A Nonlinear Control Algorithm for Flywheel Energy Storage Systems in Discharging Mode

针对Buck-Boost变换器的非线性特征给飞轮储能系统的放电运行状态带来的控制问题,提出了电压电流双环非线性控制算法。基于输入/输出线性化理论,推导出电流内环的控制律,并证明了内动态的稳定性。电压外环采用鲁棒性强的滑模变结构控制方法,并增加限流环节,保证放电电路安全、稳定运行。在Matlab/Simulink仿真平台中搭建飞轮放电模型,对所提出非线性控制算法进行了仿真验证。仿真结果表明,相比于双环PI控制,该算法能够明显改善输出电压调节时间、超调量等动态特性,在输入电压存在大范围变化的情况下,输出电压能够保持恒定和较低的纹波系数。

Spacecraft Attitude Tracking and Energy Storage Using Flywheels

The control law of the flywheel in an integrated power and attitude control system （IPACS） for a spacecraft is investigated. The flywheels are used as attitude control actuators as well as energy storage device. A feedback control law for attitude tracking is firstly developed by using Lyapunov approach, and then a torque based control law of the flywheel is studied. The control torque vector of the flywheel is decomposed into three parts which are orthogonal to one another by using the method of singularity value decomposition （SVD）. One part is used to provide the attitude control torque, another part is used to store energy with given power, and the last part is used to accomplish wheel speed equalization to avoid wheel saturation caused by large difference among the wheel spin rates. A management scheme for energy storage power using kinetic energy feedback is proposed to keep energy balance, which can avoid wheel saturation caused by superfluous energy. Numerical simulation results demonstrate the effectiveness of the control scheme.

Analysis of the Comprehensive Physical Field for a New Flywheel Energy Storage Motor/Generator on Ships

A novel flywheel energy storage （FES） motor/generator （M/G） was proposed for marine systems. The purpose was to improve the power quality of a marine power system （MPS） and strengthen the energy recycle. Two structures including the magnetic or non-magnetic inner-rotor were contrasted in the magnetostatic field by using finite element analysis （FEA）. By optimally designing the size parameters, the average speed of FEA results of was 17 200 r/m, and the current was controlled between 62 and 68 A in the transient field. The electrical machine electromagnetism design was further optimized by the FEA in the temperature field, to find the local overheating point under the normal operation condition and provide guidance for the cooling system. Finally, it can be concluded from the comprehensive physical field analysis that the novel redundant structure M/G can improve the efficiency of the M/G and maintain the stability of the MPS.

Flywheel Energy Storage with Mechanical Input-Output for Regenerative Braking

The system presented in this paper allows the direct transfer of kinetic energy of a vehicle’s motion to a flywheel and vice-versa. For braking, a cable winds onto a pulley geared to the vehicle’s propulsion driveshaft as it unwinds from another pulley geared to the flywheel and then operates in reverse for the transfer of energy in the opposite direction. The cable windings are in one plane resulting in an effective pulley radius that increases when the cable is winding onto it and decreases when unwinding from it. Thus, an increasing driven-to-driving pulley velocity ratio is obtained during a period of energy transfer in either direction. A dynamic analysis simulating the process was developed. Its application is illustrated with a numerical solution based on specific assumed values of system parameters.

Dynamical investigation and parameter stability region analysis of a flywheel energy storage system in charging mode

In this paper, the dynamic behavior analysis of the electromechanical coupling characteristics of a flywheel energy storage system （FESS） with a permanent magnet （PM） brushless direct-current （DC） motor （BLDCM） is studied. The Hopf bifurcation theory and nonlinear methods are used to investigate the generation process and mechanism of the coupled dynamic behavior for the average current controlled FESS in the charging mode. First, the universal nonlinear dynamic model of the FESS based on the BLDCM is derived. Then, for a 0.01 kWh/1.6 kW FESS platform in the Key Laboratory of the Smart Grid at Tianjin University, the phase trajectory of the FESS from a stable state towards chaos is presented using numerical and stroboscopic methods, and all dynamic behaviors of the system in this process are captured. The characteristics of the low-frequency oscillation and the mechanism of the Hopf bifurcation are investigated based on the Routh stability criterion and nonlinear dynamic theory. It is shown that the Hopf bifurcation is directly due to the loss of control over the inductor current, which is caused by the system control parameters exceeding certain ranges. This coupling nonlinear process of the FESS affects the stability of the motor running and the efficiency of energy transfer. In this paper, we investigate into the effects of control parameter change on the stability and the stability regions of these parameters based on the averaged-model approach. Furthermore, the effect of the quantization error in the digital control system is considered to modify the stability regions of the control parameters. Finally, these theoretical results are verified through platform experiments.

