawing parallels between computer engineering and power system integration.

Improved Gorilla Troops Optimizer-Based Fuzzy PD-(1+PI) Controller for Frequency Regulation of Smart Grid under Symmetry and Cyber Attacks

In a smart grid (SG) system with load uncertainties and the integration of variable solar and wind energies, an effective frequency control strategy is necessary for generation and load balancing. Cyberattacks are emerging threats, and SG systems are typical cyber-attack targets. This work suggests an improved gorilla troops optimizer (iGTO)-based fuzzy PD-(1+PI) (FPD-(1+PI)) structure for the frequency control of an SG system. The SG contains a diesel engine generator (DEG), renewable sources like wind turbine generators(WTGs), solar photovoltaic (PV), and storage elements such as flywheel energy storage systems (FESSs) and battery energy storage systems (BESSs) in conjunction with electric vehicles (EVs). Initially, the dominance of the projected iGTO over the gorilla troops optimizer (GTO) and some recently suggested optimization algorithms are demonstrated by considering benchmark test functions. In the next step, a traditional PID controller is used, and the efficacy of the GTO method is compared with that of the GTO, particle swarm optimization (PSO), and genetic algorithm (GA) methods. In the next stage, the superiority of the proposed FPD-(1+PI) structure over fuzzy PID (FPID) and PID structures is demonstrated under various symmetry operating conditions as well as under different cyberattacks, leading to a denial of service (DoS) and delay in signal transmission.

Research on control strategy of flywheel energy storage system based on active disturbance rejection control

The flywheel energy storage system (FESS) has been attracting the attention of national and international academicians gradually with its benefits such as high energy power density, high conversion productivity, and inexpensive pollution. For the mutual limitation problem of reaction speed and overshoot of the conventional PI controller, it is hard to satisfy the demand of high efficiency control. In this study, the Active Disturbance Rejection Controller (ADRC) is adopted to substitute the classical PI controller in the flywheel energy storage control system. The control system of an external loop of speed and an internal loop of current is adopted at the motor side. The standard ADRC is adopted by increasing the new nonlinear control function. The control system adopted the control strategy of the DC bus voltage external loop and the current internal loop on the grid side, as well as the second-order Linear Active Disturbance Rejection Controller (LADRC), to enhance the control ability of the DC bus voltage. In the charge/discharge control of the FESS, both the velocity external loop and current internal loop control strategies are utilized to simplify the system structure. The performance shows that the improved control system could effectively enhance the charging and discharging speed of the FESS and effectively suppress the DC bus voltage rise caused by flywheel state switching so that the system has better robustness.

Vibration Characteristics and Vibration Mitigation Analysis of End Cap PM Excitation Homopolar Inductor Machine

Vibration analysis and vibration mitigation are very important to ensure the safe and stable operation of electrical machines applied in flywheel energy storage systems (FESS). In traditional integer slot synchronous machines, it is generally believed that there is only the zeroth-mode vibration caused by odd tooth harmonics. However, the homopolar inductor machine (HIM) adopts the end cap excitation structure, which makes its air-gap magnetic field contain the DC component, odd tooth harmonics and even tooth harmonics. The force density distribution on the slotted stator is analyzed by the magnetomotive force-multiplying permeance method. The results show that there are both zeroth- and pth(pole pairs)-mode vibrations caused by tooth harmonics and DC component of the air-gap flux density. Furthermore, to reduce vibration and resonance, and to improve the electromagnetic performance of HIM, it is best to use the stator skew slot, the magnetic slot wedge (MSW) and the sinusoidal rotor slot at the same time. Finally, a 54-slot/6-pole EPE-HIM is tested to validate the analytical and the finite-element method (FEM) results, and the variation trend of the experimental results and FEM results is the same.

Analysis of the Amount of Flux Variation on the HTS Surface by the Oscillation of HTS Magnetic Bearing Rotor

Magnetic bearing is used in flywheel energy storage system and can address energy loss at contact points in rotating because a rotor can be supported without contact points. However, in order to keep a rotor levitating, a control system is required. The HTS magnetic bearing levitates the rotor by pinning force without a control system and of a rotor including permanent magnets and a HTS. The vertical oscillation of the rotor is suppressed because the flux is interlinked to the outside of the HTS. Therefore, the rotor oscillates in the horizontal direction in rotating. This oscillation generates the flux variation on the HTS surface and it decreases the number of revolutions. This paper proposes an analysis of flux variation on the HTS surface by the oscillation of HTS magnetic bearing rotor. The effect of the oscillation of the rotor on the number of revolutions is shown by the analysis of the flux variation of the HTS. In the analysis results, the amount of flux variation increased rapidly because the rotor increases the oscillation. The flux variation causes a decrease the in number of revolutions and the small oscillations cause flux variation on the HTS surface. However, the decrease in the number of revolutions is small because the amount of the flux variation is small.

