多能互补微电网中的虚拟同步发电机（VSG）控制研究

发布时间：2018-05-31 15:37

本文选题：多能互补微电网 + 虚拟同步发电机　；参考：《合肥工业大学》2017年博士论文

【摘要】：近年来,分布式能源在电力系统中渗透率不断增加的同时,也给电力系统的安全稳定运行带来新的影响与挑战。多能互补微电网作为一种新型的分布式发电系统,能够将多种具有互补性的分布式能源集中于同一个系统中,提高整个微电网的能源利用率、供电可靠性和运行经济性。然而,基于电力电子逆变接口的分布式能源不具备旋转惯性和阻尼分量,将对系统的稳定运行造成不利影响。虚拟同步发电机(Virtual Synchronous Generator, VSG)作为一种能够使分布式逆变电源具有与同步发电机相似特性的控制技术,对于提高电力系统的稳定性具有重要的支持作用。针对VSG在多能互补微电网中的控制及其应用问题,本文在国家科技支撑计划项目(863计划)《光伏微电网关键技术研究和核心设备研制》(2015AA050607)等国家项目的支持下,并依托与阳光电源股份有限公司开展的产学研项目《虚拟同步发电机关键技术研究和示范应用》,通过理论研究、实验验证和示范应用等环节系统深入地研究了多能互补微电网的负载适应性、并网适应性、频率稳定性以及运行稳定性的关键技术问题,完成的主要研究工作和成果总结如下:1 )阐述了多能互补微电网的产生背景、运行特征及控制结构,并总结了 VSG的技术分类、应用领域和关键问题。在此基础上,研究了 VSG控制策略,并建立了 VSG的并网和组网小信号模型,分析了虚拟惯性、虚拟阻尼等主要参数对VSG控制稳定性的影响。2)针对多能互补微电网中冲击性、不平衡、非线性负载对电能质量影响的问题,一方面提出了基于输出电压反馈的VSG多环控制策略,利用微分反馈和前馈解耦的复合控制,在负载阶跃扰动条件下实现了良好的动、静态响应特性;另一方面提出了基于级联广义积分器的虚拟阻抗控制策略,在消除输出电流中的直流分量与谐波分量的同时,有效克服了虚拟阻抗引入所带来的谐波放大问题;同时提出了基于谐波虚拟阻抗的电压谐波抑制策略,通过VSG的灵活虚拟阻抗控制,实现了微电网的电压谐波不控、抑制以及拒绝3种模式的选择性抑制,并利用PI+多个谐振电压调节器对多能互补微电网的输出电压不平衡与谐波进行抑制。3 )针对多能互补微电网的频率稳定性问题,提出了基于VSG一次调频与柴油发电机组二次调频的频率分层协调控制策略,兼顾了 VSG与柴油发电机组的动态性能与调频特性;并在分析定参数VSG动态功角响应特性的基础上,提出了自校正VSG控制策略,利用了 VSG的虚拟惯性与阻尼参数能够自校正以及负虚拟惯性的优势,参与系统调频;同时为了抑制柴油发电机组的动态频率波动,研究并提出了基于负载电流微分前馈的VSG频率稳定性控制策略,进一步增加系统的阻尼,减小系统频率的超调量、幅值偏差及其变化率。4 )针对多能互补微电网的并网适应性问题,提出了基于PQ/VSG自适应模式切换的控制策略,通过对比储能变流器分别采用动态改变下垂系数、平移下垂特性曲线以及自适应模式切换算法时的并网功率输出特性,体现了所提控制策略在提高微电网并网适应性方面的优越性。另外,针对多能互补微电网的实际应用,研究了基于VSG的黑启动和运行模式的无缝切换控制策略,并进行了实验验证。5)实验验证与示范应用:一方面搭建了基于VSG的百千瓦级光储柴可靠节能发电系统、基于VSG的兆瓦级光储柴联合发电系统2个多能互补微电网实验平台,对本文所提VSG相关控制策略进行了实验验证;且相关研究成果已在西藏措勤县微网示范电站项目中应用,并参加了现场调试,通过实际工程的运行考核,验证了本文所提VSG部分关键技术的正确性与有效性。
[Abstract]:In recent years, the permeability of distributed energy is increasing in the power system, and it also brings new influence and challenge to the safe and stable operation of the power system. As a new type of distributed generation system, multi energy complementary microgrid can concentrate a variety of complementary distributed energy on the same system and improve the whole micro power. The energy efficiency of the network, the reliability of the power supply and the operation economy. However, the distributed energy based on the power electronic inverter interface does not have the rotating inertia and damping components, which will have a negative impact on the stable operation of the system. The virtual synchronous generator (Virtual Synchronous Generator, VSG) is a kind of distributed inverter power. The control technology similar to synchronous generator plays an important role in improving the stability of the power system. In view of the control and application of VSG in the multi energy complementary microgrid, this paper is in the national science and technology support program (863 plan) "Research on the key technology of photovoltaic microgrid and the development of core equipment" (2015AA050607). Under the support of the national project, and relying on the key technology research and demonstration application of the virtual synchronous generator, which is carried out with the sunshine power Limited by Share Ltd, the system has studied the load adaptability of the multi energy complementary microgrid through theoretical research, experimental verification and demonstration application, and the adaptability of the network and the frequency stability of the multi energy complementary microgrid. As well as the key technical problems of operation stability, the main research work and achievements are summarized as follows: 1) the background, operation characteristics and control structure of multi energy complementary microgrid are expounded, and the technical classification, application fields and key problems of VSG are summarized. On this basis, the VSG control strategy is studied, and the grid of VSG is established. A