Analysis of a Novel Mechanically Adjusted Variable Flux Permanent Magnet Homopolar Inductor Machine with Rotating Magnetic Poles for Flywheel Energy Storage System

Permanent magnet homopolar inductor machine(PMHIM) has attracted much attention in the field of flywheel energy storage system(FESS) due to its merits of simple structure,brushless excitation, and rotor flywheel integration. However, the air-gap flux generated by the PM cannot be adjusted, which would cause large electromagnetic losses in the standby operation state of FESS. To solve this problem, a novel mechanically adjusted variable flux permanent magnet homopolar inductor machine with rotating magnetic poles(RMP-PMHIM) is proposed in this paper. The permanent magnet poles are rotated by an auxiliary rotating device and the purpose of changing the air-gap flux is achieved. First, the structure and operation principle of the proposed RMP-PMHIM are explained. Second,the flux weakening principle of the RMP-PMHIM is analyzed and the equivalent magnetic circuit models under different flux weakening states are built. Third, the parameters of the PM and its fixed structure are optimized to obtain the good electromagnetic performance. Fourth, the electromagnetic performance, including the air-gap flux density, back-EMF, flux weakening ability, loss, etc. of the proposed RMP-PMHIM are investigated and compared. Compared with the non-rotating state of the PM of RPM-PMHIM, the air-gap flux density amplitude can be weakened by 99.95% when the PM rotation angle is 90 degrees, and the no-load core loss can be suppressed by 99.98%,which shows that the proposed RPM-PMHIM is a good candidate for the application of FESS.

Flywheel Energy Storage System Based on Boost DC-AC Converter

To extend the operating speed range of a conventional configuration of FESS （flywheel energy storage system）, an additional DC-DC boost converter is required between the machine and grid side converters to regulate the output voltage. This paper presents a new FESS based on three-phase boost inverter topology. The proposed system facilitates voltage boost capability directly in a single-stage. The main advantage of the three-phase boost inverter is the deployment of only six switches and undersized passive elements to obtain a boosted AC output voltage weighed against the input DC supply. In this paper, FESS based on boost inverter topology is modeled and simulated using MATLAB/S1MULINK. An experimental setup has been built for the three-phase boost inverter to present its boosting capability. The simulation and experimental results sustain the proposed configuration.

Improving Kinetic Energy Storage for Vehicles through the Combination of Rolling Element and Active Magnetic Bearing

The demand for short term energy storage providing high power for electric and hybrid-electric vehicles is increasing drastically. Stationary FESS （flywheel energy storage systems） is established as UPS （uninterruptible power supply） and represent an emerging market. In contrast, mobile FESSs are currently only used in a few application, e.g., in motor sports. To enable a wider use in personal and public transportation the life-span of the flywheel＇s bearings needs to be increased significantly. This paper presents an alternative approach to extend the lifespan of the flywheel＇s bearings significantly by using a CREAMB （combination of rolling element and active magnetic bearings）.

飞轮储能系统的计算机处理技术研究

目前能源消费与能源发展下的环保问题是我国能源研究的核心,飞轮储能功率较高且操作技术相对直接不会造成环境污染,是一种较为先进的储能技术。本文综述了飞轮储能系统的核心结构,包括飞轮转子结构以及飞轮轴承结构;同时历数了当前较为先进的针对飞轮储能电机控制的计算机处理控制技术,以期为后续研究提供一定思路。

新型储能技术进展与挑战Ⅱ:物理储能与储热技术

新型储能技术日益成为中国建设新型能源体系和新型电力系统的关键技术,已成为中国经济发展的新动能,将在促进可再生能源消纳、实现能源体系转型、提高能源利用效率、减少环境污染等方面发挥重要作用,相关技术研究也在快速发展。开展了该领域的系列评价性综述工作,分为电化学储能技术、物理储能与储热技术、储能集成与规划3个部分,对各类新型储能技术的应用领域、最新研究进展及局限性等问题进行了全面系统的对比分析,并进一步探讨了储能集成、安全、规划调度等储能系统相关领域面临的挑战及发展趋势。第2部分为物理储能与储热技术,重点对物理储能与储热技术中的压缩空气储能、飞轮储能、重力储能、相变储热、热化学储热和卡诺电池技术与工程的相关成果进行了综合分析与讨论。总体而言,物理储能和储热技术大多具有使用寿命长、安全性高的特点,且在能量转化过程中自身多具有转动惯量,属于电网支撑型的储能技术,可满足从大规模长时储能到高功率快速响应的不同需求。在新兴的物理储能和储热技术中,重力储能和卡诺电池的相关技术显示出良好的发展前景。

