用于电力电子变压器的双向全桥DC-DC变换器研究

发布时间：2018-07-04 11:17

本文选题：电力电子变压器 + 双向全桥DC-DC变换器　；参考：《北京交通大学》2016年硕士论文

【摘要】：电力电子变压器(Power Electronic Transformer, PET)是将现代电力电子技术和变压器技术以及电能变换技术相结合而产生的一种智能化电力设备。PET除了具备传统电力变压器的功能外,还可以实现对输入电流和输出电压的灵活控制,具有功率密度高、交直流接口多样、可控性好等特点,被广泛应用于智能电网、轨道牵引等场合。电力电子变压器中的一个重要环节为DC-DC变换环节,该环节的作用是实现电气隔离以及能量传输等功能。本文以隔离型双向全桥DC-DC变换器为研究对象,运用理论分析、仿真和实验验证等手段,对电力电子变压器中的DC-DC变换环节进行了研究。PET中的DC-DC变换环节是影响其装置体积重量和功率传输损耗的关键部分。本文首先对DC-DC变换器工作原理和工作特性进行了分析,分别对单移相控制方式、单侧和双侧双重移相控制方式下变换器的回流功率和电流应力进行了建模分析,研究了几种控制方式下回流功率及电流应力的规律,并进行了仿真验证。为了进一步提高变换器传输功率的效率、减少传输功率过程中的损耗,本文进行了最小回流功率和最小电流应力控制策略的研究。在相应传输功率、回流功率和电流应力建模的基础上,推导出最小回流功率和最小电流应力实现的条件。针对回流功率,研究了单侧双重移相控制方式下基于单闭环的最小回流功率控制策略和基于软开关技术的最小回流功率控制策略；针对电流应力,研究了三种控制方式下的最小电流应力控制策略,并将三种控制方式下的电流应力规律加以对比分析。最后通过仿真对控制策略进行了验证。针对级联型PET中间DC-DC变换环节中各级单元间多个DC-DC变换器的均流问题,本文研究了三种并联均流的控制策略,给出了各种控制策略的方案,分析了各种控制策略的优缺点,并对三种控制策略进行了仿真,仿真结果验证了控制策略的有效性。本文在理论分析的基础上,设计并研制了一个3kW实验平台,并对基于单闭环最小回流功率控制方法、基于软开关技术的最小回流功率控制方法和三种控制方式下变换器的最小电流应力控制方法以及多模块并联时的基于采输出电流的均流控制方法进行了实验验证。实验结果验证了理论分析和仿真分析的正确性以及控制策略的有效性。
[Abstract]:Power Electronic Transformer (PET) is a kind of intelligent power equipment, which combines modern power electronics technology with transformer technology and power conversion technology. In addition to the functions of traditional power transformers, PET is a kind of intelligent power equipment. It can also realize the flexible control of input current and output voltage, with high power density, diverse AC / DC interface and good controllability. It has been widely used in smart grid, track traction and other occasions. DC-DC transform is an important link in power electronic transformer. The function of this link is to realize electrical isolation and energy transmission. In this paper, the isolated bi-directional full-bridge DC-DC converter is studied by means of theoretical analysis, simulation and experimental verification. The DC-DC conversion link in power electronic transformer is studied. The DC-DC conversion link in PET is the key part that affects the device volume weight and power transmission loss. In this paper, the working principle and working characteristics of DC-DC converter are analyzed, and the reflux power and current stress of DC-DC converter under single phase shift control mode, single side and double side phase shift control mode are modeled and analyzed respectively. The law of reflux power and current stress under several control modes is studied and verified by simulation. In order to further improve the efficiency of the converter transmission power and reduce the loss in the transmission power process, the minimum reflux power and the minimum current stress control strategy are studied in this paper. Based on the modeling of the corresponding transmission power, reflux power and current stress, the conditions for the realization of the minimum reflux power and the minimum current stress are derived. Aiming at the reflux power, the minimum reflux power control strategy based on single closed loop and the minimum backflow power control strategy based on soft switch technology are studied under the single-side and double-phase shift control mode. The minimum current stress control strategy under three control modes is studied, and the current stress law under the three control modes is compared and analyzed. Finally, the control strategy is verified by simulation. In order to solve the current sharing problem of multiple DC-DC converters between various units in cascade PET intermediate DC-DC converter, three parallel current-sharing control strategies are studied in this paper, and various control strategies are presented, and the advantages and disadvantages of each control strategy are analyzed. Three control strategies are simulated, and the simulation results verify the effectiveness of the control strategy. On the basis of theoretical analysis, a 3kW experimental platform is designed and developed in this paper. The minimum reflux power control method based on soft switching technology, the minimum current stress control method of converter under three control modes and the current sharing control method based on output current of multi-module parallel connection are verified by experiments. The experimental results verify the correctness of the theoretical analysis and simulation analysis and the effectiveness of the control strategy.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM46

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