微电网复合储能柔性控制技术与容量优化配置

发布时间：2018-04-19 13:33

本文选题：微电网 + 复合储能　；参考：《山东大学》2014年博士论文

【摘要】：近年来,因面临化石能源日渐短缺与枯竭以及全球气候变化等严峻现实问题,作为分布式可再生能源的有效组织形式,微电网技术在国内外得到前所未有的关注。储能作为微电网的重要组成部分,在微电网稳定控制、平抑可再生能源波动、电能质量补偿、削峰填谷、应急供电等领域可为微电网提供关键技术支撑。然而,受限于储能技术水平发展的掣肘,单一储能往往难以满足微电网内多种不同需求,发展复合储能技术,是目前在经济、技术上较为可行的解决方案。研究微电网复合储能关键技术,具有重要的现实意义和应用价值。本文着眼于微电网对储能技术的多种典型需求,针对微电网中复合储能的柔性控制与容量配置开展探索和创新研究,重点解决复合储能的多端口接入、储能变换器可靠容错运行、储能对微电网的关键支撑作用等基础性问题,在此基础上探讨微电网复合储能容量的多目标优化配置技术。以多绕组高频变压器为基础,构建了复合储能的多端口统一接入拓扑,揭示了端口间的功率传输规律及影响机制；基于超级电容和蓄电池相融合的三端口全桥复合储能等效电路,推导出三端口复合储能的平均电流小信号分析模型,并藉此获得三端口复合储能定功率传输策略；针对超级电容端口电压随储能容量波动较大的特点,研究得到一种异步占空比移相PWM算法,实现多端口变换器在功率传输过程中端口电压的匹配,可有效改善传输效率。上述研究为复合储能整体接入微电网所需的底层功率传输控制提供了技术基础。微电网储能装置的可靠性很大程度上取决于储能变换环节。在兼顾经济成本和控制性能的前提下,针对潜在的储能变换故障,研究三相四开关储能容错拓扑,并给出容错切换的临界条件和切换准则。准确快速地获取储能变换器的故障信息是实现故障容错的前提,针对建模中的故障信息丢失问题,引入电路状态逻辑构建了储能变换器混杂系统动态(HSD)模型,藉此获得一种基于电流状态残差演变特征的储能变换器故障诊断方法,可显著提高故障诊断的快速性。针对四开关变换器的内在缺陷,基于等效阻抗理论揭示了输出阻抗、逆变频率和辅助电容差异对输出不平衡的内在作用机制,根据调制信号与空间电压矢量作用时间的关联规律,推导出一种实现直流中点电位偏差前馈补偿的等效SVPWM控制方法,显著提高了四开关储能变换器容错运行的平衡度。可对微电网电能质量进行补偿的电力有源滤波器(APE),存在功能单一、造价较高等问题,而四开关储能变换器因减少了功率器件和辅助装置,在低成本功率变换领域的应用前景较好。为此,本文开展了低成本三相四开关储能型APF应用技术研究。推导出一种基于电源电流跟踪的微电网谐波和无功直接补偿策略,因无需检测谐波,可有效降低四开关APF的实现难度。进一步研究了电压跌落引起的微电网不平衡对四开关APF的影响机制,推导出基于线电压矢量合成的四开关APE电流参考值生成策略,以适应微电网中的特殊不对称情况。四开关储能型APF可对微电网提供多种柔性支撑。针对四开关储能型APF工作模式的自适应切换,借助坐标变换推导出不同模式下的指令电流算式,并给出切换控制的边界条件；针对四开关APF的物理实现,给出了APF关键控制参数的取值准则及定量计算方法,并得到一种基于周期积分的单相软件锁相方法,实现了对电源电流的精确滞环跟踪补偿。微电网复合储能容量的配置多依赖于工程经验,缺乏理论指导和定量评估标准,为此,本文深入研究了微电网复合储能容量的多目标优化配置技术。构建了以投资成本最低、功率平衡最优、可再生能源发电功率波动最小为目标的复合储能容量配置多目标优化数学模型,从滤波系数、功率限幅、储能充放电管理等角度阐明了影响复合储能优化效果的关键因素；提出一种基于目标函数适应度离差均值排序的子目标函数权重确定方法,用以重组目标函数,可有效降低粒子群优化求解算法的实施难度；为评估多目标最优解的有效性,定义了可再生能源波动系数和供求平衡匹配系数,可实现优化效果的定量评估。针对超级电容和蓄电池构成的典型复合储能,就容量的多目标优化配置开展算例分析,给出了典型目标函数的建立方法以及优化算法实现流程,量化比较了复合储能和单一储能的容量多目标优化配置效果,表明复合储能容量优化配置的合理性。基于构建的微电网实验平台,进一步开展了复合储能柔性控制实验研究。研制了三端口复合储能全桥变换器、三相四开关储能容错装置、储能型四开关APF等实验样机,给出了关键参数的优化结果和软硬件实现方法,重点开展了复合储能定功率控制、容错判断及切换、直接电流滞环跟踪、电能质量统一补偿、锁相跟踪等实验研究,验证了本文理论与方法的有效性。本文研究结果可为微电网复合储能装置的拓扑设计和工程应用提供理论基础和技术依据。
[Abstract]:In recent years , the micro - grid technology has received unprecedented attention as an effective organization form of distributed renewable energy because of the shortage and depletion of fossil energy and global climate change . As an important part of the micro - grid , the energy storage is a key component of the micro - grid . However , it is often difficult to meet the many different needs of the micro - grid in the fields of micro - grid stability control , flat - peak power supply and other fields . However , the development of the composite energy storage technology is a feasible solution in the economy and technology . It is of great practical significance and application value to study the key technology of composite energy storage of micro - grid .

