电力电子变压器中高频变压器磁芯和绕组特性的研究

发布时间：2018-11-02 15:47

【摘要】：电力电子变压器(Power Electronic Transformer，简称PET)是一种新型变压器，它通过电力电子器件和电力电子变换技术，对能量进行转换与控制，能降低传统变压器的体积和重量，实现节材和节能目的。高频变压器是PET的核心器件，起隔离和传输功率的作用，其性能好坏直接决定PET的性能好坏。性能差的变压器损耗大，效率低，影响系统电路的稳定性和可靠性，甚至引起电力电子器件的故障，导致能量转换失败。本文明确了高频变压器的研究难点，分析了它的等效电路，进行了高频磁性材料特性实验。设计了不同绕组结构的10kVA高频变压器，并对其进行了相关电磁参数、空载特性、短路特性的测量和研究。制作了用于20kHz、10kVA光伏逆变系统的高频变压器。首先，对高频变压器的等效电路和参数计算进行了分析，根据电磁感应定律设计了高频磁性材料特性测试的实验平台，分析了测量结果，得出了铁氧体、非晶合金和纳米晶合金三种磁性材料正弦激励下的高频特性，绘制了它们的磁化曲线和磁滞回线，，并对磁性材料不同频率下的损耗进行了计算，为设计和制作高频变压器提供了具有参考价值的材料特性数据。其次，分析了磁性材料损耗的传统模型，在高频磁性材料特性测试得到数据的基础上，得到了纳米晶磁芯的高频磁芯损耗模型，即高频矫顽力、高频磁芯损耗和最大磁通密度、频率的关系。基于三维拟合提出了依据斯坦梅兹(Steinmetz)系数判定高频磁芯损耗的方法，为高频变压器磁芯材料的选型提供有力的参考依据。最后，用有限元方法分析计算了高频变压器绕组在不同条件下的高频效应，以及不同绕组结构对高频变压器电磁参数的影响。设计并完成了两种绕组结构(三明治式、交叉换位式)的高频变压器样机，通过对它们电磁参数的测定及特性分析，明确了交叉换位式绕制技术可减少高频变压器损耗的优势。基于以上实验研究，研制出用于20kHz、10kVA光伏逆变系统的高频变压器，该高频变压器采用了改进的交叉换位式结构，其效率最高可达99.3%。
[Abstract]:Power electronic transformer (Power Electronic Transformer,) is a new type of transformer. It can reduce the volume and weight of traditional transformer by means of power electronic device and power electronic transformation technology to convert and control the energy. The purpose of saving materials and saving energy is realized. High frequency transformer is the core device of PET. It plays the role of isolating and transmitting power. Its performance directly determines the performance of PET. The transformer with poor performance has a large loss and low efficiency, which affects the stability and reliability of the system circuit, and even causes the failure of the power electronic device, which leads to the failure of the energy conversion. In this paper, the research difficulties of high frequency transformer are defined, its equivalent circuit is analyzed, and the characteristic experiment of high frequency magnetic material is carried out. The 10kVA high-frequency transformer with different windings is designed, and its electromagnetic parameters, no-load characteristics and short-circuit characteristics are measured and studied. A high frequency transformer for 20 kHz 10 kVA photovoltaic inverter system has been fabricated. First of all, the equivalent circuit and parameter calculation of high frequency transformer are analyzed. According to the law of electromagnetic induction, the experimental platform for testing the characteristics of high frequency magnetic material is designed, and the measurement results are analyzed, and the ferrite is obtained. The high frequency characteristics of amorphous alloy and nanocrystalline alloy under sinusoidal excitation are studied. Their magnetization curves and hysteresis loops are drawn, and the loss of magnetic material at different frequencies is calculated. The material characteristic data with reference value are provided for the design and manufacture of high frequency transformer. Secondly, the traditional loss model of magnetic material is analyzed. On the basis of the data obtained from the characteristic test of high frequency magnetic material, the high frequency core loss model of nanocrystalline magnetic core is obtained, that is, high frequency coercivity, high frequency core loss and maximum flux density. The relation of frequency. Based on 3D fitting, a method of determining high frequency core loss based on Steinmez (Steinmetz) coefficient is proposed, which provides a powerful reference basis for the selection of core materials for high frequency transformers. Finally, the high frequency effect of high frequency transformer windings under different conditions and the influence of different winding structures on the electromagnetic parameters of high frequency transformer are analyzed and calculated by finite element method. A prototype of two kinds of windings (sandwich type, cross transposition type) is designed and completed. By measuring their electromagnetic parameters and analyzing their characteristics, the advantages of cross-transposition winding technology to reduce the loss of high frequency transformer are determined. Based on the above experimental research, a high-frequency transformer for 20kHz 10kVA photovoltaic inverter system is developed. The high frequency transformer adopts an improved cross-transposition structure, and its efficiency can reach 99.3%.
【学位授予单位】：河北工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM433

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