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As the renewable energy sources (RES) production is strongly influenced by multiple geographic factors and highly variable, the need for both energy storage integration and robust real-time power management strategies development is obvious. Wind power represents the largest generating capacity among RES, being at the same time the most fluctuant. The capability to overcome the great disadvantage of wind power variability supports rising its penetration while preserving current operation modes of power systems, so new fashions to achieve this target are of great interest. This paper aims to prove the robustness of a recently introduced power management strategy, able to operate in online conditions, based on simultaneous perturbation stochastic approximation (SPSA) algorithm. To this regard, two different real datasets for wind power profiles with different statistical features are employed. The power management strategy is implemented on a hybrid energy storage system comprising a battery and a flywheel, modeled in Simulink/Matlab. The objectives of the proposed strategy are to reduce the instantaneous power ramp of the profile injected to the grid while smoothening the power profile exchanged by the battery in order to preserve it. Simulations are performed in representative conditions selected on statistical basis. It is demonstrated that the SPSA based power management achieves similar performances in all simulation conditions, proving to be robust. As a performance indicator, the reduction of the power ramp in reference to the 90% CDF threshold is evaluated. It is remarked as an 80% power ramp reduction is obtained towards the grid in both sites. Moreover, the further target is achieved in terms of battery lifetime extension; specifically, the fluctuation of the power profile exchanged by the battery is smoothed by 63% in the first site and 48% in the second, with respect to the flywheel one.

The popularity of the eBus has been increasing rapidly in recent years due to its low greenhouse gases (GHG) emissions and its low dependence on fossil fuels. This incremental use of the eBus increases the burden to the power grid for its charging. Charging eBus requires a high amount of power for a feasible amount of time. Therefore, developing a fast-charging station (FCS) integrated with Micro Energy Grid (MEG) and hybrid energy storage is crucial for charging eBuses. This paper presents a design of FCS for eBus that integrates MEG with hybrid energy storage with the energy management system. To reduce the dependency on the main utility grid, a hybrid micro energy grid based on a renewable source (i.e., PV) have been included. In addition, hybrid energy storage of batteries and flywheels has also been developed to mitigate the power demand of the fast-charging station during peak time. Furthermore, a multiple-input DC-DC converter has been developed for managing the DC power transfer between the common DC bus and the multiple energy sources. Finally, an energy management system and the controller has been designed to achieve an extensive performance from the fast charging station. MATLAB Simulink has been used for the simulation work of the overall design. Different test case scenarios are tested for evaluating the performance parameters of the proposed FCS and also for evaluating its performance.

This paper presents a comparison of two methods to represent variable blade inertia in two codes for aero-servo-elastic simulations of wind turbines: the nonlinear aeroelastic multi-body model HAWC2 and the nonlinear geometrically exact beam model BeamDyn for OpenFAST. The main goal is to enable these tools to simulate the dynamic behavior of a wind turbine with variable blade inertia. However, current state-of-the-art load simulation tools for wind turbines cannot simulate variable blade inertia, so the source code of these tools must be modified. The validity of the modified codes is proven based on a simple beam model. The validation shows very good agreement between the modified codes of HAWC2, BeamDyn and an analytical calculation. The add-on of variable blade inertias is applied to reduce the mechanical loads of a 5-megawatt reference wind turbine with an integrated hydraulic-pneumatic flywheel in its rotor blades.

Flywheels are nowadays a solution for the dynamic charging of electric vehicles since they act as transient energy storage. The need for a top efficient reversible power converter for the flywheel system is crucial to assure high dynamic performance. The paper presents the design of a 50 kW highly efficient reversible three-phase DC–AC inverter involving the most recent silicon carbide metal oxide semiconductor field effect transistors, and its experimental validation on a home-made emulator. Highest efficiency in reversible mode, compactness, and thermal enhancement are the targeted objectives that have been achieved. The power converter prototype evaluated on an original pulse width modulation testing-bench is able to emulate the working of the flywheel system. High frequency pulse width modulation switching, speed cycle operating, and thermal losses are evaluated. In addition, an efficiency above 99% for the converter has been attained, enabling robust functioning of the flywheel system emulator to perform specific charging profiles for electric vehicles.

In this study, we developed a superconducting magnetic bearing using a permanent repulsive magnet. A repulsive magnetic levitation system with a permanent magnet can generate a strong levitation force in the absence of a power supply. However, it is unstable, except in the direction of repulsion. In contrast, superconducting magnetic bearings can generate a restoring force in all directions by utilizing the magnetic flux pinning property of the superconductors. Therefore, we constructed a superconducting magnetic bearing (SMB), which is stable along all axes without control, and has a strong axial levitation force, by combining a repulsive-type magnetic levitation system and a superconducting magnetic levitation system. We also reduced the amount of HTS used for the SMB and proposed an efficient method of using HTS. Furthermore, a driving test of the flywheel incorporating the SMB was conducted to verify the characteristics of the SMB. The experiment confirmed that the flywheel could overcome the resonance and drive the flywheel. In the drive experiment, the flywheel was driven up to 10,000 rpm. [ABSTRACT FROM AUTHOR]