In this paper , based on the typical demand of micro - grid for energy storage technology , the research on flexible control and capacity allocation of composite energy storage in micro - grid is studied , and the basic problems such as multi - port access of composite energy storage , reliable fault - tolerant operation of energy storage transformer and key supporting role of energy storage on micro - grid are emphatically solved , and the multi - objective optimization collocation technology of micro - grid composite energy storage capacity is discussed .

Based on the multi - winding high - frequency transformer , a multi - port unified access topology with composite energy storage is constructed , and the power transmission law and influence mechanism among the ports are revealed .
Based on the three - port full - bridge composite energy storage equivalent circuit fused by the super capacitor and the storage battery , the average current small signal analysis model of the three - port composite energy storage is deduced , and the three - port composite energy storage constant - power transmission strategy is obtained .
According to the characteristics of the super capacitor port voltage fluctuation with the storage capacity fluctuation , an asynchronous duty cycle phase shift PWM algorithm is developed to realize the matching of the port voltage in the power transmission process of the multi - port converter , which can effectively improve the transmission efficiency . The research provides a technical foundation for the control of the bottom power transmission required by the composite energy storage integrated access micro - grid .

This paper studies three - phase four - switch energy - storage fault - tolerant topology and gives the critical condition and switching criterion of fault - tolerant switching .

This paper studies the application prospect of low - cost three - phase four - switch energy - storage APF in low - cost power conversion .

The four - switch energy storage type APF can provide various flexible supports to the micro - grid . According to the self - adaptive switching of the four - switch energy storage type APF working mode , the instruction current formula in different modes is derived by means of coordinate transformation , and the boundary conditions of the switching control are given ;
According to the physical realization of the four - switch APF , the value criterion and the quantitative calculation method of the key control parameters of APF are given , and a single - phase software phase locking method based on the periodic integral is obtained , and the accurate hysteresis tracking compensation for the power supply current is realized .

In this paper , the multi - objective optimization mathematical model of composite energy storage capacity with minimum investment cost , optimal power balance and minimum power fluctuation of renewable energy is studied . The key factors that affect the optimization effect of composite energy storage are expounded from the angle of filter coefficient , power limit , energy storage and discharge management .
This paper presents a method for determining the weight of sub - objective function based on objective function fitness deviation mean ordering , which is used to reconstruct the objective function , which can effectively reduce the implementation difficulty of the particle swarm optimization solution algorithm ;
In order to evaluate the effectiveness of the multi - objective optimal solution , a quantitative evaluation of the optimization effect can be realized by defining the matching coefficients of the renewable energy fluctuation coefficient and the supply and demand balance .

Aiming at the typical composite energy storage of super capacitor and storage battery , an example analysis is carried out on the multi - objective optimal configuration of capacity , the establishment method of the typical objective function and the realization flow of the optimization algorithm are given , and the optimization collocation effect of the capacity of the composite energy storage and the single energy storage is quantified and compared , and the rationality of the optimal configuration of the composite energy storage capacity is shown .

Based on the constructed micro - grid experiment platform , the experimental research on the flexible control of composite energy storage is carried out . The experimental prototype of three - port composite energy - storage full - bridge inverter , three - phase four - switch energy - storage fault - tolerant device and energy - storage type four - switch APF is developed . The key parameters optimization results and the software and hardware implementation method are given . The experimental research on complex energy storage constant - power control , fault - tolerant judgement and switching , direct current hysteresis loop tracking , power quality unified compensation and phase lock tracking are emphatically carried out , and the validity of the theory and method is verified .

The results of this paper can provide theoretical basis and technical basis for topology design and engineering application of micro - grid composite energy storage device .

【学位授予单位】：山东大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM727

【参考文献】