固态变压器控制策略及在新能源领域中的应用研究

发布时间：2018-11-06 20:58

【摘要】：电能是一个国家国民经济的基本动力,太阳能、风能等蕴藏量极其丰富的新能源的开发利用,能保证廉价可靠的电能供应,帮助能源体系实现向低碳、高效、环保的转变。固态变压器(Solid State Transformer,简称SST)作为一种新型的电能变换设备,与传统的电力变压器相比,它融合了电力电子技术,采用高频隔离的中间环节,实现了原边副边的灵活控制。将SST应用于电力系统将提高系统的可控性,改善电能质量,且便于新能源发电并网,将推动未来智能电网的建设。本文主要针对SST的控制策略,以一种三级式SST作为研究对象,分别对三级式SST拓扑中的输入级、隔离级和输出级的数学模型和控制策略进行研究,并分析了该SST在新能源发电并网中的应用。本文的主要工作内容如下:1.介绍了一种含有中间直流环节的三级式SST拓扑,并对SST的核心环节三相电压源换流器进行了建模,建立了其在三相静止坐标系及两相同步旋转坐标系下的数学模型。本文对电压源换流器采用空间电压矢量脉冲宽度调制方法,对调制原理和实现过程进行了介绍。为实现将太阳能光伏发电输出低压直流并网至高压交流电网的目标,本文提出了一种输入串联输出并联的模块级联型逆变器拓扑结构并建立其数学模型。2.针对三级式SST各级的控制目标提出了相应的控制策略。输入级采用电压电流双闭环前馈解耦控制和模型预测控制;中间隔离级采用单移相控制;输出级采用电压电流双闭环控制和下垂控制;模块级联型逆变器采用载波移相控制。在Matlab/Simulink环境下,对所采用的控制策略进行仿真分析,仿真结果表明了所建数学模型及所用控制策略的正确性和有效性。3.基于SST的优良特性,对其在太阳能光伏和风力发电并网中的应用进行了研究,分析了 SST在新能源领域中的应用优势和应用价值。
[Abstract]:Electric energy is the basic power of a country's national economy. The development and utilization of new energy, such as solar energy, wind energy and so on, can guarantee the supply of cheap and reliable electric energy and help the energy system to realize the transition to low carbon, high efficiency and environmental protection. Solid-state transformer (Solid State Transformer,) is a new type of power conversion equipment. Compared with the traditional power transformer, it combines power electronics technology, adopts the intermediate link of high-frequency isolation, and realizes the flexible control of the primary side and secondary edge. The application of SST in power system will improve the controllability of the system, improve the power quality, facilitate the grid connection of new energy generation, and promote the construction of smart grid in the future. In this paper, aiming at the control strategy of SST, the mathematical model and control strategy of input stage, isolation stage and output stage in three-level SST topology are studied, taking a three-level SST as the research object. The application of the SST in the grid connection of new energy generation is analyzed. The main work of this paper is as follows: 1. A three-stage SST topology with intermediate DC link is introduced. The three-phase voltage source converter in the core link of SST is modeled and its mathematical model is established under the three-phase static coordinate system and two-phase synchronous rotating coordinate system. This paper introduces the principle and realization of voltage source converter using space voltage vector pulse width modulation method. In order to realize the goal of connecting low-voltage DC output of solar photovoltaic power to HVAC power grid, this paper presents a modular cascaded inverter topology with input series-output parallel connection and establishes its mathematical model. The corresponding control strategy is put forward for the control target of three-level SST. The input stage adopts voltage and current double closed loop feedforward decoupling control and model predictive control; the middle isolation stage adopts single phase shift control; the output stage adopts voltage and current double closed loop control and droop control; and the module cascade inverter adopts carrier phase shift control. The simulation results show that the mathematical model and the control strategy are correct and effective in Matlab/Simulink environment. Based on the excellent characteristics of SST, the application of SST in grid-connected solar photovoltaic and wind power generation is studied, and the advantages and application value of SST in the field of new energy are analyzed.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41

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