Search Results (20)

This study introduces a flywheel rotor support structure for an active magnetic suspension flywheel energy storage system. In this structure, there is an axial offset between the axial-bearing position and the mass-center of the flywheel rotor, which affects the tilting rotation of the flywheel rotor and which causes the coupling between its tilting rotation and radial motion. Therefore, the influence of the bearing position on the vibration characteristics of the flywheel rotor is explored in this paper. The tilting rotation constraint of the flywheel rotor by axial active magnetic bearing (AAMB) is analyzed, and the radial active magnetic bearing (RAMB) is equivalently treated with dynamic stiffness and dynamic damping. Based on this, a dynamic model of the active magnetic suspension rigid flywheel rotor, considering the position parameter of the axial bearing, is established. To quantify the axial offset between the position of the AAMB and the mass-center of the flywheel rotor, the axial-bearing position offset ratio γ is defined. The variation trend of the vibration characteristics of flywheel rotor with γ is discussed, and its correctness is validated through experiments. It is indicated that, with the increase of γ, the second-order positive precession frequency of the flywheel rotor decreases obviously, and the influence of the gyroscope torque gradually weakens. Meanwhile, its second-order critical speed ω_2c decreases significantly (when γ is 0.5, ω_2c decreases by about 62%); ω_2c corresponds to the inclined mode, revealing that the offset ratio γ has a prominent influence on the critical speed under this mode. In addition, as γ increases, the mass unbalance response amplitude of the flywheel rotor under the speed of ω_2c decreases significantly. The reasonable design of the axial-bearing position parameter can effectively improve the operational stability of the active magnetic suspension flywheel energy storage system. Full article

The research object of this paper is a new type of multi-functional, air-gap-type, vehicle-mounted magnetic suspension flywheel battery. It is a new energy storage technology with a long working life, high energy conversion efficiency, multiple charging and discharging times, low carbon and environmental protection. However, when the vehicle-mounted flywheel battery is operating, it will inevitably be disturbed by road conditions, resulting in loose sensors and feedback errors, thereby reducing the control accuracy and reliability of the system. To solve these problems, a sensorless control system came into being. It samples the current of the magnetic bearing coil through the hardware circuit and converts it into displacement for real-time control, eliminating the risk of sensor failure. However, the control accuracy of the traditional sensorless system is relatively low. Therefore, this paper adopts a BP (backpropagation) neural network PID controller based on genetic algorithm optimization on the basis of the sensorless control system. Through the joint simulation of the dynamic simulation software ADAMS/VIEW2018 and MATLAB2022b, the optimal PID control parameter database for complex road conditions is established. Through sensorless technology, the current of the flywheel battery is converted into the position error for extensive training so that the genetic BP neural network PID controller can accurately identify the current complex road conditions according to the position error, so as to provide the optimal PID control parameters corresponding to the road conditions to carry out accurate real-time stability control of the flywheel rotor. The experimental results show that the method can effectively reduce feedback errors, improve the control accuracy, and output optimal control parameters in real time under complex road conditions, which significantly improves the reliability and control performance of the vehicle flywheel battery system. Full article

A magnetic suspension bearing is a device that suspends the rotating shaft in a balanced position by magnetic force, thereby eliminating the friction between the rotor and the stator. Different from traditional bearing support methods, magnetic bearings show significant advantages in terms of speed, accuracy, and loss. Because there is no contact, magnetic bearings enable high-speed operation, precise control, and zero friction. Magnetic bearings, with their excellent performance, are widely applied in fields such as industrial production, flywheel energy storage, and aerospace. However, with the continuous growth of the demand for high-performance bearings and the deepening of the concept of low-carbon and environmental protection, breakthroughs in the key technologies of magnetic bearings are urgently needed. In this paper, relevant research on magnetic bearings is summarized. Magnetic bearings are classified according to the different ways in which they generate suspension forces. Research on the topological structure design, mathematical modeling, and control strategies of the magnetic bearing system is covered. The aim is to provide readers and researchers with a comprehensive overview of the key technologies of magnetic bearings from a new perspective. Full article

In this study, an accurate suspension force modeling method for the magnetic bearings of flywheel batteries considering degree-of-freedom (DOF) interactions and their control system is proposed to solve the problem that the traditional flywheel battery suspension force model does not consider DOF interactions, which makes the control system control effect poor. Firstly, according to the structural characteristics of the flywheel battery used, a suspension force model is established for the radial and axial magnetic bearings, which are most seriously interfered with by the torsional degrees of freedom of the flywheel battery. Next, by proposing DOF interaction factors, the complex changes due to DOF interactions are cleverly summarized into several interaction factors applied to the fundamental model to achieve accurate suspension force modeling considering DOF interactions. To better adapt the established accurate model and ensure precise control of the flywheel battery system under various working conditions, the firefly algorithm is employed to optimize the BP neural network (FA-BPNN). This optimization regulates the control system’s parameters, enabling the achievement of optimal control parameters in different scenarios and enhancing control efficiency. Compared to the flywheel battery controlled using the fundamental model, the radial and axial displacements are reduced by more than 30 percent and 20 percent, respectively, in the uphill condition using the accurate model with FA-BPNN. Full article

