基于MMC中低压配电网STATCOM的研究

发布时间：2018-03-07 15:57

本文选题：模块化多电平变换器　切入点：静止同步补偿器　出处：《南京航空航天大学》2016年硕士论文　论文类型：学位论文

【摘要】：对配电网进行无功补偿是配电网安全运行的重要保障,无功补偿能够有效提高电网的经济效益,从而配电网提供用户以安全、高质量的电能。静止同步补偿器(STATCOM)是最新一代无功补偿装置,具有响应速度快、可连续调节、无功补偿效果卓越、输出谐波性能好、安装地点灵活方便、抑制电网电压波动等优点,成为无功补偿技术的研究热点。本文对基于模块化多电平变换器(MMC)的静止同步补偿器(STATCOM)进行了整体研究,包括:主电路参数的分析和设计、PWM调制技术、预充电阶段和稳态工作阶段的控制策略介绍、桥臂不对称时MMC-STATCOM的稳态特性分析与控制策略研究、系统软硬件设计、仿真和实验验证。本文分析了MMC变换器的运行原理,在只考虑桥臂电压和桥臂电流基波分量的前提下,推导了桥臂能量波动与电容容值之间的关系,提出了以抑制电容电压基频波动为目的直流侧电容设计方法;在综合考虑了MMC-STATCOM动态性能、桥臂电流纹波大小、输出功率能力等性能指标后,提出了限流电感感值的取值方法。为分析稳态情况下基于MMC变换器的STATCOM的工作特性,本文首先建立了MMC-STATCOM的系统数学模型,并设计了系统的电流型反馈解耦控制器,实现了无功功率和有功功率的独立控制。本文对比研究了合适MMC变换器的多电平脉冲调制技术,最近电平逼近调制(NLM)技术适合应用于子模块数较多的场合以及MMC的预充电阶段,载波移相正弦脉冲宽度调制(CPS-SPWM)技术由于其较好的输出特性更适合MMC稳态阶段。论文研究了MMC-STATCOM的直流电容电压控制策略,提出了基于CPS-SPWM调制技术的分级控制策略,实现了系统电容电压的平衡。在模块化多电平变换器上、下桥臂参数不对称时,基频交流分量在上、下桥臂之间不平均分配,同时桥臂电流中的直流分量和二倍频分量也会流入到交流侧。本文建立了桥臂参数不对称MMC-STATCOM的交流侧和直流侧模型,分析了不同频率下等效电路中桥臂不对称对稳态电流的影响,提出了抑制基频共模分量及二倍频共模分量并维持上、下桥臂直流电压稳态平衡的控制策略。仿真和实验结果验证了理论分析的正确性和控制策略的有效性。最后,论文完成了MMC-STATCOM实验样机的搭建,研究了装置的电路结构、工作原理、控制系统的软硬件设计。实验结果表明,MMC-STATCOM能实现容性和感性无功发生功能,系统稳态和动态性能良好,有效地验证了本文提出的控制策略的可行性和有效性。
[Abstract]:The reactive power compensation of distribution network is an important guarantee for the safe operation of the distribution network, reactive power compensation can effectively improve the economic benefit of power grid and distribution network, to provide users with safe, high quality of electric energy. Static synchronous compensator (STATCOM) is the latest generation of reactive power compensation device has fast response speed, continuous regulation of the reactive power compensation effect is remarkable, the output harmonic performance is good, the installation location is flexible and convenient advantages to suppress voltage fluctuation and so on, has become a research hotspot of reactive compensation technology. In this paper, based on the modular multilevel converter (MMC) of the static synchronous compensator (STATCOM) to the overall research, including: analysis and design the parameters of the main circuit, PWM modulation technology, pre charging control strategy stage and steady stage, the bridge arm asymmetry when the steady characteristics of MMC-STATCOM analysis and control strategy research, system hardware and software design, simulation and experiment Validation. This paper analyzes the operation principle of MMC converter, the only consideration of bridge arm voltage and bridge arm current fundamental component, is the bridge arm energy fluctuation and the capacitance between the values, put forward to the DC side capacitor design method to suppress the frequency fluctuation of capacitor voltage; considering dynamic the performance of MMC-STATCOM, the bridge arm current ripple, output power performance ability, and puts forward the method of value of current limiting inductance. The work characteristics of MMC converter based on STATCOM analysis under steady state, this paper established a mathematical model of MMC-STATCOM system, and the design of the current system of feedback decoupling controller. To realize the independent control of active power and reactive power. This paper studied multilevel pulse modulation technique suitable for MMC converter, the nearest level modulation (NLM) technology is suitable for The number of sub modules more occasions and MMC pre charging stage, carrier phase shifted sinusoidal pulse width modulation (CPS-SPWM) technology because of its good output characteristics is more suitable for MMC steady stage. The paper studies the DC capacitor voltage control strategy of MMC-STATCOM, put forward a hierarchical control strategy based on CPS-SPWM technology, realizes the system of capacitor voltage balance multi level converter. In the module, under the bridge arm asymmetry parameter, the fundamental frequency component in communication, between the lower bridge arm uneven distribution, and the DC component of the arm current and two harmonics will flow into the AC side. This paper establishes the AC side arm parameters of asymmetric MMC-STATCOM and DC the model, analyzes the impact of asymmetric equivalent circuit of bridge arm under different frequency of steady-state current, is proposed to suppress the fundamental frequency component and the two frequency common mode common mode component and maintain, under the bridge arm The control strategy of DC voltage balance. Simulation and experimental results verify the validity of the theoretical analysis and control strategy. Finally, the complete set of MMC-STATCOM prototype, the circuit structure, working principle of the device, hardware and software design of the control system. The experimental results show that MMC-STATCOM can realize the compatibility and inductive reactive functional system, good steady-state and dynamic performance, effectively verify the feasibility of the proposed control strategy and effectiveness.

【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM761

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