small signal model is set up to analyze the influence of the main parameters such as virtual inertia and virtual damping on the stability of VSG control.2). In view of the impact, imbalances, and nonlinear loads on the power quality in the multi energy complementary microgrid, a VSG multi loop control strategy based on output voltage feedback is proposed, and the differential feedback and feedforward solution are used. The coupled compound control realizes good dynamic and static response characteristics under the condition of load step disturbance; on the other hand, a virtual impedance control strategy based on cascaded generalized integrator is proposed, which eliminates the harmonic amplification problem brought by the introduction of virtual impedance, while eliminating the DC component and harmonic component in the output current. The voltage harmonic suppression strategy based on the harmonic virtual impedance is proposed. Through the flexible virtual impedance control of VSG, the voltage harmonic uncontrol of the micro grid is realized, and the selective suppression of the 3 modes is suppressed and rejected, and the output voltage imbalance and the harmonic of the multi energy complementary microgrid are suppressed by the PI+ multiple resonant voltage regulator.3. In view of the frequency stability of multi energy complementary microgrid, a frequency stratified control strategy based on VSG primary frequency modulation and two frequency modulation of diesel generating set is proposed. The dynamic performance and frequency modulation characteristics of VSG and diesel generator set are taken into account, and the self-tuning VSG is proposed on the basis of the analysis of the dynamic reactive power angle response characteristic of the fixed parameter VSG. The control strategy takes advantage of VSG's virtual inertia and damping parameters to self-tuning and negative virtual inertia, and participates in the system FM. At the same time, in order to suppress the dynamic frequency fluctuation of the diesel generator set, a VSG frequency stability control strategy based on the load current differential feedforward is proposed, which can further increase the damping of the system and reduce the damping of the system. The overshoot of the system frequency, amplitude deviation and its change rate.4) proposed a control strategy based on PQ/VSG adaptive mode switching in view of the adaptability of the multi energy complementary microgrid. By comparing the dynamic change droop coefficient, the ptosis characteristic curve and the adaptive mode switching algorithm. The power output characteristic shows the superiority of the proposed control strategy in improving the adaptability of the micro grid connected to the grid. In addition, the seamless handoff control strategy based on the VSG based black start and operation mode is studied for the practical application of the multi energy complementary microgrid, and the experimental verification and demonstration application of the experimental verification.5) are carried out. On the one hand, the base is built. Based on the 2 multi energy complementary microgrid experimental platform of VSG based MW light storage and firewood combined power system, the VSG related control strategy of this paper is verified experimentally, and the related research results have been applied in the project of the micro network demonstration power station in Cuoqin County, Tibet, and have participated in the field debugging. The correctness and effectiveness of some key technologies of VSG are verified through the actual operation evaluation.
【学位授予单位】：合肥工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TM727;TM31

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