多功能并网逆变器及其微电网应用

发布时间：2018-06-16 12:34

本文选题：微电网 + 多功能并网逆变器　；参考：《浙江大学》2014年博士论文

【摘要】：全球能源危机和环境问题的不断加剧,激励了风光等可再生能源并网技术的快速发展。作为传统大规模集中式风光电站的重要补充,可再生能源的分布式发电技术引起了国内外的广泛关注。微电网作为一种特殊的分布式发电系统,是连系电网和可再生能源的重要桥梁和纽带,可以有效降低可再生能源并网单元对电网的冲击,提高供电可靠性和电能质量,受到了普遍的青睐。然而,微电网中的并网逆变器大多只能刚性地向电网注入纯正弦的基波有功电流,暴露出了诸多技术局限,难以满足众多的新兴技术需求。其中,电能质量治理、独立自治运行、谐波谐振抑制等并网逆变器的辅助服务需求最受瞩目。功能更加多样、控制更加灵活的多功能并网逆变器成为微电网领域极具创新性和挑战性的研究方向之一。本文以微电网中多功能并网逆变器的技术需求为契机,系统深入地研究了多功能并网逆变器向微电网提供辅助服务功能的若干关键技术问题,获得了一些创新性研究成果。 1、针对微电网电能质量的主动治理,详细研究了多功能并网逆变器的“并网发电与电能质量统一控制”技术,实现对微电网内无功、负序和谐波负荷电流的补偿。一方面,对于单台多功能并网逆变器的电能质量优化补偿控制,提出了微电网电能质量综合评估的概念,并在此基础上提出了相应的控制策略,利用多功能并网逆变器的功率裕量实现微电网电能质量的定制。针对三相组式和三相两电平两大类多功能并网逆变器,进行了详实的仿真和实验研究,验证了多功能并网逆变器在优化地提供电能质量治理辅助服务,以及有目标地定制微电网电能质量方面的可行性和有效性。另一方面,对于多台多功能并网逆变器之间的电能质量协调控制,基于电导电纳限幅控制和下垂控制,分别提出了两种微电网谐波和无功电流的无互联线分摊控制策略,以有效地组织和协调微电网内相对分散的多台多功能并网逆变器,独立自治地参与微电网电能质量的治理。严格的实验结果验证了所提的两种控制方案在协调微电网内多台多功能并网逆变器,主动参与微电网电能质量治理方面的正确性和有效性,以及其适应微电网“即插即用”、“在线热插拔”等功能需求的能力。 2、针对微电网并网逆变器的独立自治运行,重点研究了多功能并网逆变器的“虚拟同步发电机”控制技术,利用多功能并网逆变器模拟传统同步发电机的同步机制和摇摆方程,虚拟惯性和阻尼,实现其对1Hz级的摇摆方程等机电暂态过程的控制能力。同时,还可以模拟同步发电机的调压和调频特性,向电网提供电压和频率支撑的辅助服务。系统地研究了虚拟同步发电机控制技术的数学模型,并深入讨论了控制器参数对虚拟同步发电机性能的影响,以及虚拟惯性和阻尼参数的整定策略。此外,还详细阐释了虚拟同步发电机储能单元的优化配置方法。通过所研究的虚拟同步发电机控制策略,可以使得多功能并网逆变器具有更多的柔性,对电网更加友好。利用仿真和实验结果验证了所提模型和控制方法的正确性和有效性。 3、针对含多台并网逆变器的微电网的谐波谐振及抑制,重点研究了多功能并网逆变器的“输出阻抗重塑”技术,通过重塑多功能并网逆变器的输出阻抗,可以对微电网几kHz处的谐波谐振频率分量加以有效的阻尼。从开环等效电路和闭环等效电路两个角度,详细阐释了微电网中多台并网逆变器谐波谐振的机理,并在此基础上提出了多功能并网逆变器输出阻抗重塑的概念,通过控制多功能并网逆变器输出阻抗,向微电网注入更多的虚拟电阻分量,从而有效地抑制微电网内的谐波谐振。仿真和实验结果验证了所提输出阻抗重塑技术的可行性和有效性。本文针对微电网中并网逆变器的电能质量治理、独立自治运行和谐波谐振抑制三大关键技术需求,分别从针对谐波负荷电流的“并网发电与电能质量统一控制”技术、针对几Hz频段的“虚拟同步发电机”技术和针对几kHz频段的“输出阻抗重塑”技术的角度给出了相应的应对措施,使得并网逆变器在性能上更加灵活,在功能上更加多样,并能向微电网提供更加丰富的辅助服务,具有很好的研究价值和应用前景。当然,随着技术的发展,并网逆变器(甚至是其他并网变流器)还可能为电网提供更加丰富的辅助服务,这有待进一步的研究。
[Abstract]:The growing global energy crisis and environmental problems have stimulated the rapid development of renewable energy grid technology, such as scenery. As an important supplement to the traditional large-scale centralized wind power plant, the distributed generation technology of renewable energy has aroused widespread concern at home and abroad. As a special distributed generation system, the micro grid is connected. The important bridge and link of power grid and renewable energy can effectively reduce the impact of the renewable energy grid unit on the power grid and improve the power supply reliability and power quality. However, most of the grid connected inverters in the microgrid can only inject pure sine basic active current into the power grid. It is difficult to meet many new technology needs. Among them, the demand for auxiliary services of grid connected inverters, such as power quality control, independent autonomous operation, harmonic resonance suppression, is the most attractive. The multi-function and multi function grid connected inverters with more versatile functions and more flexible control have become the most innovative and challenging research direction in the field of microgrid. One of.
In this paper, based on the technical requirements of multi-function grid connected inverters in microgrid, this paper systematically studies some key technical problems of providing auxiliary services to microgrid by multi-function grid connected inverters, and obtains some innovative research results.
1, in view of the active control of the power quality of the microgrid, the "unified control of grid connected generation and power quality control" for multi-function grid connected inverters is studied in detail, which can compensate for the reactive power, negative sequence and harmonic load current in the microgrid.
On the one hand, for the power quality optimization compensation control of the single multi-function grid connected inverter, the concept of the comprehensive evaluation of the power quality of the microgrid is proposed. On this basis, the corresponding control strategy is put forward, and the power quality of the microgrid is customized by the power margin of the multifunction grid connected inverter. The three phase and the three-phase two levels are used. Two kinds of multi-function grid connected inverters are carried out in detail, and the detailed simulation and experimental research are carried out. The feasibility and effectiveness of the multi-function grid connected inverter to provide the power quality control auxiliary service and to customize the power quality of the microgrid with the target are verified.
