多端口级联型固态变压器功率协同控制研究

发布时间：2018-06-04 19:21

  本文选题：多端口 + 级联型固态变压器　； 参考：《湖南大学》2016年硕士论文

【摘要】：随着国内外经济形势和能源形势的深刻变化,从传统化石能源向清洁新能源过渡的新一轮能源变革已经悄然展开。欧美等发达国家为了应对气候变化、促进经济发展、调整能源结构相继提出发展智能电网,我国也在政府工作报告中明确提出要“加强智能电网建设"。作为未来智能电网重要组成部分,固态变压器(Solid State Transformer, SST)是一种利用电力电子器件和变换技术实现电压等级转换和电力传输的新型智能化设备。与传统变压器相比,SST具有体积小、重量轻、环境友好以及故障隔离等特点,通过相关的控制技术可以对网侧电压电流和传输功率进行调控；同时提供了交直流端口,可有效整合分布式新能源、储能装置以及各种交直流负载,进而实现电网中功率潮流的协调分配,提高电网运行的效率和可靠性。受到当前电力电子器件水平的限制,固态变压器一般通过模块级联的方式来提升装置的容量和电压等级。级联的拓扑结构便于拓展、易封装,但存在模块之间的电压和功率均衡控制问题。本文以应用于配电网中级联型固态变压器为研究对象,对其应用控制方法进行了相关研究,提出一套基于“协同”思想的控制策略。首先,针对配电网中固态变压器采用模块级联形式所带来的模块间电压和功率均衡控制问题,通过分析输入级和中间级的开关等效电路,推导得出级联型固态变压器的内部功率传输模型,进而得出电压均衡和传输功率均衡的等价条件,在此基础上提出了一种简单、有效的前后级协同控制策略：输入级采用单相DQ坐标变换的共同占空比控制,中间级采用输入输出电压叠加控制,二者协同配合实现串联模块的均压和并联模块的均流控制。然后,针对分布式微源通过多端口固态变压器交直流端口接入配电网后,固态变压器对于微源、用户和电网之间的功率协调管理问题,提出一种基于固态变压器低压直流端口电压分区的功率协同控制策略。利用PSCAD/EMTDC软件平台建立了相应的仿真模型,并且在实验室搭建小功率试验样机,最后仿真和实验结果验证了本文所提多端口级联型固态变压器功率协同控制策略的有效性和可行性。
[Abstract]:With the profound changes of economic and energy situation at home and abroad, a new round of energy transformation from traditional fossil energy to clean new energy has been launched quietly. In order to cope with climate change and promote economic development, developed countries such as Europe and the United States have put forward the development of smart grid one after another by adjusting energy structure. In our government work report, we have clearly proposed to "strengthen the construction of smart grid". As an important part of the future smart grid, solid state transformer solid State Transformer, SST) is a new type of intelligent equipment which uses power electronic devices and conversion technology to realize voltage grade conversion and power transmission. Compared with the traditional transformer, SST has the characteristics of small size, light weight, friendly environment and fault isolation. It can regulate the voltage, current and transmission power of the grid side by means of the related control technology, and also provides the AC / DC port. It can effectively integrate distributed new energy, energy storage devices and all kinds of AC / DC loads, and then realize the coordinated distribution of power flow in the power grid, and improve the efficiency and reliability of power grid operation. Due to the limitation of the current power electronic devices, solid-state transformers usually use modular cascading to enhance the capacity and voltage level of the devices. The topology of cascade is easy to expand and encapsulate, but there are voltage and power equalization control problems between modules. In this paper, the application of solid state transformer in distribution network is studied, and a set of control strategy based on the idea of "cooperation" is put forward. Firstly, aiming at the problem of voltage and power equalization control between modules brought by solid-state transformer in distribution network, the switching equivalent circuit of input stage and intermediate stage is analyzed. The internal power transmission model of cascaded solid-state transformer is derived, and the equivalent condition of voltage equalization and transmission power equalization is obtained. The effective control strategy is as follows: the input stage adopts the common duty cycle control of single-phase DQ coordinate transformation, the middle stage adopts the input and output voltage superposition control, the two cooperate to realize the voltage sharing of the series module and the current sharing control of the parallel module. Then, after the distributed microsource is connected to the distribution network through the multi-port solid-state transformer, the power coordination management between the microsource, the user and the power grid is discussed. A power cooperative control strategy based on low voltage DC port voltage partition of solid state transformer is proposed. The corresponding simulation model is established by using PSCAD/EMTDC software platform, and a small power test prototype is built in the laboratory. Finally, the simulation and experimental results show the effectiveness and feasibility of the multi-port cascaded solid-state transformer power cooperative control strategy proposed in this paper.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM41
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本文编号：1978557