智能微型电网系统孤岛模式中逆变器并联控制技术的研究

发布时间：2018-01-18 00:01

本文关键词：智能微型电网系统孤岛模式中逆变器并联控制技术的研究　出处：《浙江大学》2014年博士论文　论文类型：学位论文

【摘要】：在微型电网孤岛模式中,采用多台电压源型逆变器并联可以使微型电网具有更好的冗余性、稳定性和可靠性,但是各台逆变器输出电压之间的微小差异会在并联系统中产生环流,引发逆变器输出的有功功率和无功功率不平衡,严重时会导致逆变器过载甚至并联系统的崩溃。因此,如何根据微型电网中每一个逆变器单元的功率容量,精确的实现按任意比例均分用户负载功率,并且有效的抑制系统内部的环流,避免任何一个单元因为过载或者过流受到损害,对于智能微型电网的能量管理系统的设计来说是一个很大的挑战。有鉴于此,本文将工作重点放在微型电网孤岛模式中逆变器并联系统控制技术的研究,通过对多台电压源型逆变器并联系统的数学建模分析,设计一套行之有效的控制系统,以实现智能微型电网能量管理系统在孤岛模式中的设计需求。首先,本文简要介绍了智能微型电网的定义,拓扑结构,运行模式和控制系统,并对电力电子技术在智能微型电网中的应用以及智能微型电网中逆变器的工作模式进行了探讨。在此基础之上,本文对传统的逆变器并联控制技术进行了分析和总结,提出了结合有线并联和无线并联二者优势的改进方向。其次,本文对多台电压源型逆变器并联系统进行数学建模分析,提出了多台电压源型逆变器按照任意比例分担负载功率情况下逆变器并联系统的统一数学模型。随后通过对并联系统中连线阻抗的优化设计,本文提出了优化的多台电压源型逆变器并联系统的数学模型,包括优化并联系统的稳态模型,优化并联系统的环流数学模型,优化并联系统的环流小信号模型。同时,本文还对优化的逆变器并联系统的动态特性进行了研究。第三,在优化的逆变器并联系统数学模型基础上,本文从以下几方面对逆变器连线阻抗进行了分析,包括：(1)逆变器连线阻抗对并联系统环流的影响；(2)逆变器连线阻抗对交流母线电能质量的影响；(3)逆变器连线阻抗对并联系统功率损耗的影响。随后,本文基于以上分析,对优化的并联系统中逆变器连线阻抗参数的设计原则进行了总结。第四,在优化的逆变器并联系统数学模型基础上,本文提出了逆变器并联系统的环流功率数学模型,描述了在多台电压源逆变器并联系统中按照任意比例均分负载功率时环流功率与各台逆变器输出电压幅值差和相位差的数学函数关系。在环流功率数学模型的基础上,本文对传统下垂法抑制环流的机制建立了数学模型,并对传统下垂法的优点和缺点进行了总结。随后针对传统下垂法的缺点,本文提出了一种基于环流功率的并联控制策略(ω-Pcir和V-Qcir控制),并对其进行数学建模分析,从理论上验证了改进并联控制策略的优势。第五,本文结合有线并联的优势,以及智能微型电网的应用背景,尤其是根据并网／孤岛模式切换过程的设计需求,对改进的并联控制策略进行修正,提出了一种应用于智能微型电网孤岛模式的包括稳态电压控制器和并网前再同步控制器在内的控制策略。第六,根据本文的理论研究成果和设计的控制策略,对微型电网孤岛模式中逆变器控制系统的实现方案进行了细化分析,随后对微型电网中逆变器单元的离散控制系统和功率电路涉及的参数进行分析和设计。在此设计过程中,本文针对传统功率算法的优缺点进行了分析,提出了一种基于p-1瞬时功率理论的改进功率算法。最后,本文通过仿真和实验对本文提出的研究成果进行了验证：(1)通过PLECS仿真平台对优化的多台电压源型逆变器并联系统数学模型,环流功率数学模型,改进的并联控制策略以及微型电网孤岛模式控制系统进行仿真验证；(2)搭建了三台单相逆变器样机,组建逆变器并联系统,用于模拟微型电网的孤岛运行模式,对本文设计的控制系统进行实验验证。根据PLECS软件仿真结果,验证了本文提出的电压源逆变器并联系统的优化数学模型和环流功率数学模型的正确性以及可行性。同时根据仿真和实验结果证明,本文提出的基于环流功率数学模型的改进并联控制策略(即ω-Pcir和V-Qcir控制),能够有效地抑制并联系统中的有功环流和无功环流,相比于传统下垂法控制策略有更佳的稳态性能和良好的动态性能,是一种非常适合应用于智能微型电网孤岛模式中多台电压源型逆变器并联系统的控制策略。
[Abstract]:In the micro grid islanding mode, the redundancy of the parallel connection of a plurality of voltage source inverter can make the micro grid has better stability and reliability, but little difference between the output voltage of each inverter produces circulation in parallel system, causing the inverter output active power and reactive power imbalance will lead to serious inverter parallel system overload or even collapse. Therefore, according to the micro grid in each inverter unit power capacity, the realization of sharing user load power at any ratio, and effectively suppress the internal circulation, avoid any one unit because of overload or over-current damage, for the design of intelligent micro energy management system the grid is a big challenge. In view of this, this paper will focus on the micro grid islanding mode in parallel inverter Research on system control technology, through the mathematical modeling of multiple voltage source inverter parallel system analysis, design a set of effective control system to achieve the design requirements in islanding mode in smart micro grid energy management system. Firstly, this paper briefly introduces the definition of smart micro grid topology, operation mode and control system, and the electric power electronic technology in the smart micro grid and the application of intelligent inverter microgrid operation mode are discussed. On this basis, the parallel inverter of the traditional control technology are analyzed and summarized, put forward the improvement direction of the combination of wired and wireless parallel parallel two advantage. Secondly, this paper the voltage source type inverter parallel system of multiple mathematical modeling analysis, put forward a voltage source inverter with arbitrary load power sharing ratio The unified mathematical model of parallel inverter system conditions. Then based on the optimal design of parallel system of line impedance, this paper presents the mathematical model of multiple voltage source inverter parallel system optimization, including the steady-state optimization model of parallel system, circulation optimization mathematical model of parallel system, circulation