摘要
高频变压器的漏感作为电力电子变换器中的重要参数,对改善隔离型DC-DC变换器的运行模式和功率传输特性具有重要的意义。与圆导线相比,利兹线能够有效地减少高频磁性元件中的涡流损耗。然而,利兹线绕组的复杂结构给高频变压器漏感预测带来了严峻的挑战。一方面,磁心窗口各区域的磁场能量难以准确提取;另一方面,利兹线的多股和扭转结构难以准确表征。因此,该文基于镜像原理和网格化处理,精确提取磁心窗口不同区域的磁场能量。通过引入相对复数磁导率实现了多股利兹线的均匀化建模,揭示了宽频范围内磁场能量的衰减规律,提出坐标变换方法对利兹线的扭转结构进行表征,建立了计及利兹线扭转特征和频变特性的高频变压器漏感预测模型。最后,针对两种不同利兹线绕组的变压器模型,从计算精度和效率两方面进行了详细的实验研究和对比分析。结果表明,所提计算方法的最大偏差不超过4%,计算时间约为20 s,验证了该方法的准确性和高效性。
As an important parameter in power electronic converters,the leakage inductance of high-frequency transformers is of great significance in improving the operating mode and power transmission characteristics of isolated DC-DC converters.Compared with the solid round wire,the Litz wire can reduce eddy current losses in high-frequency magnetic components.However,the complicated structure of the Litz-wire windings poses a serious challenge to predicting leakage inductance in high-frequency transformers.On the one hand,it is difficult to precisely extract the magnetic field energy in various regions of the core window.On the other hand,it is hard to accurately characterize the multi-stranded and twisting structures of the Litz wires.Therefore,this paper presents a fast calculation method of leakage inductance in the high-frequency transformer with Litz-wire winding.Firstly,a homogenized equivalent process for Litz wire is proposed to enhance the flexibility of modeling and the efficiency of computation.The magnetic field energy variation with frequency inside the Litz-wire conductors are analyzed.Then,the 2-D magnetic field energy inside the core window is extracted based on the method of images to eliminate the impact of the edge effect.The internal and external magnetic fields at different locations in the winding are accurately characterized by introducing the meshing into the method of images,and a coordinate transformation method is proposed to consider the twisting structure of the Litz wires.Finally,two high-frequency transformer prototypes with different structures are designed and fabricated.Compared with the measurement results and two existing methods,the accuracy and efficiency of the proposed approach are verified.The following conclusions can be drawn.(1)A homogenized equivalent model of the Litz-wire twisting structure is developed by introducing the relative complex permeability,which simplifies the model building and reduces the computational cost.The variation of the magnetic field energy in the Litz wires with frequency is analyzed,and the magnetic field energy stored in the Litz wires gradually decreases with the frequency increase.(2)The meshing process is introduced into the method of images,and the coordinate transformation method is proposed to characterize the twisting structure of the Litz wire.It can counteract a part of the external magnetic field and reduce the magnetic field energy in the conductors.(3)Considering the twisting characteristics of the Litz wire and the high-frequency effect,a leakage inductance prediction model is developed based on the magnetic field energy variation with frequency.(4)The accuracy and efficiency of the proposed method are verified compared with the measurement and the current two analytical methods.The maximum error does not exceed 4%throughout the measurement frequency range,and the calculation time is about 20 seconds.Moreover,the proposed method can be effectively applied to fast iterative calculations in the optimal design of high-frequency transformers.
作者
陈天缘
赵志刚
郑宇萱
王凯
Chen Tianyuan;Zhao Zhigang;Zheng Yuxuan;Wang Kai(State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology,Tianjin 300401 China;Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province Hebei University of Technology,Tianjin 300401 China)
出处
《电工技术学报》
北大核心
2025年第8期2353-2364,共12页
Transactions of China Electrotechnical Society
基金
国家自然科学基金项目(52077053,52377008)
中央引导地方科技发展基金项目(226Z1601G)资助。
关键词
高频变压器
漏感
镜像法
利兹线绕组
频变特性
High-frequency transformer
leakage inductance
the method of images
Litz-wire windings
frequency-dependent characteristic