On the other hand, for the coordination control of power quality between multifunction grid connected inverters, two kinds of non interconnected line sharing control strategy for harmonic and reactive current of micro grid are proposed, based on the control and droop control of electrical conductivity, so as to organize and coordinate the multi function multifunction grid connected inverters which are relatively scattered in the microgrid. The independent autonomous region participates in the control of the power quality of microgrid. The strict experimental results verify that the two proposed control schemes are coordinated in the micro grid with multiple multi-function grid connected inverters, actively participating in the correctness and effectiveness of the power quality control of microgrid, and their adaptation to the micro grid "plug and play", "online hot plug" and so on. Ability to function.
2, in view of the independent autonomous operation of the grid connected inverters in microgrid, the "virtual synchronous generator" control technology of multi-function grid connected inverters is emphatically studied. The synchronization mechanism and swing equation, virtual inertia and damping of the traditional synchronous generator are simulated by the multi-function grid connected inverter, and the electromechanical transient transient over the 1Hz level swing equation is realized. At the same time, it can also simulate the voltage regulation and frequency modulation characteristics of the synchronous generator, provide the auxiliary service of voltage and frequency support to the power grid. The mathematical model of the control technology of the virtual synchronous generator is studied systematically, and the influence of the controller parameters on the performance of the virtual synchronous generator, as well as the virtual inertia and resistance are discussed. In addition, the optimized configuration method of the virtual synchronous generator energy storage unit is explained in detail. Through the study of the virtual synchronous generator control strategy, the multi-function grid connected inverter can have more flexibility and more friendly to the power grid. The model and the control side are verified by the simulation and experimental results. The validity and validity of the law.
3, in view of harmonic resonance and suppression of the micro grid with multiple grid connected inverters, the "output impedance reshaping" technique of multifunction grid connected inverters is emphatically studied. By remolding the output impedance of the multifunction grid connected inverter, the harmonic resonant frequency of a few kHz of the microgrid can be effectively damped. In the two angles of the ring equivalent circuit, the harmonic resonance mechanism of multiple grid connected inverters in the microgrid is explained in detail. On this basis, the concept of remolding the output impedance of a multi-function grid connected inverter is proposed. By controlling the output impedance of the multifunction grid connected inverter, more virtual resistance components are injected into the microgrid, thus effectively restraining the micro electricity. The simulation and experimental results verify the feasibility and effectiveness of the proposed output impedance reconstruction technology.
Aiming at the power quality control of the grid connected inverters in the microgrid and the three key technology requirements of the independent autonomous running harmonic resonance suppression, the "unified control of grid connected generation and power quality control" for harmonic load current, "virtual synchronous generator" technology for several Hz frequency bands and the "output" for several kHz bands, are introduced in this paper. The impedance remolding technology gives the corresponding countermeasures, which makes the grid connected inverters more flexible in performance, more diverse in function, and can provide more abundant auxiliary services to the microgrid. It has good research value and application prospects. Of course, with the development of technology, grid inverters (even other grid connected converter) It may also provide more abundant ancillary services for the power grid, which needs further study.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM464

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