基于MPC的耦合电感飞跨电容双向DC/DC变换器功率均衡解耦控制策略

耦合电感功率变换器因耦合电感阻抗、电感值等参数差异易导致功率不均衡。针对耦合电感飞跨电容双向DC/DC变换器,提出一种基于模型预测控制（MPC）的功率均衡解耦控制策略。通过对变换器原理进行分析,建立基于电感电流解耦的数学模型,得到包括电感电流和飞跨电容电压等6个控制变量的解耦控制方法。在此基础上,提出基于MPC的功率均衡解耦控制策略。同时,为降低MPC算法的运算负荷,根据解耦控制模型重构模型预测价值函数,实现各控制变量独立动态寻优,使系统能在稳定控制输出电压及飞跨电容电压的同时,实现两相耦合电感的功率均衡控制。最后,通过理论分析及实验对所提策略进行有效验证。     

基于反演控制的DC-MMC双闭环解耦控制策略研究

随着大量分布式电源投入电网,分压式模块化多电平直流变换器（DC-MMC）得到广泛应用。针对模块化多电平变换器控制系统多输入多输出、强耦合非线性的特点,推导变换器拓扑数学模型,建立此类拓扑的电流和能量模型,提出一种基于反演控制的双闭环解耦控制方法。通过消除系统之间的耦合,采用模型反演理论对所建解耦模型进行控制,实现桥臂电流保持稳定并交流分量最小化,增强系统的抗扰动能力。在Matlab/Simulink中搭建DC-MMC双闭环模型,分析表明闭环控制模型具有良好的跟踪效果和调控特性,验证了提出的控制策略控制桥臂电流及高低压侧电流的可行性和有效性,为解耦控制的应用提供了参考依据。     

基于动态相对增益的逆变器耦合评价与解耦方法

针对逆变器的功率耦合现象,理论分析逆变器功率耦合的根本原因,将控制论中的动态相对增益法应用于分布式发电系统中,提出一种全频域内量化评价逆变器功率耦合程度的方法,实现控制量参数和被控量参数的正确配对。基于对角形矩阵的功率解耦控制方法,改进传统的下垂控制策略,配合电压电流双闭环控制及前馈解耦,实现了逆变器输出有功功率、无功功率的独立控制。最后,具体算例验证了基于动态相对增益的功率耦合评价方法的合理性,仿真验证了基于对角形矩阵的功率解耦控制方法的可行性。     

基于运行模式识别的球磨机自适应解耦模糊控制与仿真

针对目前球磨机系统控制存在的不足,提出了一种基于运行模式识别的球磨机系统自适应模糊解耦控制算法.首先,分析了球磨机系统的动态特性,并结合某电厂测试试验,得到了球磨机系统的数学模型;其次,采用LS-SVM算法对球磨机系统的运行状态进行识别和分类;对于正常工况,针对耦合回路,设计了自适应解耦模糊控制器对球磨机进行控制;对于异常工况,给出了相应的控制策略.最后对正常工况下的自适应解耦模糊控制算法进行了仿真研究.仿真结果表明,该算法能够有效地实现球磨机系统运行工况模式识别和耦合回路的解耦控制,控制系统具有良好的动态性和鲁棒性.     

微网双向变流器的解耦控制策略研究

在微电网中,双向变流器作为核心组网装置,起到稳定接入点电压,降低网损率和提高功率因数的作用。但是在同步旋转坐标系下,双向变流器是一个强耦合、非线性的系统,因此需要对其进行解耦控制,以保证并网电流能够快速无差地跟踪给定信号。研究双向变流器的解耦控制策略,对其在同步旋转d-q坐标系下的数学模型进行了推导和分析,在此基础上采用PI控制和前馈控制相结合的解耦控制方法,将原系统进行线性化解耦,消除了有功与无功电流的耦合,实现系统的解耦控制。实验结果表明,所提解耦控制策略能够降低稳态跟踪误差和总谐波失真,具有较好的控制性能。     

双馈异步风机非线性低电压穿越控制策略研究北大核心CSCD

针对双馈风力发电机组对低电压穿越能力要求较高的问题,提出一种新型的内电势串级比例积分控制策略。控制器包括电压和功率两个串级控制回路,通过调节内电势dq轴分量,实现双馈风机有功、电压控制,进而完成对有功功率和无功功率的解耦。为提高双馈风机故障穿越能力,引入变增益功角补偿模块,实现故障过程中对功角的完全控制。仿真对比结果验证了该控制策略降低故障中双馈风机端电压跌落程度的有效性。     

基于双序前馈解耦的光伏逆变器并网控制策略

为了消除三相不平衡LCL型光伏并网逆变器在同步旋转坐标下耦合项对电流控制性能的影响,该文提出适用于逆变侧电流反馈的双序前馈解耦的方法。通过双旋转剔除耦合项中负序直流量,使用正序直流量进行前馈解耦,实现电网电压和变换耦合项对控制环路的零干扰。在PI控制的基础上加入重复控制,抑制死区效应,降低并网电流谐波含量。通过仿真和实验,验证所提控制策略的有效性。     

