Optimization of cylindrical composite flywheel rotors for energy storage

The use of flywheel rotors for energy storage presents several advantages, including fast response time, high efficiency and long cycle lifetime. Also, the fact that the technology poses few environmental risks makes it an attractive solution for energy storage. However, widespread application of tailorable circumferentially wound composite flywheel rotors is hampered by the relatively low energy density that these rotors have been able to achieve. This contributes to high capital cost, which currently makes the flywheels prohibitively expensive for many applications. With the materials that are currently available, there seems to be ample room for improvement in the energy density achieved by composite flywheel rotors. To this aim, some of the design methods that have previously been proposed are herein studied, and our findings suggest that the manner in which the optimization problem is formulated is crucial to the design of high energy density flywheels. A new problem formulation is proposed, which is shown to lead to notable improvements in certain cases. By making use of the proposed problem formulation, flywheel rotors can be designed to consistently achieve high energy density relative to the materials that are made available. This can contribute towards lowering the cost of flywheel systems, and making flywheel energy storage viable for a wider range of applications.     

Topology optimization of energy storage flywheel

Structural and Multidisciplinary Optimization - To increase the energy storage density, one of the critical evaluations of flywheel performance, topology optimization is used to obtain the...     

Shape optimization of energy storage flywheel rotor

A flywheel plays an important role in storing energy in modern machine systems. Flywheels can store rotational energy at a high rotating speed and have the ability to deliver a high output power if the system needs a stored energy to overcome a sudden loading or keep rotating for an expected long time. The energy density (stored energy per unit mass) and the amount of rotational energy are the two essential parameters to evaluate the performance of energy storage flywheels. In order to improve the energy storage capability of flywheels, parametric geometry modeling and shape optimization method for optimizing the flywheel rotor geometry is proposed in the present paper. We first build the shape optimization model of flywheel by parametric geometry modeling method with the objective to maximize the energy density of a flywheel rotor. Then the downhill simplex method is adopted to solve the nonlinear optimization problem in multidimensional space. Finally, we obtain the optimized shapes of flywheel rotor which could significantly improve the energy storage capability and working safety performance compared with the traditional design flywheel of constant thickness rotor. It is found that the maximum structural stress constraint applied in the designed region has a remarkable effect on the shape optimization.

     

Cost optimization of a hybrid composite flywheel rotor with a split-type hub using combined analytical/numerical models

A procedure to find the optimal design of a flywheel with a split-type hub is presented. Since cost plays a decisive role in stationary flywheel energy storage applications, a trade-off between energy and cost is required. Applying a scaling technique, the multi-objective design problem is reduced to the maximization of the energy-per-cost ratio as the single objective. Both an analytical and a finite element model were studied. The latter was found to be more than three orders of magnitude more computationally expensive than the analytical model, while the analytical model can only be regarded as a coarse approximation. Multifidelity approaches were examined to reduce the computational expense while retaining the high accuracy and large modeling depth of the finite element model. Using a surrogate-based optimization strategy, the computational cost was reduced to only one third in comparison to using only the finite element model. A nonlinear interior-point method was employed to find the optimal rim thicknesses and rotational speed. The benefits of the split-type hub architecture were demonstrated.     

磁悬浮储能飞轮线性变参数鲁棒增益调度控制

针对强陀螺效应的磁悬浮储能飞轮转速快变引起的模型变化而带来的控制问题,设计了线性变参数增益调度鲁棒控制器.根据飞轮的线性变参数模型,设计的鲁棒增益调度控制器,能够保证其全转速范围内的鲁棒稳定性和性能.为降低控制器设计的保守性,在设计控制器时,可缩小转速区间,使控制性能得到提高.与按照非时变模型设计的鲁棒控制器相比,线性变参数鲁棒增益调度控制器可以实现以转速为参数的自适应调节,在全转速范围内,其鲁棒稳定性和性能均具有显著优势.仿真结果验证了此控制器的有效性和先进性.     

Research on simulation of ship electric propulsion system with flywheel energy storage system

Flywheel energy storage has been widely used to improve the ground electric power quality. This paper designed a flywheel energy storage device to improve ship electric propulsion system power grid quality. The practical mathematical models of flywheel energy storage and ship electric propulsion system were established. Simulation research on the effect of ship electric propulsion system power quality, made by flywheel energy storage, was completed by using the software Matlab/simulink. We have done a lot of simulation experiments on sudden load of ship integrated electric propulsion system, one system is with flywheel energy storage, another one is not with. Comparing with these simulation results, we can see that the flywheel energy storage designed in this paper has improved ship electric propulsion system network power quality as well as increases the reliability of the ship power grid. The conclusions can provide a theoretical guidance for the design of flywheel energy storage applied in ship integrated electric propulsion system.     