飞轮储能辅助火电机组一次调频及其性能评价

为促进太阳能、风能等新能源消纳,进一步拓宽火电储能技术升级和灵活性改造渠道,助力双碳目标和新型电力系统建设,提出增设储能系统辅助火电机组调频以解决火电机组爬坡慢、机组振荡不稳定等问题。基于国内外研究现状,提出机组以及储能系统荷电状态出力控制策略模型,通过Matlab/Simulink搭建两区域电网进行模拟仿真。结果表明,在阶跃扰动下区域1机组耦合1 MW飞轮储能系统后,峰值降至1.93×10^(-3)pu,降低4×10^(-4) pu,占原频率波动率的9.39%,机组实际出力从2.45×10^(-2)pu降至1.61×10^(-2)pu,降低34%。结果表明,在外界相同扰动条件下,采用飞轮储能辅助火电机组调频可有效减小系统频率波动量,减少汽轮机输出功率波动,提升调频性能。

基于NSGA-Ⅱ的飞轮-火电联合二次调频最优负荷分配策略

为了在提升飞轮-火电联合二次调频性能的同时控制调频成本、减少飞轮损耗,面向飞轮-火电联合系统,提出一种考虑自动发电控制(AGC)指令及电网频率偏差的基于多目标遗传算法的负荷分配策略。该策略以电网调频偏差、飞轮-火电出力能量和、飞轮损耗为三层最小化目标,考虑火电机组爬坡率及其负荷备用、飞轮荷电状态及其功率等约束条件,基于改进的非支配排序遗传算法(NSGA-Ⅱ),通过AGC功率指令变化速度及频率偏差动态调整飞轮与火电出力权重系数,以频率偏差及其变化方向调整飞轮虚拟下垂、惯性系数,求解飞轮-火电出力比例、飞轮下垂系数和飞轮惯性系数。结合中国宁夏某电厂飞轮储能系统辅助火电机组调频现场AGC指令等历史数据,在双区域两机系统模型上进行仿真实验,结果表明该负荷分配策略有效地减小了火电二次调频偏差和调节时间,提升了调频性能,同时也有效地控制了系统出力能量及飞轮损耗。

基于逐次变分模态分解的飞轮-火电一次调频控制策略

随着新型电力系统的大力建设与推广,火电机组面临的调频压力增大,提出一种逐次变分模态分解的飞轮-火电一次调频控制策略。首先,以飞轮储能和火电机组为研究对象,建立考虑新能源占比的飞轮-火电一次调频模型;其次,将一次调频功率指令利用逐次变分模态方法分解,由火电机组响应分解后的低频功率指令,同时设计飞轮储能下垂优化控制方法,实现飞轮储能与火电机组响应频率变化的协同控制;最后在不同工况下仿真验证,结果表明所提策略可有效避免火电机组一次调频时的频繁出力,减小火电机组响应频率变化时的调控要求,同时可最大限度地利用飞轮储能调频容量并保证飞轮储能调频期间的运行安全,进一步提升了系统的频率响应能力。

飞轮储能技术在断路器动态特性检测中的应用

在地铁列车断路器动态特性检测中,引入飞轮储能系统能够有效回收列车再生制动能量,稳定断路器开关动作电压,但单飞轮储能系统容量较小,难以满足列车再生制动能量利用需求,飞轮储能阵列(FESA)是解决这一问题的有效手段.首先,分析飞轮储能系统的数学模型和运行特性;然后,考虑稳压节能及弱磁需求,给出基于多电压阈值的单飞轮储能系统控制策略,并在此基础上针对飞轮阵列均速控制和工作模式管理等核心问题,提出基于转差修正控制和基于“电压-转速-电流”三闭环控制的两种飞轮储能阵列控制策略;最后,通过仿真和实验验证飞轮储能阵列控制策略的可行性.