Copyright of Southern Energy Construction is the property of Southern Energy Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As the key mechanism of attitude control of micro/nano-satellites, the flywheel design is mostly based on empirical formulae that do not meet the requirements of lightweight and high-performance micro/nano-satellite platforms. In this paper, the structural shape of micro/nano-satellite flywheels is analysed, and a set of flywheel optimisation methods is proposed to realise the parametric optimisation analysis of the structural shape. First, the general principle of flywheel efficiency is introduced, the optimisation evaluation factor of flywheel design is proposed, and the parametric model of a flywheel structure is established by using the finite element secondary development technology, which can be used to quickly build a finite element model of different dimensions. Second, the optimisation model of flywheels is established while introducing the approximate model algorithm, greatly improving the optimisation efficiency. Considering the phenomenon that the genetic algorithm falls below local optimisation under a large parameter range, the method of initial optimisation is proposed to reduce the upper and lower limits of the optimisation parameters. Finally, the optimal shape of the flywheel is obtained by using the parametric optimisation model of the flywheel. The finite element analysis results show that the flywheel optimisation evaluation factor proposed in this work can effectively improve the comprehensive performance of the flywheel as the optimisation target, and the corresponding optimisation method can be well applied to the engineering application and design of micro/nano-satellite platforms. This can help guide the structural optimisation design of micro/nano-satellite platforms in the future. [ABSTRACT FROM AUTHOR]

The high efficiency of the flywheel hybrid powertrain, as well as its power characteristics, can help to meet high energy/power conversion needs, which may prove to be promising. Moreover, the flywheel hybrid powertrain may reduce dependence on batteries. This paper presents the EC-BERS in order to capture more mechanical power than its rated power, and to reduce the charge/discharge cycles of the battery. In this new energy recovery system, maximum torque can be obtained in the higher speed zone, leading to two marked improvements in terms of improving the braking efficiency. The working point of the system changes and shifts to the high-speed zone to meet the maximum torque at higher speeds. Furthermore, this powertrain can transfer the vehicle kinetic energy into the flywheel directly in the same form. Only the slip energy needs to be dealt with in the electrical form, which is beneficial to prolonging the battery life. Two typical systems were emulated under the same conditions to verify this feature, and a small prototype was designed to prove the concept. [ABSTRACT FROM AUTHOR]

• Propose an innovative electromagnetic seismic isolation system with flywheels. • The EMSIS-FW can easily and simultaneously adjust both its frequency and damping. • Inertance can replace actual mass to reduce earthquake-induced forces. • Perform shaking table tests on a large-scale EMSIS-FW under near-fault earthquakes. • Develop a model to accurately predict the seismic behavior of the EMSIS-FW. Protecting seismic isolated equipment or buildings in a near-fault area is challenging because of the strong long-period velocity components of near-fault ground motions. These long-period pulses can cause excessive base displacement of conventional seismic isolation systems. In this study, an electromagnetic seismic isolation system with flywheels (EMSIS-FW) was experimentally investigated to reduce the base displacement of isolation systems during near-fault earthquakes. The EMSIS-FW consists of a sliding platform and rotary electromagnetic (EM) dampers, which can provide an EM damping force. With an additional flywheel installed on each EM damper, its moment of inertia can offer a considerable inertance for the EMSIS-FW. The inertance generated by the flywheel can be hundreds of times larger than its mass. Accordingly, the isolation frequency can be adjusted using different-sized flywheels. A prototype EMSIS-FW was designed and manufactured. A theoretical model was also developed to predict its dynamic behavior. Through shaking table tests, this study provided experimental verification of the effectiveness of inertance on isolation systems subjected to near-fault ground motions. The experimental results indicate that an increase in inertance reduces the isolation displacement, but it may increase the isolation acceleration during a typical far-field ground motion. In addition, the accuracy of the theoretical model was verified using the shaking table test. [ABSTRACT FROM AUTHOR]

This study investigated the effect of flywheel moment of inertia (0.029, 0.061, and 0.089 kg·m2) on concentric and eccentric peak power and eccentric:concentric peak power ratio during unilateral flywheel leg curl and hip extension exercises. Moreover, the inter-session reliability of peak power was analyzed during both exercises. Twenty amateur male soccer athletes attended five visits—performing three sets of eight repetitions of either unilateral leg curl or hip extension (all three moments of inertias) during each visit. For the unilateral leg curl, there were no differences in any measure between moments of inertia (p = 0.479) but a higher eccentric than concentric peak power for all moments of inertia (p < 0.001). For the unilateral hip extension, differences between moments of inertia were reported for all measures (p < 0.05). Specifically, the lowest moment of inertia elicited the greatest concentric peak power (p = 0.022), there were no differences with the medium inertia (p = 0.391), and the greatest moment of inertia obtained the greatest eccentric peak power (p = 0.036). Peak power measures obtained acceptable to excellent reliability while the eccentric:concentric ratio reported unacceptable to good reliability for both exercises. A variety of moments of inertia can elicit high eccentric knee flexor demands during unilateral leg curls, whereas higher moments of inertia are needed to achieve an eccentric-overload in peak power during hip extensions. Different exercises may have different inertia-power relationships. Concentric and eccentric peak power measures should continue to inform training, while the eccentric:concentric ratio should not be used.

