基于有限控制集的多电平变流器的模型预测控制

发布时间：2018-07-10 05:57

本文选题：有限控制集模型预测控制 + 欧拉离散法　；参考：《华东交通大学》2017年硕士论文

【摘要】：随着经济的迅速发展,环境污染和能源危机问题日益突出。新能源技术成为能源发展的重点,多电平变流器将产生的直流电转化为交流电是新能源发电并网的重要环节。传统的多电平变流器的控制策略采用双闭环PI控制,然而PI环节参数设计没有固定设置方法,调节不易。有限控制集模型预测控制(finite control set model predictive control,FCS-MPC)是一种强大的控制技术,具有高精度、灵活性、稳定性、易于实现和概念简单易懂等优点,所有控制要求可以由一个控制器同时考虑。本文对新能源发电并网中的多电平变流器采用有限控制集模型预测控制进行研究,主要研究如下:1)介绍了基于有限控制集的多电平变流器的模型预测控制的研究背景与意义。提出有限控制集模型预测控制,将其运用到变流技术中改善系统的稳态性能。2)详述了模型预测控制的理论。首先阐述了FCS-MPC的基本原理及其数学模型,其次介绍FCS-MPC的设计过程,包括三种系统模型离散化方法(前向欧拉法、后向欧拉法、中点欧拉法)、定义系统目标函数以及添加系统约束。3)介绍了三电平逆变器的拓扑结构及其工作原理,提出了对应的FCS-MPC控制算法。通过观察比较输出电流跟踪参考变量的效果,验证了有限控制集模型预测运用于三电平逆变器的可行性并通过比较了解了三种系统模型离散化方法的性能差异。4)介绍了模块化多电平换流器(modular multilevel converter,MMC)的工作原理,分析了MMC在三种坐标系(abc、αβ、dq)下的数学模型。描述了传统的双闭环PI控制和线性二次最优控制,推导了控制器的设计过程。并通过仿真比较两者的性能优劣。5)将模型预测控制运用于六电平MMC中。FCS-MPC定义的目标函数用于控制MMC输出电流、保持电容电压平衡和抑制环流。仿真结果表明FCS-MPC比传统的双闭环PI控制在跟踪MMC输出电流、保持电容电压平衡和抑制环流上的效果更优。
[Abstract]:With the rapid development of economy, environmental pollution and energy crisis are increasingly prominent. New energy technology has become the focus of energy development. The conversion of DC to AC generated by multilevel converters is an important link in the grid connection of new energy generation. The traditional control strategy of multilevel converter adopts double closed loop Pi control. However, there is no fixed setting method for Pi parameter design, so it is difficult to adjust. Finite control set model predictive control (finite control set model predictive control FCS-MPC) is a powerful control technology, which has the advantages of high precision, flexibility, stability, easy to implement and easy to understand. All control requirements can be considered by one controller at the same time. In this paper, the finite control set model predictive control for multilevel converters in grid-connected new energy generation is studied. The main research contents are as follows: 1) the research background and significance of model predictive control for multilevel converters based on finite control sets are introduced. A finite control set model predictive control is proposed and applied to variable current technology to improve the steady-state performance of the system (.2) the theory of model predictive control is described in detail. Firstly, the basic principle and mathematical model of FCS-MPC are introduced. Secondly, the design process of FCS-MPC is introduced, including three discretization methods of system model (forward Euler method, backward Euler method). Neutral point Euler method), defines the system objective function and adds system constraint .3) introduces the topology and working principle of the three-level inverter, and presents the corresponding FCS-MPC control algorithm. By observing and comparing the effects of output current tracking reference variables, The feasibility of applying finite control set model prediction to three-level inverter is verified, and the performance difference between the three discretization methods of system models is compared. (4) the principle of modularized multilevel converter (modular multilevel converter is introduced. The mathematical models of MMC in three coordinate systems (abc, 伪尾 -dq) are analyzed. The traditional double closed loop Pi control and linear quadratic optimal control are described, and the design process of the controller is deduced. The objective function defined by .FCS-MPC in six-level MMC is used to control the output current of MMC, keep the balance of capacitive voltage and restrain the circulation. The simulation results show that FCS-MPC is more effective than traditional double closed loop Pi control in tracking MMC output current, maintaining capacitance voltage balance and restraining circulation.
【学位授予单位】：华东交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46

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