模块级联型固态变压器及其控制策略的研究

发布时间：2018-03-16 01:05

本文选题：模块级联固态变压器　切入点：单相D-Q矢量控制　出处：《浙江大学》2014年硕士论文　论文类型：学位论文

【摘要】：固态变压器又称电力电子变压器,是一种通过电力电子变换技术实现电力系统中的电压变换和能量传递的新型变压器。它将电力电子的器件和变流技术与高频变压器相结合,实现传统电力变压器电压等级转换、隔离的功能。与常规变压器相比,固态变压器具有器件体积小、重量轻的特点；同时,通过先进的控制技术,它还可以实现对原边电流、副边电压以及功率的灵活控制,抑制来自用户侧的无功电流和谐波,降低电网电压跌落和频率变化对用户端的影响；并能提供低压直流母线和网络接口,可以提供直流供电,整合各种分布式电源,连接储能装置,实现电网中功率潮流的统一协调分配,提高整个电力系统的性能和可靠性。模块级联型固态变压器是通过采用对多个低压模块进行串并联组合的方式,来提高其电压和容量的等级,降低每个模块的电压电流应力,同时用多电平方法可以提高交流侧SPWM波的正弦度,有效减小了滤波器和整机的体积。但是各个模块的均压、均功率问题难以实现,电压和功率的不平衡使系统在电网电压波动和负载变化的情况下容易出现故障。本文分析了模块级联型固态变压器电路拓扑的工作原理,进行了建模并设计了电路参数,并搭建了实验平台。本文研究采用一种基于整流级共同占空比控制与DAB输入、输出电压跟随控制相结合的控制策略进行控制,并对这种控制方法进行了改进,不仅有效解决了固态变压器各模块之间均压、均功率问题,还提高了系统的响应速度。并最后通过理论分析、仿真与实验对两种控制方法进行了比较,验证了其可行性与可靠性。
[Abstract]:Solid-state transformer, also known as power electronic transformer, is a new type of transformer which realizes voltage conversion and energy transfer in power system through power electronic transformation technology. It combines power electronics devices and converter technology with high-frequency transformer. Compared with conventional transformers, solid-state transformers have the advantages of small size and light weight. At the same time, through advanced control technology, it can also realize the primary current, The flexible control of secondary voltage and power can restrain the reactive current and harmonic from the user side, reduce the influence of voltage drop and frequency change on the user side, and can provide low voltage DC bus and network interface, which can provide DC power supply. All kinds of distributed power sources are integrated, energy storage devices are connected to realize the unified and coordinated distribution of power flow in the power network, and the performance and reliability of the whole power system are improved. Modular cascade solid-state transformer is a series and parallel combination of several low-voltage modules to improve the voltage and capacity of the transformer and reduce the voltage and current stress of each module. At the same time, the sinusoidal degree of AC side SPWM wave can be improved by multilevel method, and the volume of filter and whole machine can be reduced effectively. However, the problem of equalizing voltage and average power of each module is difficult to realize. The imbalance of voltage and power makes the system prone to failure in the case of voltage fluctuation and load variation. In this paper, the working principle of the circuit topology of modular cascade solid-state transformer is analyzed, the circuit parameters are modeled, and the experimental platform is built. A common duty cycle control and DAB input based on the rectifier level are studied in this paper. The output voltage is controlled by the combined control strategy, and the control method is improved, which not only effectively solves the problem of voltage sharing and power sharing among the modules of solid-state transformer, but also improves the control method. Finally, through theoretical analysis, simulation and experiment, the two control methods are compared, and the feasibility and reliability of the two control methods are verified.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM41

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