Due to low system inertia in microgrids, frequencies may vary rapidly from the nominal value, leading to the complete blackout of the system unless there is an adequate spinning reserve available for balancing the supply with the demand load. This issue of instability in microgrids under islanded operation has attracted particular attention recently. A diesel generator is considered to be an ideal spinning reserve to provide back-up power to the load along with the renewable energy source in islanded system. However, the high maintenance cost and CO2 emissions of diesel generator are detrimental factors which have inspired searches for more cost effective and cleaner technologies. The integration of an energy storage system (ESS) in islanded system along with generator not only reduces generator maintenance costs but also reduces the CO2 emissions by limiting its operating hours. This paper proposes an islanded PV hybrid microgrid system (PVHMS) utilizing flywheel energy storage systems (FESS) as an alternative to battery technology to support the PV system and meet the peak demand of a small residential town with 100 dwellings. The diesel generator is used in the islanded system as a spinning reserve to maintain the stability of the islanded system when the PV system and flywheel storage cannot meet the load demand. Results of analysis of such a system demonstrate that flywheel energy storage technology of appropriate size offers a viable solution to support the operation of the standalone PV system. Furthermore, the reduction in CO2 emissions and fuel consumption has been quantified as compared with the case with flywheel energy storage systems which means the diesel generator but always be operating.

Flywheel is an important component for the canned motor reactor coolant pump (RCP). The flywheel of horizontal canned motor reactor coolant pump (HRCP) is different from RCP's flywheel. Its clearance width or different thermal conductivity structure would affect the flow structure of flywheel clearance flow, and then affect temperature distribution of the clearance, which would further affects the life and stability of flywheel. Therefore, it is necessary to analyze the flow and heat transfer characteristics of flywheel clearance flow in detail. This paper applies a Detached Eddy Simulation (DES) method to study the flywheel clearance flow of HRCP. The results show that the DES method can capture the small-scale vortex structure in turbulence Taylor-Couette flow and then give a more refined flow field morphology. The authors further study the regularity of flywheel clearance flow with different thermal conductivity structure, and the results indicate that optimizing thermal conductivity structure can effectively reduce flywheel's temperature. The authors also investigate the heat dissipation mechanism of different flywheel clearance structures. [ABSTRACT FROM AUTHOR]

The objective of this systematic review was to examine the effectiveness of flywheel training, which allows for the replication of specific sports movements, overloading both the concentric and eccentric phases. Inclusion criteria were injury prevention outcomes; ability in terms of strength, power, sprinting, jumping and change of direction; competitive athletes; and RCTs. Exclusion criteria were a lack of a control group and lack of baseline and/or follow-up data. The databases used were Web of Science, Scopus, PubMed, Cochrane Library, and Sage. The revised Cochrane risk-of-bias tool was used to assess the quality of the selected RCTs. The Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence was used. A PICOS (participants, intervention, comparators, study outcomes, and study design) approach was used to evaluate eligibility. A total of 21 RCTs with 8 to 54 participants in each study analyzed flywheel technology and its application in nine sports. The results showed that flywheel training is a good strategy to improve sports performance, providing variation in training methodologies and athletes’ adherence. Further studies are needed to define guidelines on training modality, weekly frequency, volume, and inertia load. Only a few studies have applied the flywheel device directly to overload specific multidirectional movements at different joint angles. This method is not exempt from criticalities, such as the cost and the ability to carry out only individual training.

The paper presents a sustainable electric powertrain for a transit city bus featuring an electrochemical battery-free power unit consisting of a hydrogen fuel cell stack and a kinetic energy storage system based on high-speed flywheels. A rare-earth free high-efficiency motor technology is adopted to pursue a more sustainable vehicle architecture by limiting the use of critical raw materials. A suitable dynamic energetic model of the full vehicle powertrain has been developed to investigate the feasibility of the traction system and the related energy management control strategy. The model includes losses characterisation, as a function of the load, of the main components of the powertrain by using experimental tests and literature data. The performance of the proposed solution is evaluated by simulating a vehicle mission on an urban path in real traffic conditions. Considerations about the effectiveness of the traction system are discussed. [ABSTRACT FROM AUTHOR]

Conventional implementation of slider-crank mechanisms result in high loads transmitted through the mechanical structure, inhibiting the design of compact and oil-free machines. Therefore, this research proposes to step away from the conventional, i.e., rotative, actuation and to investigate local linear actuation on the slider-component directly, while maintaining the kinematic link of the slider-crank configuration. In this work, the local linear actuating principle is evaluated experimentally where the goal is to obtain a continuous movement of the slider mechanism where Top Dead Center & Bottom Dead Center are reached and to minimize the loads transmitted through the mechanical structure. The non-isochronous transient behavior of a slider-crank mechanism loaded with a spring-damper element is detailed as well as the optimal working conditions at steady-state to achieve a reduced loading of the kinematic structure. By matching the operating frequency and resonance frequency of the system, a reduction of the loads transmitted through the system by 63% of the nominal spring load can be achieved. Further experimental (and multibody mechanical) investigation on the influence of flywheel exposes a clear trade-off between the sensitivity of the system and the transmission of the actuation force through the kinematic link. [ABSTRACT FROM AUTHOR]