Integrated Optimal Energy Management and Sizing of Hybrid Battery/Flywheel Energy Storage for Electric Vehicles

This paper presents an integrated optimal Energy Management Strategy (EMS) and sizing of a high-speed Flywheel Energy Storage System (FESS) in a battery electric vehicle (EV). The methodology aims at extending the battery cycle life and drive range by relegating fast dynamics of the power demand to the FESS. For the EMS, the battery power and FESS energy are considered as weighted objectives of an optimization problem that are established using Pontryagin's Minimum Principle (PMP). In order to derive the optimal FESS size, the sizing algorithm is targeted to minimize the battery degradation level and increase the FESS energy interaction with the system. The performance of the proposed methodology is assessed using some driving cycles including ECE-15, UDDC, HWFET, and US06. Comparing the proposed battery/FESS to the battery-only topology, the battery SoH and life cycle are improved considerably for different driving cycles.

Augmented Lagrangian approach for multi-objective topology optimization of energy storage flywheels with local stress constraints

Augmented Lagrangian approach for multi-objective topology optimization of energy storage flywheels with local stress constraints

Permanent Magnet Motors in Energy Storage Flywheels

Flywheel energy storage system stores energy in the form of mechanical energy and can convert mechanical energy into electrical energy. Flywheel energy storage is a mechanical energy storage system. Due to its high energy storage density, high power, high efficiency, long life, no pollution and other characteristics, it has a broad application prospect in the field of aerospace, power peaking, UPS, electric vehicles, high-power electromagnetic guns and so on. With the continuous development of magnetic levitation, composite materials, vacuum and other technologies, the current flywheel energy storage technology is mainly through the increase in the speed of the flywheel rotor to achieve energy storage, the continuous development of various technologies, so that the research of flywheel energy storage technology has stepped into the "high-speed" development period, and has been widely used in many fields. Application, and gradually become the focus of research in various countries.

Hybrid energy storage power allocation strategy based on parameter-optimized VMD algorithm for marine micro gas turbine power system

The power system onboard ships is typically a low-inertia, small-capacity isolated grid that is highly susceptible to system disturbances and instability, especially when connected to high power pulse loads. To mitigate power fluctuations and ensure stable operation, a hybrid energy storage system (HESS), which comprises the battery system and flywheel energy storage devices, has emerged as a promising solution. This paper explores the control strategy and coordinated operation of marine gas turbine power generation systems operating under pulse load conditions and presents a novel hybrid energy storage power allocation strategy based on variational mode decomposition (VMD). Specifically, we propose to implement parameter optimization of VMD using an artificial hummingbird algorithm (AHA), which enables effective primary allocation of hybrid energy storage power. To achieve secondary power allocation, we design two fuzzy controllers to optimize the state of charge (SOC) of battery system and speed of flywheel device. To evaluate the feasibility and effectiveness of the proposed control strategy, we establish a theoretical model of a shipboard micro gas turbine (MGT) direct current (DC) power system, which includes an MGT, generator, HESS, and pulse power load. Our simulation results demonstrate that the artificial hummingbird algorithm outperforms the particle swarm algorithm concerning search speed and calculation accuracy for parameter optimization of variational mode decomposition. Moreover, the proposed parameter-optimized VMD method can adaptively decompose pulse load power fluctuations and achieve optimal allocation of the flywheel and battery power in the HESS. Finally, the parallel fuzzy controller design effectively optimizes the operation ranges of the flywheel device and battery system, prevents over-charging and over-discharging of energy storage equipment, ensures that the SOC of energy storage equipment remains within a fixed interval, and reduces frequent and high-power charging and discharging of batteries.

