集中控制式微网系统的稳态建模与运行优化

包含多种分布式能源和可控负荷、作为一个可控整体的微网具有灵活的运行方式和可调度性能,既可与主网并网运行,也可以孤岛形式自主运行.在建立各种分布式能源稳态模型的基础上,建立了集中控制模式下的微网优化调度模型,提出了运行和折旧成本最低、环境和综合效益最高等优化目标函数.以一个微网系统为例,讨论了所采用的交互式运行控制策略、优化目标函数以及主网电价类型的不同对系统运行优化结果的影响,验证了所建立的模型的合理性.     

Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach

DC-DC converter-based multi-bus DC microgrids (MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method.

     

含考虑IDR的冷热电联供微网的主动配电网经济优化调度

多个冷热电联供微网接入主动配电网后,微网和配网作为不同利益主体,系统经济调度更具复杂性。为保护各自隐私,提出了一种含冷热电联供微网的主动配电网经济优化调度模型。运用机会约束规划来处理冷热电联供微网群中新能源及冷热电负荷的随机性,采用分布式建模方法,以各自区域的运行成本最小化为目标,运用目标级联法来并行求取各自区域的最优经济调度结果。同时在冷热电联供微网用户侧引入综合需求响应(Integrated DemandRespond,IDR),有利于降低供用能成本。通过改进的IEEE33节点系统算例验证表明,引入IDR后,能有效降低系统运行成本,运用目标级联法能在保护各自区域隐私的基础上求取主动配电网和冷热电联供微网各自最优的经济调度结果。     

交直流混合微网中双向接口变换器控制综述

在交直流混合微网中,双向AC/DC接口变换器连接交直流母线实现子网之间的能量双向流动,其控制策略直接影响交直流混合微网的稳定运行。根据微电网的运行模式,接口变换器的控制可以分为并网控制和孤岛控制两大类。首先对交直流混合微网的结构进行了分析和讨论,随后分别介绍了并网模式和孤岛模式下单台接口变换器以及多台并联接口变换器的控制策略。最后对当前主要的控制方法进行了总结,并对未来双向接口变换器的研究方向进行了展望。     

基于序列运算的风光储混合微电网可信容量评估

以含风光储的交直流混合微电网为研究对象,通过聚类分析方法对气象条件进行分类,搭建风光储出力概率模型并进行序列化.提出一种序列运算方法计算交直流混合微电网用电不足期望值,从而迭代求得可信容量,针对风光装机容量配比以及直流负荷敏感度对可信容量的影响进行了分析,并将计算结果与蒙特卡洛法进行了对比,验证该文所提方法的正确性与有...     

适用于孤岛微电网的电压型虚拟同步发电机自适应惯性控制与频率恢复控制

孤岛微电网惯性水平低,频率稳定问题显著。基于此,提出了适用于孤岛微电网电压型虚拟同步发电机(voltage-controlled virtual synchronous generators,VSGs)的自适应惯性与频率恢复控制方法,用于孤岛微电网频率稳定性提升。在自适应惯性控制方面,利用转速偏差及其变化率刻画频率动态过程,分别构建其与虚拟惯性的关系;利用双曲正弦函数放大虚拟惯性对转速偏差及其变化率的灵敏度,提高控制的敏感性;引入sigmoid函数,限制虚拟惯性调节范围,抑制控制过程中VSG输出功率的振荡。在频率恢复控制方面,从有功功率供需平衡的角度出发,将频率恢复问题转化为全网有功再平衡问题;利用各台VSG的频率偏差及其变化率估计全网有功再平衡量,并按容量分配每台VSG承担的全网有功再平衡量,实现功率均分。通过不同情境对所提方法进行仿真测试,结果验证了其有效性。     

考虑热泵负荷和分布式光伏的配微网协调调度

随着农村清洁供热改造以及城镇分布式光伏建设的不断推进,配电网中出现了大量农村微电网。分布式光伏的强随机性和波动性给电网的运行调控带来了诸多挑战,电网面临剧烈的潮流波动和严重的电压越限等问题。首先,构建了计及热泵、光伏和储能的配微网分解协调模型,其中热泵用等效状态空间模型描述;然后,提出一种配微网有功无功协调优化方法,并采用改进的Benders分解算法进行求解;最后,在D141-M4算例系统上进行了算例测试。测试结果表明,所提方法可以在保证用户舒适度的前提下,有效降低电网峰值负荷,并提升电压安全水平。     

A self-interested distributed economic model predictive control approach to battery energy storage networks

In this work, a dissipativity based distributed economic model predictive control (DEMPC) approach is developed for the operation of battery energy storage (BES) networks in residential microgrids. With the presence of a microgrid power market (MPM), control of the BES systems is formulated as a self-interested distributed control problem, as individual DEMPC controllers minimize their local economic cost functions based on the price prediction of MPM. Due to the intermittent nature of photovoltaic (PV) power generations and load demands, the DEMPC without proper coordination or constraints may lead to excessive energy trading and price oscillations in MPM. To solve this problem, dissipativity theory with dynamic supply rates is adopted in this paper to deal with the interactions between individual users and the MPM. The microgrid-wide performance requirement of attenuation of the net power fluctuations with respect to time-varying PV generation and demands, is converted into the dissipative trajectory constraints imposed on individual DEMPC controllers. The proposed approach is scalable as it does not require online iterative optimizations across the controller network. A case study is presented to illustrate the proposed method.     

微电网二次频率/电压控制器的反馈线性化设计及分布式实现

针对以微型同步发电机组为二次控制主体的微电网,提出了一种在孤岛运行模式下的二次频率/电压分布式控制策略。首先,利用反馈线性化方法,设计了一种适用于微型同步发电机的二次频率/电压控制器,可消除由于微型同步发电机组一次控制导致的系统频率与电压偏差。其次,基于多代理系统理论,提出了一种分布式控制策略。所提出的频率/电压控制器只需要交换在通信有向图上的邻居节点频率/电压信息,不依赖中央控制器和复杂通信网络,提高了微电网的可靠性,同时可实现微型同步发电机有功出力按额定比分配。最后,在某一实际的微电网上验证了提出的二次控制策略的有效性。     

户用微电网能量调度日前计划研究

针对户用微电网能量管理实际情况,建立了基于储能水平控制的户用微电网日前用电计划优化调度模型,并给出了基于矩阵实数和0、1整数的混合编码方式的遗传算法的求解方法。通过控制储能单元的储能水平、合理安排可时移家用负荷的用电时间,使得家庭用电成本最小、可再生能源发电利用率最大。最后通过算例验证了所提出的模型与算法的可行性和有效性,该模型与方法不仅能够降低用户用电成本而且对上级电网起到削峰填谷的作用。