Friction rings viscoelastically mounted on the arms of a flywheel to reduce vibration by functioning as friction dynamic vibration absorbers (DVAs) are proposed in this study. A design method is also proposed for the friction ring DVA under different friction models, namely Coulomb friction, tanh friction, and Stribeck friction. An equivalent nonlinear 11-degree-of-freedom (DOF) dynamic model of the flywheel with the friction ring DVA system is established to investigate the vibration reduction performance of the DVA system. A genetic algorithm is employed to determine the optimal parameters for the friction ring DVA. The harmonic balance method and the alternate frequency-/time-domain (AFT) method are used to solve the governing equations of the system and perform forced response analysis and nonlinear modal analysis. In addition, the effects of different parameters on the vibration reduction performance of the friction ring DVA are analysed. The results show that all three types of friction ring DVAs exhibit sufficiently good performance in mitigating the vibration of the flywheel. The friction ring DVAs under Coulomb friction, tanh friction, and Stribeck friction have a broad effective frequency range for vibration reduction. [ABSTRACT FROM AUTHOR]

In this article, gyroscopes and flywheels are used to prevent the rollover of a vehicle due to external forces. The rollover preventing performance of the flywheels for a heavy trailer (an inverted pendulum problem) is investigated at a high road bank angle risk. Two control moment gyroscopes (CMG) and a reaction wheel are controlled by proportional torques to keep the vehicle in a stable motion in the vertical position. The reaction wheel was used only to eliminate the dissipation energy of damper. By using the energy stored in the flywheels of gyroscopes, the sprung mass of a vehicle can make a stable oscillating motion of small amplitude, standing upright without tipping over. The optimum flywheel speed was derived from the frequency equations with the appropriate controller gain. Most importantly, the required angular momentum to keep the vehicle upright without tipping over depends on the amplitude of the gimbal oscillation and the frequency. It has also been observed that Matlab simulations of Lagrangian equations and simulations modeled in RecurDyn software are in perfect harmony. [ABSTRACT FROM AUTHOR]

Copyright of e & i Elektrotechnik und Informationstechnik is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Over the last years there have been a wide body of research exploring the best strategies to promote acute enhancements in players' performance. Despite that, most studies have been focused on adult and elite players, and different results may be identified when considering players from lower levels of performance and belonging to youth categories. In addition, most studies conducted in this domain focused in repetitive movement patterns, and while adding variability has been considered as a useful approach to enhance players' performance at short and long-term perspectives, less is known regarding it applicability to acute enhance players physical performance. Therefore, this study aimed to compare the acute enhancement effects of performing the half-squat in a flywheel ergometer between a more-repetitive approach (low noise) and a more variable approach (differential learning, high noise) in youth soccer players. Methods: A total of sixteen players (age = 16.2 ± 0.6 years) was exposed to four conditions in a randomized order: (1) repetitive intervention for 30 s; (2) repetitive intervention for 10-min; (3) differential learning intervention for 30 s; (4) differential learning intervention for 10-min. Each condition consisted in 3 sets of 6 repetitions of eccentric half squats performed in a flywheel ergometer. Countermovement jump, 10 m and 30 m linear sprint, and change-of-direction ability were measured every session at baseline (pre-test) and after each protocol (post-test). Results: No potentiation effect was observed overall with any of the interventions. In addition, no differences between protocols were found for sprinting. However, the repetitive intervention impaired jumping performance for both 30 s (small effects, p ≤.05) and 10-min intervals (small effects, p ≤.05), as well as in the change-of-direction task for 30 s (p ≤.05). Conclusions: These results may be due to the players' low experience in eccentric flywheel training. Despite these findings, individual potentiation responses emerged from both protocols when considering the individual responses, reinforcing the need to establish more personalized approaches. [ABSTRACT FROM AUTHOR]

Hydraulic transient is a flow situation where the velocity of the flow and the pressure change rapidly with time in pipes networks filled with fluid. Water hammer is one of the consequences that may occur accidentally in the reactors cooling system. The pressure level can exceed the limits given by the manufacturer, and it leads to the failure of the pipes integrity or nuclear fuel elements fixation in the core. Cooling system involves many components, and when a flow control component changes abruptly its status (for example, a valve closing or pump trip), it causes rapid changes in velocity and propagates pressure pulses in short time. The cooling system is equipped with flapper valve and flywheel which overcomes the transient issues. A pump or check valve may be stopped or closed abruptly and may cause bad impacts on the system which is simulated with soft trip using flywheel and without flywheel in case of its failure for any accidental reasons. In addition the abrupt valve closure is deemed as a major issue in the system if occurred. AFT Impulse 5.0 software is used to simulate and study the transient of each case. The simulation appears that the reactor cooling system may suffer from surge that may occur during the sudden closure of check valve but in other hand it can be avoided by regular maintenance of flapper valve to open in timely manner. [ABSTRACT FROM AUTHOR]

The paper gives an overview of foreign developments of flywheel energy storage systems for hybrid power plants, describes the design of the first in Russia 5 MJ flywheel energy storage system with magnetic suspension based on high-temperature superconductors. [ABSTRACT FROM AUTHOR]