Research on frequency modulation capacity configuration and control strategy of multiple energy storage auxiliary thermal power unit

The rapid development of new energy sources has had an enormous impact on the existing power grid structure to support the “dual carbon” goal and the construction of a new type of power system, make thermal power units better cope with the impact on the original grid structure under the background of the rapid development of new energy sources, promote the consumption of new energy sources such as solar and wind energy, and further expand the channels for upgrading and flexibility transformation of thermal power energy storage, improve the stability, safety and economy of thermal power unit operation. Therefore, based on the research status at home and abroad, a hybrid energy storage system is added to solve the above problems. The lithium battery-flywheel control strategy and the regional dynamic primary frequency modulation model of thermal power units are proposed, and study the capacity configuration scheme of flywheel‑lithium battery hybrid energy storage system under a certain energy storage capacity, the frequency modulation performance is evaluated by the system frequency fluctuation degree, fluctuation peak range and other indicators. Study under a certain energy storage capacity thermal power unit coupling hybrid energy storage system to participate in a frequency modulation of the optimal capacity configuration scheme, and perform simulation verification using MATLAB/Simulink. When the thermal power unit is coupled with a 10.8612 MW/2.7151 MWh flywheel energy storage system and a 4.1378 MW/16.5491 MWh lithium battery energy storage system, while adaptive variable coefficient droop control is adopted, the system frequency range is 0.00328 p.u.Hz, and the fluctuation degree of the output power of the thermal power units is 0.00498 p.u.MW, compared to the individual frequency regulation of thermal power units, it reduces 52.07 % and. The results show that when the thermal power unit is disturbed by external load, hybrid energy storage assisted thermal power unit frequency modulation reduces the mechanical loss of thermal power unit to a certain extent and extends the service life of the unit, effectively improve the operation stability and economy of thermal power units, further reduce the phenomenon of abandoning wind and light, and better promote the utilization of new energy.

Review of ancillary services and optimal sizing of an energy storage system in a microgrid

The rapid growth of distributed energy generation has brought new challenges for the management and operation of power systems. Voltage fluctuation is one of the primary factors preventing further photovoltaic (PV) penetration in low-voltage networks. The proper sizing and location of any storage system are essential for reducing costs and eliminating losses, which is another element. This review presents an in-depth overview of the different ancillary services that storage systems may offer and a proper sizing of energy storage systems (ESS). Different kinds of ESSs store energy in different ways. Some of these have reached their full potential, while others are still being worked on. Specific storage solutions may be picked depending on how well the application needs to run. Pumped-hydro and thermal energy storage systems are best for large-scale energy storage, while battery energy storage systems are highly suggested for high power and energy needs. Most of the time, supercapacitors, superconducting magnetic energy storage (SMES), and flywheel energy storage (FES) are used for short-term and fast-response uses. Hydrogen and methane are not often used to store energy because they could be more efficient. A few case studies are also given.

Dawn of clean energy: Enhanced heat transfer, radiative cooling, and firecracker-style controlled nuclear fusion power generation system

Global climate change has become a major environmental threat and development challenge facing humanity. Controllable nuclear fusion is a globally recognized ideal solution for clean energy, but its required high-energy triggering conditions and intense energy release prevent existing technologies from achieving safe, stable, and long-term continuous operation. Here, inspired by the traditional Chinese firecrackers, we propose a pulsed fusion reaction flywheel energy storage multi-reactor relay operation to drive the steam turbine to continuously and stably generate electricity for a long period of time; meanwhile, to install cleaning rotors in the cooling medium pipeline to enhance heat exchange, and to apply radiative cooling technology on the surface of the cooling tower to improve cooling efficiency and to reduce energy consumption, thereby improving system safety and overall energy efficiency. Proposing the combination of original technologies at both the hot end and the cold end of the system, we strive to open up a new way for controllable nuclear fusion power generation.

Assessment of photovoltaic powered flywheel energy storage system for power generation and conditioning

Energy storage and power conditioning are the two major issues related to renewable energy-based power generation and utilisation. This work discusses an energy storage option for a short-term power requirement, which also acts as a power conditioner. The flywheel, an old invention, is included in the electrical power generation arrangement to achieve energy storage and power conditioning requirements. A Photovoltaic solar system is used as a primary source from which the required DC voltage is obtained through an SPWM-based DC-DC converter. This power is fed to an arrangement consisting of a BLDC machine as prime mover, which drives a mass of flywheel. An alternator connected with the motor and flywheel to supply a 1000 W load. The flywheel is designed to take care of the dynamic stability assisted by a suitably designed controller unit and supporting power supply units t ensure the system's reliability. Hence a conditioned and reliable power supply is provided to the load. This research aims to decide on the dimensions and material of the flywheel to be used, which was achieved using ANSYS. Two different materials were selected, and stress analysis was done to ensure their suitability as an energy storage medium in the power generation system. Similarly, the converters and controllers were simulated using MATLAB to fit them to the renewable power generation scheme based on which a working model is fabricated, and tested through proper commissioning, to get the aimed objectives. The outcome of simulation and experimentation were compared, and suitable illustrations were given to prove the successful implementation of a flywheel-based energy storage system.