A hybrid multilevel approach for aeroelastic optimization of composite wing-box

The quest for finding optimum solutions to engineering problems has been existing for a long time. In the last decade several optimization techniques have been applied to the structural design of composite wing structures. Generally many of these proposed procedures have dealt with different disciplines such as aerodynamics, structures, or dynamics separately. However an aeronautical design process is multidisciplinary since it involves strong couplings and interactions among, for instance, aerodynamics, dynamics, flight mechanics and structures. The main problem in a multidisciplinary aircraft design is usually the development of an efficient method to integrate structures or structural properties, which can be considered both as “global” and “local” design variables. This paper describes an integrated aerodynamic / dynamic / structural optimization procedure for a composite wing-box design. The procedure combines an aeroelastic optimization of a composite wing based on a general purpose optimizer such as the Sequential Quadratic Programming (SQP) and a composite optimization using Genetic Algorithm (GA). Both the optimizations are implemented through a hybrid multilevel decomposition technique.     

Cost optimization of composite beams using genetic algorithms

This paper presents a genetic algorithm model for the cost optimization of composite beams based on the load and resistance factor design (LRFD) specifications of the AISC. The model formulation includes the cost of concrete, steel beam, and shear studs. Two design examples taken from the literature were analyzed in order to validate the proposed model, to illustrate its use, and to demonstrate its capabilities in optimizing composite beam designs. The results obtained show that the model is capable of achieving substantial cost savings. Hence, it can be of practical value to structural designers. A parametric study was also conducted to investigate the effects of beam spans and loadings on the cost optimization of composite beams.     

飞轮储能用电机可测性设计的应用研究

本文从模块化、层次化的思路出发,分析研究了飞轮储能用电机的可测性设计框架、分层标准和总体参数分析。提出了基于系统功能划分的电机可测性设计方案和对测试数据进行有效处理的方法,能够有效减少系统冗余测试和提高电机安全可靠性。     

A density-based topology optimization methodology for thermal energy storage systems

Structural and Multidisciplinary Optimization - As many renewable energy resources are prone to an intermittent production of energy and the electric energy demand varies on daily and seasonal...     

Characteristic model based all-coefficient adaptive control of an AMB suspended energy storage flywheel test rig

Feedback control of active magnetic bearing (AMB) suspended energy storage flywheel systems is critical in the operation of the systems and has been well studied. Both the classical proportional-integral-derivative (PID) control design method and modern control theory, such as H_∞ control and μ-synthesis, have been explored. PID control is easy to implement but is not effective in handling complex rotordynamics. Modern control design methods usually require a plant model and an accurate characterization of the uncertainties. In each case, few experimental validation results on the closed-loop performance are available because of the costs and the technical challenges associated with the construction of experimental test rigs. In this paper, we apply the characteristic model based all-coefficient adaptive control (ACAC) design method for the stabilization of an AMB suspended flywheel test rig we recently constructed. Both simulation and experimental results demonstrate strong closed-loop performance in spite of the simplicity of the control design and implementation.     

A quantile-based simulation optimization model for sizing hybrid renewable energy systems

As the public has gradually realized the adverse impacts brought by global warming, hybrid renewable energy system (HRES) has become increasingly popular because it can reduce dependence on fossil fuels, while maintaining the stability of power supply. While the HRES is an attractive option in many aspects, the fundamentally uncertain nature of renewable energy sources makes the determination of the proper sizing of the HRES a very challenging task. Contrasting with the existing models that are largely focused on expectation-based system performance, this paper provides a quantile-based simulation optimization model, followed by the development of an efficient solution methodology, to enable the control of the upside risk and, as a result, to enhance the decision quality regarding the sizing of HRES. One advantage of the proposed model is that they can be based on any existing deterministic model that carries a cost structure regarding the sizing of the HRES. Moreover, the proposed solution methodology, consisting of a Monte Carlo simulation method, quantile estimation techniques, and an efficient stochastic optimizer, allows for not only accurate estimation of the objective function value, but also quick identification of the optimal solution due to a uniquely-defined neighborhood structure. An extensive numerical experiment is conducted to verify the efficacy and efficiency of the proposed solution methodology. Finally, in collaboration with a partner in industry, the proposed model and the solution methodology are integrated into a decision support system to provide visualized results for sizing HRES in practice.     