Designing touch-down bearings (TDB) for outer rotor flywheels operated under high vacuum conditions constitutes a challenging task. Due to their large diameters, conventional TDB cannot suited well, and a planetary design is applied, consisting of a number of small rolling elements distributed around the stator. Since the amplitude of the peak loads during a drop-down lies close to the static load rating of the bearings, it is expected that their service life can be increased by reducing the maximum forces. Therefore, this paper investigates the influence of elastomer rings around the outer rings in the TDB using simulations. For this purpose, the structure and the models used for contact force calculation in the ANEAS simulation software are presented, especially the modelling of the elastomers. Based on the requirements for a TDB in a flywheel application, three different elastomers (FKM, VMQ, EPDM) are selected for the investigation. The results of the simulations show that stiffness and the type of material strongly influence the maximum force. The best results are obtained using FKM, leading to a reduction of the force amplitude in a wide stiffness range. [ABSTRACT FROM AUTHOR]

Beato, M, Madruga-Parera, M, Piqueras-Sanchiz, F, Moreno-Perez, V, and Romero-Rodriguez, D. Acute effect of eccentric overload exercises on change of direction performance and lower-limb muscle contractile function. J Strength Cond Res 35(12): 3327-3333, 2021-This study aimed to evaluate the postactivation potentiation (PAP) effects following eccentric overload (EOL) exercises on change of direction (COD) performance and muscle contractile function. Thirty-one male soccer players (age 21 +/- 4 years; body mass 77.0 +/- 5.2 kg) were involved in a cross-sectional study. Dominant-leg (COD-5mD) and non-dominant-leg (COD-5mND) shuttle tests were performed 4 minutes after the EOL exercises. Muscle contractile function was assessed by tensiomyography (TMG) such as muscle contraction time (Tc), time delay (Td) and displacement of the muscle belly (Dm) of vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF). Eccentric overload exercises were: (a) cross-cutting step with inertial conical pulley (INC = 11 subjects), (b) flywheel leg extension (EXT = 10 subjects), and flywheel yo-yo squat exercise (SQU = 10 subjects). Differences baseline-post were found on COD-5mD (p < 0.001) and on COD-5mND (p < 0.001), but not between groups (p > 0.05) following EOL exercises. Differences from baseline were found in VL Td (p < 0.001), VM Td (p = 0.003), RF Tc (p < 0.001), and RF Td (p < 0.001) with no significant differences between the EOL exercises. This study reported a significant positive PAP response on COD-5mD and COD-5mND after 4 minutes of recovery after EOL exercises (INC, EXT and SQU) in soccer players. For the first time, it has been reported that EOL exercises acutely affect TMG variables (e.g. Tc and Td) in lower limbs. Such results related to changes in muscular contractile functions may contribute to explain the physiological mechanisms (e.g. neuromuscular factors) associated with PAP effect. [ABSTRACT FROM AUTHOR]

Synchronous vibration and gyroscopic effect are the key factors affecting the global stability of flywheel batteries in the full speed region. The existing control methods generally treat them as two separate problems; however, they have something in common that can be exploited. In this article, a novel stability control method based on golden frequency section point is proposed for gyroscopic effect and synchronous vibration. The golden frequency section point is the bifurcation point of the nutation and precession of gyroscopic effect, and it is also the switching point of the control method with synchronous vibration at low and high speed. A case study of the centripetal force magnetic bearing-rotor (CFT-MB-R) system is taken as an example to verify it. First, the dynamic model of magnetic bearing rotor system is established. Then, the golden frequency section point is designed, and on this basis, the stability in the low-speed region and the high speed region are analyzed, respectively. Finally, simulations show that the vibration amplitude is reduced by nearly 50% at low speed and 66.6% at high speed. Moreover, the vehicle condition simulation results show the robustness of the system can also be improved. The experimental results further indicate that the method is an effective in suppressing the synchronous vibration and gyroscopic effect of the rotor system, and the stability and even robustness of the system can be greatly improved. [ABSTRACT FROM AUTHOR]

The popularity of the eBus has been increasing rapidly in recent years due to its low greenhouse gases (GHG) emissions and its low dependence on fossil fuels. This incremental use of the eBus increases the burden to the power grid for its charging. Charging eBus requires a high amount of power for a feasible amount of time. Therefore, developing a fast-charging station (FCS) integrated with Micro Energy Grid (MEG) and hybrid energy storage is crucial for charging eBuses. This paper presents a design of FCS for eBus that integrates MEG with hybrid energy storage with the energy management system. To reduce the dependency on the main utility grid, a hybrid micro energy grid based on a renewable source (i.e., PV) have been included. In addition, hybrid energy storage of batteries and flywheels has also been developed to mitigate the power demand of the fast-charging station during peak time. Furthermore, a multiple-input DC-DC converter has been developed for managing the DC power transfer between the common DC bus and the multiple energy sources. Finally, an energy management system and the controller has been designed to achieve an extensive performance from the fast charging station. MATLAB Simulink has been used for the simulation work of the overall design. Different test case scenarios are tested for evaluating the performance parameters of the proposed FCS and also for evaluating its performance. [ABSTRACT FROM AUTHOR]