ADRC‐based control strategy for DC‐link voltage of flywheel energy storage system

AbstractThe direct current (DC)‐link voltage control of the flywheel energy storage system plays an important role in realizing high‐quality grid connection. With the traditional proportional‐integral control, the DC‐link voltage cannot track its reference value quickly and smoothly when the flywheel energy storage system switches from the charging stage to other working stages. Therefore, a DC‐link voltage control strategy for the flywheel energy storage system based on active disturbance rejection control is proposed in this paper to deal with this issue. The DC‐link voltage and its differential value are considered as the state variables in this strategy. The internal and external disturbances, such as load power, switching loss, and parameter uncertainty, are regarded as an expanded state. By inputting the voltage error and the observed disturbance into the nonlinear state feedback control law, the rapidity and anti‐interference of the DC‐link voltage control are ensured under different States of Charge of the flywheel energy storage system. Then, the coefficient freezing method is used to analyze the effects of the disturbance observation bandwidth by nonlinear gain and pole position changes. The DC‐link voltage can track the reference value over a wider frequency range of disturbances. By configuring the appropriate observer structure parameters, the disturbance observation bandwidth under the nonlinear function gain variation is always higher than the expected bandwidth. The effectiveness of the proposed control strategy is verified by simulation results at last.

A Novel Magnetic Suspension Flywheel Battery with a Multi-Function Air Gap

In this study, a novel magnetic suspension flywheel battery with a multi-function air gap is proposed. Based on the unique multi-function air gap, the degrees of freedom between the control magnetic circuits can be independent of each other, reducing the coupling effect between degrees of freedom. The proposed flywheel battery system topology inherits the unique advantages of the magnetic suspension flywheel battery. However, due to the breakthrough of the overall topology in the air gap, flywheel, and protection measures, the system has more advantages in the precise design of the magnetic circuit, decoupling, high-stability control, and energy storage. First, the advantages, geometric characteristics, and magnetic circuit of the flywheel battery system are introduced and analyzed. Then, the position and length of the multi-function air gap and conventional air gap in the magnetic circuit are optimized to ensure the best magnetic performance of the entire magnetic circuit. Then, the flywheel, motor, and protection settings are introduced in detail. Finally, performance tests are conducted, and the good experimental results show that the proposed flywheel battery has good anti-interference ability and decoupling ability.

A multi‐area design of under frequency load shedding schemes considering energy storage system

AbstractThis paper presents a comprehensive under frequency load shedding (UFLS) model that can be implemented in a multi‐area power system with real network characteristics. Conventional single‐area UFLS models operate on the basis of an equivalent center‐of‐inertia (COI) model, which ignores the local dynamics of system frequency response (SFR) and the impacts of load shedding location. Unlike the single‐SFR model, that is commonly utilized in previous works, the suggested multi‐area or multi‐SFR UFLS plan of this research has the distinct benefit of taking into account the dynamics of power transfer across different electric areas. The proposed multi‐area UFLS design incorporates a flywheel energy storage system (FESS) to support the inertial system frequency response and alleviate more than 30% load shedding while improving the frequency nadir by 25%. In order to investigate the performance of the proposed method under high penetrations of inertia‐free renewables, the inertia of the power network is reduced by around 30%; therefore the proposed UFLS scheme is assessed under a low inertia scenario. The proposed multi‐stage UFLS scheme is formulated as a mixed‐integer linear programming problem, and the optimal settings, including frequency set‐points and load shedding, are then optimized. The efficiency of the proposed model is verified using the IEEE‐118 Bus dynamic test system.

Life cycle assessment of electrochemical and mechanical energy storage systems

The effect of the co-location of electrochemical and kinetic energy storage on the cradle-to-gate impacts of the storage system was studied using LCA methodology. The storage system was intended for use in the frequency containment reserve (FCR) application, considering a number of daily charge–discharge cycles in the range of 50–1000. The results show that a significant environmental benefit (up to a 96% decrease in cradle-to-gate global warming potential, from 1.65 ± 0.12 to 0.059 ± 0.004 kg CO2-eq./kWh) can be obtained by the co-location of battery and flywheel storage systems, owing to the ability of the flywheel component to preserve battery lifetime by delivering the frequent charge events required in the FCR application. A moderate saving of 24% in global warming potential (from 1.65 ± 0.12 to 1.26 ± 0.11 kg CO2-eq./kWh) could already be achieved by switching from a battery to flywheel storage system with repeated charge–discharge cycling (200 or more charge events per day). This study highlights the need to consider the intensity of charge–discharge cycling when choosing an environmentally preferable storage technology as well as introducing a methodology for incorporating the number of daily cycles in the analysis.