Compared to traditional, static-based flywheel systems, vehicle-mounted magnetic suspension flywheels face more complex operating conditions, and existing control strategies usually regard disturbances in vehicles under different operating conditions to be the same problem. Therefore, it is necessary to determine the interference from complex operating conditions and reasonably distinguish among them under different operating conditions to provide flywheel systems with strong stability (the rotor offset was less than 0.025 mm). Thus, this paper proposes a high-stability control strategy for flywheels based on the classification of vehicle-driving conditions and designs its control strategy by taking the vehicle-mounted magnetic suspension flywheel with a virtual inertia spindle as an example. First, according to the different vehicle working conditions and the varying interference intensities affecting the flywheel system, the working mode is divided into four modes. Considering the obvious differences in each working mode, it is proposed to use BP neural network optimization based on the simulated annealing algorithm (SA-BPNN) to determine the flywheel’s working condition. A relatively simple neural network can improve the response speed of the whole system. It also has a good effect. Secondly, it is proposed to use deep learning models based on convolutional neural networks, long short-term memory networks and attention mechanisms (CNN+LSTM+ATTENTION) to train the corresponding control parameters under each working condition to judge and predict the control parameters under different working conditions. Three evaluation parameters are used to evaluate the training results, and all achieved good results. Finally, the classification of working conditions and performance tests are carried out. The experimental results show the effectiveness and superiority of the proposed control strategy. Full article

With the continuous improvement of the performance and capabilities of spacecrafts, the application of active magnetic bearings (AMBs) has become a major focus in current research. The AMBs-flywheel system is not only responsible for attitude control but also provides the required energy during shadow periods. In magnetically suspended single gimbal control moment gyroscope (SGCMG), self-excited vibration caused by high-speed rotor rotation significantly affects the stability of the AMB system. The research focus lies in magnetically supporting the flywheel at high speeds with low power consumption to explore gyroscopic mechanics at ultra-high speeds and assess the corresponding stability. This study presents an assessment of the stability performance of a high-speed flywheel equipped on a single gimbal with an angular momentum of 75 Nm. To achieve ultra-high-speed operation under low driving power, a high-precise dynamic balance was performed followed by a novel unbalance control strategy of a radial and axial automatic balancing algorithm to suppress effectively synchronous vibrations due to nutation and precession. Corresponding experiments including static stable suspension experiments as well as low-speed, high-speed, and series-based stability assessments were conducted. Stable suspension at any speed ranging from 0 to 30,000 r/min was successfully implemented. The stability performance of the high-speed flywheel on a rotating platform at different gimbal speeds was verified, with a maximum speed reaching 31,200 r/min. The entire output torque process within the range of 30,000 r/min was revealed. Full article

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. Full article

The planetary flywheel can significantly reduce the weight of the flywheel, allowing the inerter to be lightweight. When a planetary flywheel ball screw inerter-based active actuator is used in a vehicle suspension system, the nonlinear features of the actuator affect vehicle performance. The planetary flywheel inerter actuator’s nonlinear dynamic model is constructed in this study based on the dynamic features of the planetary flywheel ball screw inerter and the electromagnetic torque generating mechanism of the permanent magnet synchronous motor. The impact of ball screw–nut friction, transmission clearance, planetary gear friction, and gear backlash on the performance of an active tuned inerter damper suspension is then investigated. As a result, the impact and sensitivity of numerous nonlinear parameters on suspension performance are shown, providing a theoretical foundation for the design of planetary flywheel inerter actuator and active inerter suspension. Full article

The existing model of magnetic suspension force for flywheel batteries mainly focuses on the internal magnetic field and foundation motions. However, when applied to vehicle-mounted occasions, the accuracy of the model will inevitably be affected by the vehicle vibration system and road conditions. Therefore, in view of the shortcomings of the existing research, a typical road condition (pulse road excitation) is taken as an example in this study to establish a model of magnetic suspension force that comprehensively considers automobile suspension and pulse road excitation. First, on the basis of a static model for magnetic suspension force using the equivalent magnetic circuit method, a magnetic suspension force dynamic model that takes into account the influence of automobile suspension and pulse road excitation is established. The rules of dynamic response under the influence of automobile suspension and pulse road excitation are summarized, and the foundation offset is corrected in the form of main migration points. Therefore, a correction model of magnetic suspension force is established. Finally, performance tests are carried out. The better anti-interference capability of the correction model is proven by the experimental results. Full article

Bearingless switched reluctance motor (BSRM) adopts a doubly salient structure without windings on the rotor. BSRMs have the advantages of high rate of fault tolerance and simple structure, high power, super high speed and strong adaptability. They have broad application prospects in aerospace, flywheel energy storage, new energy and biomedical fields. Firstly, the suspension operation mechanism of a conventional double winding BSRM is described in this paper. The coupling between torque and suspension force is analyzed with a finite element method. On this basis, from the perspective of magnetic circuit optimization of the torque system and suspension system, the magnetic circuit design, decoupling mechanism and performance characteristics of self-decoupled BSRMs with different topological structures are described centering on the self-decoupled topology form of the BSRM. Finally, the study and development of BSRMs in the future are prospected based on the research status. Full article