The latching control represents an attractive alternative to increase the power absorption of wave energy converters (WECs) by tuning the phase of oscillator velocity to the wave excitation phase. However, increasing the amplitude of motion of the floating body is not the only challenge to obtain a good performance of the WEC. It also depends on the efficiency of the power take-off system (PTO). This study aims to address the actual power performance and operation of a heaving point absorber with a direct mechanical drive PTO system controlled by latching. The PTO characteristics, such as the gear ratio, the flywheel inertia, and the electric generator, are analyzed in the WEC performance. Three cylindrical point absorbers are also considered in the present study. A wave-to-wire model is developed to simulate the coupled hydro-electro-mechanical system in regular waves. The wave energy converter (WEC) performance is analyzed using the potential linear theory but considering the viscous damping effect according to the Morison equation to avoid the overestimated responses of the linear theory near resonance when the latching control system is applied. The latching control system increases the mean power. However, the increase is not significant if the parameters that characterize the WEC provide a considerable mean power. The performance of the proposed mechanical power take-off depends on the gear ratio and flywheel. However, the gear ratio shows a more significant influence than the flywheel inertia. The operating range of the generator and the diameter/draft ratio of the buoy also influence the PTO performance. [ABSTRACT FROM AUTHOR]

In this paper, the complementary characteristic of battery and flywheel in a PV/battery/flywheel hybrid energy storage system is explored for a solar PV-powered application. The impact of hybridising flywheel storage technologies with battery on the ageing of battery and its economic effectiveness when used with a PV system is presented. The ageing of a lead acid battery is modelled using Schiffer weighted Ah-throughput model while the economic analysis is modelled using total cost of ownership approach. Two scenarios (i.e. PV/Battery and PV/Battery/flywheel) are created to appreciate the complementary characteristics of a hybrid storage system in a PV-powered application. Sensitivity analysis was also carried out to understand the effect of a change in degradation and corrosion limit as well as charging and discharging current on the ageing of a lead acid battery. Some of the key results reveal that a hybrid of Battery/Flywheel presents a lower capital and total cost of ownership compared to battery only when used in a PV powered-combined fishery and poultry farm. The results also show that the life of a lead acid battery can be extended when combined with a flywheel compared to a battery only storage system.

ABSTRACT The kinetic energy was produced by a moving vehicle can be used to generate power by using a speed breaker. The kinetic energy is converted into mechanical energy by altering a reciprocating connecting rod into rotation of flywheel, then it is transmitted to the generator in order to produce electrical energy. The purpose of this study was to determine the electrical energy generated from the crankshaft type speed breaker. Speed breaker used has 3 ramps with a maximum ramp height of 10 cm. the load and speed of vehicles passing the ramp are varied 72 kg, 82.5 kg, 88.7 kg at speeds of 5 km/h, 10 km/h, 15 km/h. The result of the study shows that a vehicle with the mass of 88,7 kg was able to generate a 19 V of electric voltage, 32 A of electric current and 486,4 Watts. That power is stored in a 12 V and 3 Ah batteries that needed 0.094 hour for charging. Keywords: Flywheel, Generator, Kinetic energy, Speed breaker ABSTRAK Energi kinetik yang dihasilkan oleh kendaraan yang bergerak dapat digunakan untuk menghasilkan daya dengan menggunakan speed breaker. Energi kinetik diubah menjadi energi mekanik dengan mengubah batang penghubung bolak-balik menjadi rotasi roda gila, kemudian ditransmisikan ke generator untuk menghasilkan energi listrik. Tujuan dari penelitian ini adalah untuk mengetahui energi listrik yang dihasilkan dari speed breaker tipe poros engkol. speed breaker yang digunakan memiliki 3 ramp dengan tinggi maksimum ramp 10 cm. beban dan kecepatan kendaraan yang melewati ramp di variasikan masing - masing 72 kg, 82,5 kg, 88,7 kg dengan kecepatan 5 km/h, 10 km/h, 15km/h. Hasil penelitian menunjukkan bahwa kendaraan dengan massa 88,7 kg mampu menghasilkan tegangan listrik 19 V, arus listrik 32 A, dan 486,4 Watt. Daya itu disimpan dalam baterai 12 V dan 3 Ah yang membutuhkan 0,094 jam untuk diisi daya. Kata kunci: Energi kinetik, Generator, Roda gila, Speed breaker

In this paper, the complementary role of Finite Element Analysis (FEA) and Modal Analysis is studied using ANSYS Mechanical APDL. Primarily, two models (2D and 3D) of the flywheel are designed. Then, Finite Element (FE) static-stress analysis of the model was carried out, and it is found that the maximum von Mises stress (403 MPa) on the flywheel is lower than the yield stress (850 MPa) level, i.e. the design of the flywheel is safe. Afterwards, the Modal Analysis of the 3D model is carried out and six mode shapes are obtained at six different natural frequencies. Furthermore, Campbell diagram is plotted and two natural frequencies are identified. Moreover, mode shapes are plotted at the two critical speeds corresponding to their respective damped natural frequencies. The mode shapes are found to be stable, and therefore it can be remarked that the flywheel model is safe to operate within 12000 rpm. Finally, the performance of ANSYS models is determined by comparing analytical solution with the ANSYS results and the ANSYS solutions are accurate and robust.

