孤岛模式下微网的性能优化控制策略研究

发布时间：2018-04-09 06:24

本文选题：微网　切入点：DSMS　出处：《北京交通大学》2014年博士论文

【摘要】：摘要：微网是由分布式电源、负荷、储能、监控和保护装置共同组成的小型发配电系统,它具有并网和孤岛两种运行模式,可提高负荷供电可靠性。微网中的分布式电源通常采用电力电子装置接入电网,电力电子装置惯性小且过载能力差,增加了微网系统的控制难度；而电力电子装置的灵活、可控特性则为微网系统电能质量改善提供了便利条件。基于电力电子装置的运行特性,本文对微网在孤岛模式下的稳定性提高和电能质量改善展开研究,主要工作如下： (1)围绕孤岛模式微网的小信号稳定性分析展开研究。基于李雅普诺夫第一法思想,对微网系统小信号模型计算及稳定性判定方法进行了描述。根据微源的控制特性,建立了单台下垂控制支撑微源(Droop-cntrol surpporting micro source, DSMS)状态方程,并对其小信号模型进行了计算。从多DSMS、供电微源(Feeding micro source, FMS)组网系统的拓扑结构出发,以特定系统为例,阐述了多DSMS、FMS组网系统的小信号模型计算方法。计算了负荷阻抗、下垂增益变化时特定多DSMS、FMS组网系统的特征值,确定了影响系统稳定性的关键参数,并采用时域仿真对关键参数计算结果的正确性进行了验证。 (2)围绕虚拟阻抗对DSMS控制性能的影响展开研究。从等效电路出发,分析不同线路阻抗对DSMS输出功率解耦控制性能的影响,确定了导致DSMS输出功率耦合的原因。给出基于虚拟阻抗实现DSMS功率解耦的控制方法,通过对DSMS实际输出功率的计算,阐述了虚拟阻抗实现DSMS输出功率解耦控制的机理,明确了不同功率耦合程度下虚拟阻抗选取的原则。根据虚拟阻抗的实现方法和线性化模型,分析了虚拟阻抗控制对DSMS输出电压和稳定性的影响。 (3)围绕多DSMS、FMS组网系统的电能质量改善策略展开研究。基于FMS系统的等效电路计算,确定了影响FMS系统谐振频率等效阻抗的关键参数,并对FMS系统的有源阻尼实现方法进行了讨论。从DSMS的谐波等效电路出发,推导了DSMS系统输出电压的谐波分量表示,提出了降低DSMS输出电压谐波分量的控制方法。对DSMS与公共耦合点(Point of common coupling, PCC)电压的基波负序矢量关系进行了分析,确定了导致PCC与DSMS的输出电压基波负序分量差异的原因,提出了基于二次控制降低PCC不平衡电压的控制策略,并分析了二次控制延时对系统稳定性的影响。 (4)围绕含多DSMS微网系统的负荷合理分担问题展开研究。给出了集中式负荷工况下的多DSMS微网系统等效电路,对线性不平衡负荷、非线性负荷工况下DSMS的负荷分担原理进行了分析,确定了线路阻抗对DSMS负荷分担性能的影响。对基于虚拟负序导纳实现负荷合理分担的控制原理进行了分析,提出了采用虚拟阻抗实现多DSMS系统负荷分担性能改善的控制策略。从DSMS基波负序、谐波分量等效电路出发,对DSMS输出电压的基波负序、谐波分量表达式进行了推导,分析了DSMS负荷分担性能改善控制策略对输出电压基波负序、谐波分量的影响。
[Abstract]:Abstract: microgrid is a distributed power supply, load, energy storage, small distribution power system monitoring and protection device composed of, it has two kinds of grid and island operation mode, can improve the reliability of power supplying. Distributed power in the microgrid usually uses power electronic devices connected to the power grid, power electronic devices and small inertia overload poor ability, increasing the difficulty of control system; and the power electronic equipment is flexible and controllable characteristics for micro grid power system provides the convenience of quality improvement. The operation characteristics of power electronic devices based on the microgrid in islanding mode improves the stability and power quality improvement research, the main work the following:
(1) research focus on the analysis of small signal stability of microgrid islanding mode. Lyapunov first method based on the idea of micro calculation and stability of small signal model network system determination method are described. According to the control characteristics of micro sources, a single microsource droop control support (Droop-cntrol surpporting micro source, DSMS) the equation of state, and the small signal model is calculated. From DSMS, the power supply of micro source (Feeding micro source, FMS) of the topological structure of the network system, in particular system as an example, describes DSMS, calculating the small signal model of FMS network system. The method of load impedance calculation, droop gain variation when the specific characteristics of DSMS, FMS network value, determine the key parameters affecting the stability of the system, and the correctness of the simulation calculation results of critical parameters are verified.
(2) the virtual impedance studies the impact of DSMS control performance. Starting from the equivalent circuit analysis, different line impedance of DSMS output power decoupling control performance influence, determine the causes of DSMS output power coupling. Given the control method of virtual impedance DSMS power decoupling based on DSMS, through the calculation of the actual output power the virtual impedance mechanism of DSMS output power decoupling control, the virtual impedance different power coupling under the principle of selection. According to the implementation method and the linear model of virtual impedance analysis, virtual impedance control effect on the output voltage of DSMS and stability.
(3) on DSMS, FMS network power quality improvement strategy is studied. Calculation of equivalent circuit based on the FMS system, to determine the effect of key parameters of FMS system resonant frequency equivalent impedance, and active damping of FMS system realization method are discussed. Starting from the DSMS harmonic equivalent circuit is derived the harmonic component of output voltage of the DSMS system, puts forward the method to control and reduce the DSMS output voltage harmonic component. To the point of common coupling (Point DSMS and of common coupling, PCC) fundamental negative sequence voltage vector relationship are analyzed, to determine the cause of the output voltage fundamental negative sequence differences between PCC and DSMS. Put forward two times lower PCC unbalanced control strategy based on voltage, and analyzed the influence of the two control delay on the stability of the system.
(4) the containing DSMS microgrid load sharing problem is studied. The DSMS centralized load microgrid equivalent circuit of linear unbalanced load, analyzed the load DSMS nonlinear load sharing principle, to determine the impact of performance sharing on DSMS load line impedance. The virtual negative sequence admittance control principle based on load sharing is analyzed, the control strategy was proposed to realize load sharing to improve the performance of multi DSMS system based on virtual impedance. From DSMS fundamental negative sequence and harmonic component equivalent circuit of the negative sequence component of the DSMS output voltage, harmonic component expressions are deduced and analyzed the DSMS load sharing control strategy to improve the performance of the output voltage fundamental negative influence, harmonic components.

【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM711

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