模块化多电平变换器的非线性控制

针对模块化多电平变换器(modular multilevel converter,MMC)多变量、非线性、强耦合的特点,提出了一种基于反馈线性化理论的滑模变结构控制策略。首先,建立MMC的非线性状态函数模型,利用输出重定义的反馈线性化理论,将其转化为线性模型,实现解耦控制。在解耦后的线性模型基础上,设计滑模变结构控制器。仿真结果证明,该文的控制策略具有良好的动态调节特性和稳态特性,且对系统参数偏差具有鲁棒性。     

变速恒频双馈风力发电机有功、无功解耦控制研究与实现

双馈发电机有功功率、无功功率解耦控制是变速恒频风力发电系统的关键技术,在分析双馈发电机有功功率、无功功率解耦控制规律的基础上,给出了基于定子磁场定向控制策略的实现方案,然后利用Matlab工具对该控制方案进行了仿真研究,最后设计和构造了基于TI公司MS320F2407DSP的变速恒频双馈风力发电机有功功率、无功功率解耦控制实验系统,仿真和实验结果表明该控制策略能够有效地实现双馈发电机功率的解耦控制,为兆瓦级变速恒频双馈风力发电机组励磁变换器的研制奠定了基础。     

基于线性扩张状态观测器的无刷双馈电机控制

无刷双馈电机内部存在复杂的非线性耦合关系,针对这些内部耦合项和外部扰动在实际中难于测得的特点,提出一种基于线性扩张状态观测器(linear extended state observer,LESO)的控制方法。首先建立无刷双馈电机在同步坐标系下的复变量模型,在此基础上分别对磁链和转速设计扩张状态观测器来估计系统的内部耦合和外部扰动并对它们做出补偿,进而实现系统的解耦控制,该控制策略不依赖系统的模型和参数。仿真对比结果表明,扩张状态观测器能够快速精确估计总扰动并做出补偿,具有很强的抗扰能力并可实现系统解耦。该控制器比传统控制器明显改进了系统的调节特性和鲁棒性。     

基于通用虚拟电厂应用系统的分布式水电资源规划

为应对分布式小型水电机组的大规模应用给电力系统尤其是配电侧电压控制带来的巨大冲击,引入了通用虚拟电厂技术,并基于面向服务架构理论,对通用虚拟电厂技术存在的松耦合问题、适用性问题、可交换策略及安全性问题提出了改进策略,形成针对分布式小型水电优化调度的通用虚拟电厂应用系统模型。选取某地区小型水电机组群进行分析,结果表明,通用虚拟电厂应用系统可有效调节含分布式小型水电的电力系统配电侧电压,降低系统日负荷峰谷差,维持电力系统的平衡运行。     

Optimal dispatch strategy in remote hybrid power systems

For small villages in developing countries, local stand-alone power systems are often more cost-effective than utility grid extension. Various combinations of wind turbine generators, photovoltaic arrays, diesel gensets, and batteries—remote hybrid power systems—may be preferred to diesel-only systems. Dispatch strategy is the aspect of control strategy that pertains to energy flows among components. In systems with both batteries and diesel genset(s), dispatch affects the life-cycle cost through both the fuel usage and the battery life. In this study, dispatch strategies are compared using (1) an analysis of cost trade-offs, (2) a simple, quasi-steady-state time-series model, and finally (3) HYBRID2, a more sophisticated stochastic time-series model. An idealized predictive dispatch strategy, based on assumed perfect knowledge of future load and wind conditions, is developed and used as a benchmark in evaluating simple, non-predictive strategies. The results illustrate the nature of the optimal strategy and indicate that one of two simple diesel dispatch strategies—either load-following or full power for a minimum run time—can, in conjunction with the frugal use of stored energy (the Frugal Discharge Strategy), be virtually as cost-effective as the Ideal Predictive Strategy. The optimal choice of these two simple charging strategies is correlated to three dimensionless parameters, yielding a generalized dispatch design chart for an important class of systems.     

A comparison of real-time energy management strategies of FC/SC hybrid power source: Statistical analysis using random cycles

This paper presents a comparative study of two promising real-time energy management strategies for fuel cell electric vehicle applications: adaptive equivalent consumption minimization strategy (A-ECMS), and stochastic dynamic programming (SDP). An off-line algorithm –classic dynamic programming - provides reference results. On-line and off-line strategies are tested both in simulation and using a dedicated test bench completely consistent with an electric scooter powertrain.The hybrid power source combines a fuel cell, a supercapacitor pack and two related power converters. The system model is carefully calibrated using experimental data. This allows meaningful identification of parameters of the various strategies. The model data is determined using a motorcycle certification driving cycle.The robustness of each strategy is then analyzed using a large number of random driving cycles. Experimental and simulation results show that a specific SDP approach, based on Markov chain modeling, has the best overall performance in real-world driving conditions. It achieves the minimum average hydrogen consumption while respecting the state-sustaining constraint. Conversely, the A-ECMS results lack robustness and show poor performance indexes when facing unknown real world power demand profile. In conclusion, the present results indicate SDP is an interesting approach for future hybrid source energy allocation.     