The global climate protection policy aimed at achieving a zero greenhouse gas emissions target has led to the fast incorporation of large-scale photovoltaics into the power network. The conventional AC grid was not modeled to be incorporated with large-scale non-synchronous inverter-based energy resources (IBR). Incorporating inertia-free IBR into the grid leads to technical issues such as the degradation of system strength and inertia, therefore affecting the safety and reliability of the electrical power system. This research introduced a new solution to incorporate a flywheel in the rotor of a synchronous machine to improve the dynamic inertia control during a system disruption and to maintain the constancy of the system. The objective of this work is to enhance large-scale photovoltaic systems in such a way that they can avoid failures during a fault. A model of transient constancy with two synchronous generators and a LSPV is established in PowerWorld modeling software. A line-to-ground and three-phase fault are simulated in a system with up to 50% IBR penetration. The outcomes showed that the power network was able to ride through faults (RTFs) and that the stability of frequency and voltage are enhanced because of a flywheel that improved grid inertia and strength.

With the development of the global economy and the increase in environmental awareness, energy technology in transportation, especially the application of energy storage technology in rail transportation, has become a key area of research. Rail transportation systems are characterized by high energy consumption and poor power quality due to the more flexible regulation capability of energy storage technology in these aspects. This paper summarizes the latest research results on energy storage in rail transportation systems, matches the characteristics of energy storage technologies with the energy storage needs of rail transportation, and analyzes the operation of energy storage systems in different scenarios. The adaptability of batteries, supercapacitors, and flywheels as energy storage systems for rail transportation is summarized and compared. The topologies and integration methods of various energy storage systems are studied. The control strategies under each control of rail transportation are summarized and proposed. The future development direction of energy storage system for rail transportation prospects and the corresponding reference is provided for the engineering of energy storage technology in the field of rail transportation.

In this paper, a Frequency Stability Constrained Unit Commitment (FSCUC) model is presented. The on/off status of generating units, generation levels and operating reserves are optimized to minimize the operational daily costs. The frequency stability constraints are included in the proposed FSCUC model to guarantee the safety of System Frequency Response (SFR) under sudden generation outages. A new multi-area SFR model is proposed to capture the regional dynamics of system frequency with considering the impacts of transmission network. An SFR model is developed for each electric region and then the resulted regional SFRs are coupled via a set of constraints. In order to enhance the primary SFR and keep the daily operating point at its economic schedule, Flywheel Energy Storage (FES) devices are utilized in the proposed FSCUC model. The proposed multi-area SFR model allows the optimal allocation of operating reserve and the accurate modeling of FESs in FSCUC model. The proposed FSCUC model is formulated as a Mixed Integer Linear Programming (MILP) problem and is applied over the IEEE 118-bus test system to show the accuracy of the proposed multi-region SFR and the impact of FES in frequency support. The developed MILP model is solved using CPLEX in GAMS. [ABSTRACT FROM AUTHOR]

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Angular motion of a dual-spin satellite with a pitch flywheel with constant rotation rate is considered. While the satellite is equipped with magnetorquers, damping control ensures the stabilization in the orbital axes. Another type of control is proposed to rotate the satellite in the orbital plane in arbitrary direction. The resulting satellite motion is analyzed. Semi-analytic approach is developed to find the amplitudes of the periodic oscillations of the satellite in the vicinity of the required attitude. Planar motion on the polar orbit and small oscillations on the circumpolar orbit are covered. Results are verified with the numerical simulation. • Satellite with a rotor and magnetorquers is considered. • Magnetic control is developed to provide the rotation around the rotor axis. • Planar periodic motion on the polar orbit is analyzed. • Spatial motion on a circumpolar orbit is studied. • Numerical simulation is performed to verify the approximate results. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the postactivation potentiation (PAP) effects of an eccentric overload (EOL) exercise on vertical and horizontal jumps and change of direction (COD) performance. Twelve healthy physically active male subjects were involved in a crossover study. The subjects performed 3 sets of 6 repetitions of EOL half squats for maximal power using a flywheel ergometer. Postactivation potentiation using an EOL exercise was compared between amedium(MEOL) vs. high inertia (H-EOL) experimental condition. Long jump (LJ) was recorded at 30 seconds, 3, and 6 minutes after both EOL exercises and compared with baseline values (control). The same procedure was used to assess countermovement jump(CMJ) height and peak power and 5-mCODtest (COD-5m). A fullyBayesian statistical approach to provide probabilistic statementswas used in this study. Long jump performance reported improvements after M-EOL and H-EOL exercise (Bayes factor [BF10]532.7, strong; BF105 9.2, moderate), respectively. Counter movement jumpheight (BF105135.6, extreme; BF10.200, extreme), CMJ peak power (BF10. 200, extreme; BF10556.1, very strong), andCOD-5m(BF10555.7, very strong; BF10516.4, strong) reported improvements after MEOL and H-EOL exercise, respectively. Between analysis did not report meaningful differences in performance between M-EOL and H-EOL exercises. The present outcomes highlight that PAP using an EOL (M-EOL and H-EOL) improves LJ, CMJ height, CMJ peak power, and COD-5m in male athletes. The optimal time window for the PAP effect was found for both EOL conditions from 3 to 6 minutes. However, M-EOL and H-EOL produce similar PAP effect on LJ, CMJ, and COD-5m tasks. [ABSTRACT FROM AUTHOR]