of small signal model of parallel system optimization. At the same time, the dynamic characteristics optimization of parallel inverter system is studied. Third, based on the mathematical model of parallel inverter system optimization, this paper from the following aspects of inverter connected line impedance is analyzed, including: (1) effect of line impedance of parallel inverter system circulation; (2) effects of inverter line impedance on the AC bus power quality; (3) effect of line impedance of inverter parallel system power loss. Then, based on the analysis based on the optimization The design principle of inverter line impedance parameters in parallel system are summarized. Fourth, based on the mathematical model of parallel inverter system optimization, proposed power circulation mathematical model of parallel inverter system, describes the voltage source inverter and parallel system in Taiwan were according to any proportion circulation power and the inverter output voltage when the load power amplitude difference and phase difference function. Based on the mathematical model of power circulation, circulation mechanism of inhibition of the traditional droop method to establish a mathematical model, and the advantages and disadvantages of traditional droop method are summarized. Then according to the shortcomings of traditional droop method, this paper presents a parallel circulation power control strategy based on (Omega -Pcir and V-Qcir control), and carries on the mathematical modeling analysis, the improved parallel control strategy advantage in theory Fifth. In this paper, the advantages of parallel cable, and the application background of smart micro grid, especially according to the design requirements of grid connected / island mode switching process, the improved parallel control strategy is modified, the paper presents a design of intelligent micro grid islanding mode including steady-state voltage controller and synchronous controller, grid connected before control strategy. Sixth, based on the theoretical research results and the design of control strategy, implementation scheme for the inverter control system of microgrid islanding mode is analyzed in detailed analysis, analysis and design parameters then discrete control system and power circuit of inverter type micro grid unit involved. In the design process, in this paper. The disadvantages of the traditional power of the algorithm is analyzed, and proposes an improved algorithm P-1 power based on instantaneous power theory. Finally, this paper The results of simulation and experiment in this paper was verified: (1) through the PLECS simulation platform of multiple voltage source inverter mathematical model of parallel system optimization, power circulation mathematical model, parallel control strategy and control system of microgrid islanding mode simulation improved; (2) built three single-phase the formation of inverter prototype, parallel inverter system for islanding operation mode of micro grid simulation and control system designed in this paper is verified by experiment. According to the simulation results of PLECS software, confirmed the optimized mathematical model and mathematical model of circulation power voltage source inverter system proposed by this paper is correct and feasible. At the same time, according to the results of simulation and experiment proved that the improved parallel circulation power mathematical model control strategy based on the proposed (i.e. Omega -Pcir and V-Qcir, can effectively control) Suppression of active parallel circulation system and reactive power circulation, compared to the traditional droop method has better control of steady-state performance and good dynamic performance, is a very suitable for the intelligent microgrid islanded multiple voltage source inverter parallel system control strategy.

【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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