飞轮储能蓄能器挖掘机动臂设计及负载特性分析

对飞轮储能蓄能器进行分析,在动臂驱动系统中加入了蓄能器以及轴向柱塞马达,以实现储存更多挖掘机动臂能量和节能控制的效果。研究利用速度传感器把测试得到的负载速度信号传输到比较器中,根据检测数据完成柱塞马达排量的实施调节功能,最终达到稳定的运行速度。研究结果表明:挖掘机阀控系统中选择一个循环下的液压执行元件进行能量利用率分析,执行元件的能量利用率达到了主泵输出的近81%,动臂能量回收占比为17.5%,回转机构的能量回收比例达到主泵输出能量8.9%。负载从位移为0的初始状态发生线性增大,表现出了稳定的运动性能,最终达到2.8 m的位移。环形活塞的压力与位移之间呈现线性变化的特征。位移由0提高到172 mm,压力则由2.1 MPa提高到3.2 MPa,实现了稳定的控制性能。

基于项目式金工实习钳工装配实践课程建设

以飞轮储能装置的钳工装配为研究对象,探讨了基于项目式金工实习的教学方法。通过项目式《金工实习》,学生可以全面参与飞轮储能装置的钳工装配过程,从设计、加工到调试,深入了解飞轮储能装置的结构和工作原理。通过实践操作,学生可以掌握钳工装配的基本技能和操作要领,培养了学生动手能力和实际操作能力。通过项目式金工实习,学生不仅提高了自身的技能水平,还对飞轮储能装置的钳工装配有了更深入的了解。这种实践性的学习方式有助于培养学生的实际操作能力和创新思维能力,提高学生的综合素质和就业竞争力。

基于模糊卡尔曼滤波和改进滑模控制的风电场飞轮储能控制策略

在风电场并网点处配置一定容量的飞轮储能装置(FESS)可以有效平滑并网功率,提高风电场的电网友好性。为提高FESS的功率响应速度,增强对风电功率波动的平抑效果,同时避免在功率波动太大时储能过充/过放,文章提出了一种基于模糊卡尔曼滤波和改进滑模控制(SMC)的飞轮储能控制策略。根据FESS的实时转速和功率自适应调节卡尔曼增益,将滤波结果与风电场实际输出功率的差值作为滑模控制器的输入,实现对飞轮储能的功率控制。仿真结果表明,文章提出的控制策略具有较好的动态响应特性,可以有效平滑风电功率,使其满足并网要求,在平滑过程中保证飞轮转速在限定范围内,有利于延长FESS的使用寿命。

飞轮储能阵列系统协调控制方法综述

因受材料、成本和技术等因素制约,提高单个飞轮储能装置的容量较为困难,难以满足长时间大功率的需求。对此提出使用飞轮阵列来提高飞轮系统的总储能容量,进而降低装置的研发和生产成本。对于飞轮阵列储能系统,研究各储能单元协调控制、相互配合的控制策略是实现阵列高效、安全运行的解决方案。从飞轮储能阵列系统拓扑结构、协调控制策略及协调控制算法进行全面的综述。从飞轮储能阵列不同并网拓扑结构出发,探讨了适用于直流母线并联和交流母线并联对应的功率分配控制策略;随后以飞轮储能阵列并行接入电网为切入点,分别对集中式、主从式与分布式协调控制算法进行比较研究和归纳总结,重点评述了分布式一致性算法优势,并在此基础上进一步总结基于智能算法高效率求解的功率分配控制策略。最后,指出了飞轮储能阵列系统并网运行协调控制面临的挑战。

计及风电场的飞轮储能一次调频控制策略

随着新能源渗透率的提高,电力系统频率稳定性问题愈加严重。本文提出一种改进飞轮储能辅助风电场一次调频的控制策略,分析风储系统的频率特性和容量配置,风电场采用虚拟惯性控制参与一次调频。由于风电场的输出功率根据自然风速随机变化,可能会导致飞轮长期运行至较高或较低转速的状态,在风速骤变时甚至会引起飞轮转速越限。采用虚拟下垂控制结合模糊规则防止飞轮转速越限,从而弥补风电场在一次调频中的功率缺额。通过仿真分析及实验验证阶跃扰动和连续扰动的工况下的频率特性,得出改进控制策略在阶跃扰动和连续负荷扰动2种工况下最大频率偏差更小、响应速度更快的结论.

存在初始静偏心的储能飞轮转子动力学特性

以大功率储能飞轮转子系统为研究对象,探究电机转子存在初始静偏心时飞轮动力学特性的变化规律。首先使用能量法求出电机转子不平衡磁拉力(UMP)与转子偏心位移之间的关系,采用Timoshenko梁单元模型建立包含UMP的飞轮转子机电耦合动力学模型,计算分析电机转子初始偏心量和偏心方向对飞轮稳态和瞬态特性的影响,得出以下结论:随着偏心量的增大,上轴承处轴心轨迹出现嵌套圆环,频谱出现3种频率成分且幅值增大,升速响应曲线共振峰的峰值增大,对应转速减小;当偏心方向改变且旋转一周时,转频等成分的幅值、升速响应曲线共振峰值产生明显的周期规律变化。