The vibration performance is critical to the suspension control and the torque precision of the magnetically suspended momentum flywheel (MSMW). The translational and torsional vibration of the MSMW are investigated in this article, and the damping regulation method is proposed to improve the anti-vibration performance of the MSMW. Firstly, the modellings of the MSMW, including the dynamic models and the displacement coordinate, are developed, and the comprehensive damping characteristics of the MSMW are investigated. Moreover, the transfer functions of the translational and the torsional vibrations are established using the dimensionless model, and the relationship between the dynamic response and the stiffness/damping coefficient is studied. Furthermore, the numerical simulations of the dynamic response of the translational and torsional vibration are conducted. Finally, the experiments are designed to verify the vibration characteristics of the MSMW, and the dynamic displacements are measured to analyze the anti-vibration performance of the proposed damping regulation method. The results indicate that the displacement deflection of the translational vibration is reduced by 68.8%, and the angle deflection of the torsional vibration is mitigated by 71.2% by regulating the damping coefficient. Full article

Different from common cylindrical magnetic bearings, the spherical radial AC HMB has obvious advantages in suppressing the gyroscopic effect, thus it is very suitable for application in flywheel battery systems. In this study, a precise mathematical model of suspension forces is deduced adopting wide-area and universal modeling theories in detail for the spherical radial AC HMB. Different from the traditional Maxwell tensor method based on a cylindrical two-dimensional coordinate system, the improved Maxwell tensor method based on a spherical coordinate system has a wider range and versatility. Then, the detailed explanation about the accuracy, wide-area and universality are given. Further, based on the model, the control system is designed, which includes the overall schematic, hardware and software designs. Finally, stiffness and performance tests are conducted. The good results of the stiffness tests indicate the error between the proposed model and the force-deflection stiffness test results is less than 2.8%. The good performance test results show that, based on the established model and control system, the rotor will soon return to equilibrium position under the disturbance of vehicle action. Full article

The composite material flywheel rotor of a flywheel energy storage system (FESS) has a low natural frequency. When the system suffers from noise interference, the magnetic bearing generates a force with the same frequency as the natural frequency and causes vibration to occur. Thus, it is necessary to suppress the natural vibration of the magnetic suspended (MS) FESS. The LMS adaptive notch filter is generally adopted for vibration suppression. The vibration suppression performance of the system is different when the insertion position of the notch filter is different. This paper analyzes the influence of the notch filter in different insertion positions of the control system. Through the transfer function from noise to magnetic bearing force, theoretical analysis of the influence of different positions of the notch filter is performed. Corresponding experiments are performed in a 500 kW MS FESS prototype. The theoretical analysis is verified experimentally. Full article

In this paper, a new superconducting flywheel energy storage system is proposed, whose concept is different from other systems. The superconducting flywheel energy storage system is composed of a radial-type superconducting magnetic bearing (SMB), an induction motor, and some positioning actuators. The SMB is composed of a superconducting stator and a flywheel rotor. The flywheel rotor is suspended by the superconducting stator, whose one end is fixed to a stable and heavy base. Free-run experiments in the case of the unfixed stator are performed. The natural rotation decay curve, displacement at the upper position of the rotor and displacement at a lower position of the rotor are measured. Moreover, free-run experiments in the case of the fixed stator are performed, and the same dynamic characteristics of the unfixed stator are measured. Especially, impulse responses for the rotor in the case of an unfixed stator are very different from those in the case of a fixed stator. The experimental results discuss some important characteristics of the superconducting flywheel energy storage system, whose rotor is suspended by the superconducting stator. Full article

At present, the stability study of the flywheel battery system under the influence of road conditions is only limited to the analysis of dynamic characteristics but also lacks effective controller considering road disturbances. In order to solve this defect and further improve the robust performance of vehicular flywheel battery systems under road disturbances, a robust controller considering interference of road surface roughness is proposed. Firstly, on the basis of a brief introduction to flywheel battery system structure, the influence degree of the flywheel by road condition is compared to find the key areas most affected by road disturbance factors. Then the nonlinear dynamic model of the axial suspension system is constructed, and the actual road surface roughness is regarded as the unmodeled dynamics of the external disturbance emphatically. Following, the established unknown system dynamics is approximated by radial basis function (RBF) neural network based on the minimum parameter learning method, the control input is generated by sliding-mode control law, and the weight adjustment of neural network is replaced by the designed adaptive law of parameter estimation. The effects of different levels of road surface roughness on the system are simulated, and the robustness of the proposed controller is verified based on the Lyapunov method. Finally, the experimental platform to simulate road disturbances is designed ingeniously. Experimental results show that the proposed controller can make the flywheel battery system have good robustness under different road conditions. Full article