Stabilizing controls for a doubly fed synchronous-induction machine

The stability of a doubly-fed synchronous-induction machine is investigated through small as well as large perturbation models. Two stabilizing control strategies have been proposed for the small perturbation bilinear model. The first is based on quadratic bilinear regulator theory, and the second provides a suboptimal control based on minimization of time. The responses are compared with the uncontrolled ones as well as those with conventional linear regulator control. While both the proposed strategies stabilize the system, the minimum-time suboptimal control is found to be superior     

Analysis of impact of grid‐connected wind power on small signal stability

The power system small signal stability analysis considering wind generation intermittence is studied comprehensively in this paper. The modelling of doubly‐fed induction generator (DFIG) involving the converters with application of stator flux‐oriented vector control strategy is addressed briefly. In order to reveal how the intermittent nature of wind power affects the operating behaviour of an existing power system, a probabilistic small signal stability analysis method based on Monte Carlo simulation technique is proposed to explore and exploit the impact of intermittent grid‐connected wind power on small signal stability. The IEEE New England test system is applied as benchmark to verify the proposed model and approach. Total 3 scenarios are elaborately designed to figure out the potential relationship between the small signal stability indices and the wind generation intermittence. Finally, some preliminary conclusions and comments were drawn based on the numerical simulation results. Copyright © 2010 John Wiley & Sons, Ltd.     

弯曲和质量失衡对转子弯扭耦合振动影响的探讨

建立基于单质量柔性转子模型的弯扭耦合振动数学模型,模型中考虑了质量失衡及转子弯曲等因素,对数学模型进行的数值计算结果表明质量失衡和弯曲对转子的弯扭耦合振动具有重要的影响,一定程度的转子质量失衡是转子发生弯扭耦合振动的必要条件,仿真计算表明当偏心率及弯曲度大到一定程度时,转子转速会出现两个耦合区,质量偏心与转子弯曲的相位差会影响耦合区的大小及耦合区内的耦合振动,转子扭转刚度较大时的耦合效应较弱。     

Variable structure TITO fuzzy-logic controller implementation for a solar air-conditioning system

The design and implementation of a Two-Input/Two-Output (TITO) variable structure fuzzy-logic controller for a solar-powered air-conditioning system is described in this paper. Two DC motors are used to drive the generator pump and the feed pump of the solar air-conditioner. The first affects the temperature in the generator of the solar air-conditioner, while the second, the pressure in the power loop. The difficulty of Multi-Input/Multi-Output (MIMO) systems control is how to overcome the coupling effects among each degree of freedom. First, a traditional fuzzy-controller has been designed, its output being one of the components of the control signal for each DC motor driver. Secondly, according to the characteristics of the system’s dynamics coupling, an appropriate coupling fuzzy-controller (CFC) is incorporated into a traditional fuzzy-controller (TFC) to compensate for the dynamic coupling among each degree of freedom. This control strategy simplifies the implementation problem of fuzzy control, but can also improve the control performance. This mixed fuzzy controller (MFC) can effectively improve the coupling effects of the systems, and this control strategy is easy to design and implement. Experimental results from the implemented system are presented.     

水资源管理中的水-能源-经济耦合关系

为研究水资源、能源与社会经济之间的耦合协调关系及时序变化特征,基于水资源管理"三条红线"制度的内涵,建立了水资源-能源-经济系统的耦合协调评价指标体系,利用耦合协调模型定量分析整个系统的协调发展水平及子系统相互之间的耦合关系。以山东省为例,分析其2005～2016年水-能源-经济系统的耦合协调发展水平及变化特征。发现山东省水资源、能源与社会经济一直处于高水平耦合阶段,相互作用程度显著;耦合协调度呈波动式上升状态,从勉强协调发展类升至中级协调发展类,但三者之间仍存在较大的耦合协调空间,故应提高水资源与能源的开发利用效率,加强环境保护力度,促进区域经济的协调可持续发展。     

综合能源系统运行优化设计与运行策略研究

综合能源系统能整合协调各异质能源,是提高能源利用率和降低运行费用的有效途径。提出了两种运行策略及一种基于穷举法的优化策略方法,建立了包括小型燃气轮机系统、地源热泵、电制冷机、吸收式制冷机、换热器的综合能源系统能量转换模型。在案例研究中,提出了以典型日费用最小为目标的综合能源系统优化方案,对以电定热、以热定电两种运行策略下的场景进行了优化分析,确定设备的最佳容量和运行参数,给出了运行策略对比分析结果。结果表明：以电定热策略的整体经济性优于以热定电策略约10%;与传统供能系统在经济性上的适用性进行对比发现,综合能源系统成本节省比例在5%～30%之间。     

含旋转备用的独立风光储系统控制与仿真

鉴于独立风光储系统配备一定容量的旋转备用的必要性,利用小型柴油发电机作为独立风光储系统的旋转备用,在PSCAD平台上建立了独立风光储系统的仿真模型,并提出将风力发电和光伏发电系统均采用恒功率(PQ)控制、蓄电池和超级电容器的混合储能系统作为主控制器采用恒压恒频(V/f)控制的控制策略,EMTDC仿真结果验证了将旋转备用控制引入独立风光储系统的正确性和有效性。