Dynamic Modeling and Design of Distributed Power Systems with Power Factor Correction

随着功率开关器件技术的进步，为各种工业和航空航天应用设计更小、更轻的电力电子系统的动力将继续增加。此外，随着非线性负载电源不断涌现在电力电子系统中，为了开发新的功率因数校正(PFC)技术以提高电能质量和效率，密集的研究和开发工作也将继续增加。这一努力将继续下去，特别是在政府监管变得越来越严格的情况下。拟议的研究的目标是解决分析中的一些关键问题和。具有功率因数校正的分布式电源系统(DPS)设计。这些问题的问题和挑战包括PFC变流器的拓扑结构、建模、DPS系统的稳定性等。在这个项目中，我们还将研究新的电流控制方法，用于稳定并联系统的输出并提供均匀的负载电流分配。本文所研究的变流器可用于离线应用，以改善功率因数校正。本项目将采用有源功率因数校正技术，在构建并联系统的同时，仍能达到接近单位功率因数。与传统方法不同，新开发的转换器系列将进一步消除线路电流失真，具有接近单位的功率因数。在项目为期两年的时间里，我们将开展以下主要工作：1)研究传统的建模方法及其在AC/DC功率因数校正变流器中应用的局限性；2)针对AC/DC功率因数校正变流器的单级拓扑结构，提出了新的建模方法；3)利用所开发的模型对选定的单个PFC变流器进行小信号、大信号分析和仿真，搭建硬件平台，并对所开发的模型进行实验验证，4)对各种并联方案的可靠性、暂态和共享性能以及模块间的相互作用进行了研究和比较；5)采用可行的并联方案集成多个前端PFC变流器和DC/DC负载变流器组成分布式电力系统；6)通过对同一分布式电力系统进行仿真，对各种简化的系统模型进行对比研究，对简化模型进行修改和精化，并对DPS分析和仿真进行硬件验证。以两个并联的交直流单开关功率因数连接变流器模块为例说明了所提出的控制思想。仿真结果表明，在系统稳定性和系统性能方面仍有改进的空间。

As power switching device technology advances, the drive for designing smaller-size and lighter-weight power electronic systems for various industrial and aerospace applications will continue to increase. Moreover, as nonlinear load power supplies continue to proliferate power electronic systems, intensive research and development efforts will also continue to grow in order to develop new Power Factor Correction (PFC) technology to improve power quality and efficiency. This effort will continue especially with government regulations become more and more stringent.The objective of the proposed research is to address some of the critical issues in the analysis and. design of distributed power supply systems (DPS) with power factor corrections. Problems and challenges of these issues include PFC converter topology, modeling, stability of DPS systems, etc. In this project, we will also investigate new current control methods used to stabilize the output and provide equal load current sharing in parallel connected systems. The converters that are investigated here can be used in off-line application to improve power factor correction. Active power factor correction technique will be used in this project to construct parallel-connected systems and still achieve near unity power factor. Unlike the traditional approach, the newly developed family of converters will result in further elimination of line current distortion, with near unity power factor. Finally, a working hardware unit will be constructed based on the conceptual designs of the power factor correction circuits used in distributed power systems.During the project's two-year period, we will carry out the following major tasks: 1) Investigate the conventional modeling techniques and their limitations for the applications in ac/dc power factor correction converters, 2) develop new modeling methodology for family of ac/dc power factor correction converters, focusing on single-stage single-switch topologies, 3) carry out small-signal, large-signal analysis and simulation on selected single PFC converters by using the developed models, set-up hardware platform and perform experimental verification for developed models, 4) investigate and compare various parallel schemes with respect to reliability, transient and sharing performance and interaction among modules, 5) integrate several front-end PFC converters and DC/DC load converters to form distributed power system using viable paralleling schemes, and finally, 6) conduct comparative study for various simplified system models by simulating the same distributed power system to modify and refine simplified model, and perform hardware verification for DPS analysis and simulation.The control concepts developed will be illustrated for a module of two-parallel connected ac-dc single switch power factor connection converters. The simulation results show that room for improvement is necessary when it comes to system stability and system performance.