This article proposes a topology of special axial split phase (ASP) bearingless switched reluctance (BSR) machine for flywheel applications named ASP-bearingless flywheel (ASP-BF) machine, which adopts hybrid-inner-stator permanent magnet (PM) structure and exhibits complete decoupling of torque and radial suspension force, four degrees-of-freedom (DOF) actively controlled suspension, high torque and radial force density. The topologies of conventional radial split phase (RSP)-BSR machines and the proposed ASP-BF machine are comparatively investigated. It is found that problems of conventional RSP-BSR machines, i.e., the radial suspension force generation dead zone and strong coupling of radial suspension force and torque, can be solved in ASP-BF machines and the suspension DOF can be doubled. Electromagnetic performances, including magnetic field distribution, inductance, torque, radial force are comprehensively investigated. Further, the concept of degree-of-coupling (DOC) is introduced, and the DOCs of the proposed machine and conventional machines are quantitatively analyzed and compared. It shows that the DOC of ASP-BF machine in two cases are 3.41% and 4.05%, less than a quarter of the conventional 8/10 pole machine (22% and 16%) and less than half of the 12/14 pole machine (8.57% and 11.3%). Finally, a 3 kW/100 Wh prototype is built and the experiments proved the validity. [ABSTRACT FROM AUTHOR]

Power and energy ratings are the most important parameters of Flywheel Energy Storage System (FESS) which have a crucial influence on its dynamic performance in frequency regulation applications. In order to achieve the optimum dynamic performance of FESS, an integrated model is required which includes key parameters of the power network and FESS. In this paper, an integrated transfer function of FESS connected to a single-bus aggregated power system is presented. The proposed model includes both power network and FESS parameters. Moreover, the model is linearized to facilitate the application of the parameter screening approach which recognizes the most influential parameters through Taguchi method. Afterwards, combined Response Surface Methodology (RSM)-GA optimization algorithm is utilized based on an accurate approximation of the system transfer function. In order to obtain FESS power and energy ratings on the basis of lowest capital price and best dynamic response objective functions, optimization algorithm is used. The simulation and experimental studies confirm the validity of the proposed modelling and optimization approach. [ABSTRACT FROM AUTHOR]

Designing touch-down bearings (TDB) for outer rotor flywheels operated under high vacuum conditions constitutes a challenging task. Due to their large diameters, conventional TDB cannot suited well, and a planetary design is applied, consisting of a number of small rolling elements distributed around the stator. Since the amplitude of the peak loads during a drop-down lies close to the static load rating of the bearings, it is expected that their service life can be increased by reducing the maximum forces. Therefore, this paper investigates the influence of elastomer rings around the outer rings in the TDB using simulations. For this purpose, the structure and the models used for contact force calculation in the ANEAS simulation software are presented, especially the modelling of the elastomers. Based on the requirements for a TDB in a flywheel application, three different elastomers (FKM, VMQ, EPDM) are selected for the investigation. The results of the simulations show that stiffness and the type of material strongly influence the maximum force. The best results are obtained using FKM, leading to a reduction of the force amplitude in a wide stiffness range.

Because of the operating environment and load, the main fault form of flywheel bearing is the friction fault between the cage and the rolling elements, which often lead to an increase in the friction torque of the bearing and even to the failure of the flywheel. However, due to the complex mechanism of the friction fault, the characteristic frequencies often used to indicate cage failure are not obvious, which makes it difficult to monitor and quantitatively judge such faults. Therefore, this paper studies the mechanism of the friction fault of the flywheel bearing cage and establishes its fault feature identification method. Firstly, the basic dynamic model of the bearing is established in this paper, and the friction between the cage and the rolling elements is simulated by the variable stiffness. The influence law of the bearing vibration response reveals the relationship between the periodic fluctuation of cage-rolling element friction failure and the bearing load. After analyzing the envelope spectrum of the vibration data, it was found that when a friction fault occurred between the cage and the rolling element, the rotation frequency component of the cage modulated the rotational frequency component of the rolling element, that is, the side frequency components appeared on both sides of the characteristic frequency of the rolling element (with the characteristic frequency of the cage as the interval). In addition, the modulation frequency components of the cage and rolling element changed with the severity of the fault. Then, a modulation sideband ratio method based on envelope spectrum was proposed to qualitatively diagnose the severity of the cage-rolling element friction faults. Finally, the effectiveness of the presented method was verified by experiments.

The recent and growing focus on reproducibility in neuroimaging studies has led many major academic centers to use cloud-based imaging databases for storing, analyzing, and sharing complex imaging data. Flywheel is one such database platform that offers easily accessible, large-scale data management, along with a framework for reproducible analyses through containerized pipelines. The Brain Imaging Data Structure (BIDS) is the de facto standard for neuroimaging data, but curating neuroimaging data into BIDS can be a challenging and time-consuming task. In particular, standard solutions for BIDS curation are limited on Flywheel. To address these challenges, we developed “FlywheelTools,” a software toolbox for reproducible data curation and manipulation on Flywheel. FlywheelTools includes two elements: fw-heudiconv, for heuristic-driven curation of data into BIDS, and flaudit, which audits and inventories projects on Flywheel. Together, these tools accelerate reproducible neuroscience research on the widely used Flywheel platform.