储能汇聚参与辅助调频服务的协同优化算法

用户侧分布式储能是电网潜在的优质调频资源,它们的闲余时间和闲余电量未能得到很好的利用.本文以分布式储能集群为研究对象,基于状态势博奔理论提出了一种完全分布式的协同优化算法,实现分布式储能有效汇聚参与电网一次调频.为适应分布式储能频繁退出/参与调频辅助服务,本文首先将分布式储能一次调频问题转化为状态势博奔,依据分布式储能...     

磁悬浮飞轮储能系统机电耦合非线性动力学研究

针对磁悬浮飞轮储能系统的"磁悬浮飞轮-发电机"机电耦合非线性动力学特性进行研究.通过推导磁悬浮飞轮储能系统在偏心条件下的动能、势能、发电机系统的磁场能以及系统的耗散函数,由Lagrange-Maxwell方程建立磁悬浮飞轮系统和两相四极永磁发电机系统的机电耦合动力学方程.采用数值法对0.6MW磁悬浮飞轮储能系统进行了仿真分析,研究结果表明,系统机电耦合非线性方程存在稳定的与转速同频的基频和三倍频周期运动解,且基频振动幅值比三倍频振动幅值大.对于稳定的磁悬浮储能飞轮机电耦合系统,飞轮转速增大,或磁轴承系统刚度减小或阻尼增大,或磁场能(电枢反应磁场能或永磁励磁磁场能)减小,可使系统的非线性振动幅值减小.而增大磁轴承系统的刚度,或减小磁轴承系统的阻尼,或增大系统的磁场能有可能破坏机电耦合系统的稳定性,使飞轮失稳.     

矿用电动车混合储能系统Z源逆变器电流控制

针对应用于矿用电动车混合储能系统的传统Z源逆变器或单开关电感Z源逆变器存在电压增益、功率密度和转换效率均不高的问题,提出了一种新型Z源逆变器。该逆变器采用基于阵列式磁集成技术的模块化开关耦合电感单元替代传统Z源逆变器的电感,提高功率密度和电压增益,并通过引入辅助软开关支路实现功率器件零电压开关,提高转换效率。对基于新型Z源逆变器的混合储能系统进行了建模,通过分析极点,发现引起系统振荡的1对共轭极点及系统振荡处频率,结合模型进行了电流控制器参数设计,推导出电流控制器比例和积分参数的设计准则。仿真与实验结果验证了该电流控制器设计准则的正确性。     

电动汽车混合储能系统拓扑结构与控制策略综述

混合储能系统兼具高功率密度和高能量密度,可有效提升电动汽车动力性能和续驶里程.围绕电动汽车混合储能系统拓扑结构和控制策略,本文首先对混合储能系统及其典型储能装置进行概述,并对混合储能系统技术难点进行分析.之后在分析隔离型双向DC/DC变换器和非隔离型双向DC/DC变换器拓扑结构、工作原理和基本特性的基础上,综述分析了被动、半主动和全主动3种混合储能系统的工作原理和优缺点.然后,重点分析了基于规则的控制策略、基于优化的控制策略和混合控制策略3大类混合储能系统控制策略的工作原理.最后对混合储能系统的发展趋势进行了展望.     

Size optimization for hybrid photovoltaic–wind energy system using ant colony optimization for continuous domains based integer programming

In this paper, ant colony optimization for continuous domains (ACO_R) based integer programming is employed for size optimization in a hybrid photovoltaic (PV)–wind energy system. ACO_R is a direct extension of ant colony optimization (ACO). Also, it is the significant ant-based algorithm for continuous optimization. In this setting, the variables are first considered as real then rounded in each step of iteration. The number of solar panels, wind turbines and batteries are selected as decision variables of integer programming problem. The objective function of the PV–wind system design is the total design cost which is the sum of total capital cost and total maintenance cost that should be minimized. The optimization is separately performed for three renewable energy systems including hybrid systems, solar stand alone and wind stand alone. A complete data set, a regular optimization formulation and ACO_R based integer programming are the main features of this paper. The optimization results showed that this method gives the best results just in few seconds. Also, the results are compared with other artificial intelligent (AI) approaches and a conventional optimization method. Moreover, the results are very promising and prove that the authors’ proposed approach outperforms them in terms of reaching an optimal solution and speed.