|
|
An Accurate Thermal Resistance Network Model for Magnetic Elements Considering Thermal Anisotropy of Materials and Various Heat Transfer Ways |
Guo Xuan, Xiao Yunhao, Li Chi, Zheng Zedong |
State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing 100084 China |
|
|
Abstract The development trend of magnetic components is higher frequency, smaller volume, and higher power density. With the increase of power density, heat dissipation becomes a key factor affecting the reliable operation of magnetic components, which puts forward higher requirements for the thermal analysis of magnetic components. The traditional thermal analysis models have problems such as long calculation time and single heat transfer way. In addition, the thermal anisotropy, different distribution of loss density in magnetic core and interaction effect between temperature and loss are usually ignored. A precise and generalized analytical thermal modeling method is needed to meet the calculation requirements of the magnetic component optimization design and match the actual working condition with complex heat dissipation ways. The inductor made of an EE-type magnetic core is taken as an example, and the three-axis nine-thermal-resistance network model with thermal anisotropy is introduced for solving the heat conduction problem. A three-axis fifteen-thermal-resistance network model was proposed considering multiple heat transfer ways, thermoelectric coupling, material thermal anisotropy, and actual loss distribution of magnetic core. For multiple heat transfer ways, the influence of heat conduction, heat convection, and heat radiation should be considered because high-power density magnetic components are often used with water cooling, air cooling, or other cooling structures. Moreover, the influence of heat convection and heat radiation has been considered in the model as air thermal resistances. The magnetic field distribution influences the loss density distribution in each area. The loss distribution of the magnetic core is calculated by the 2D finite element simulation of the actual magnetic field to match the actual condition. The loss of winding and magnetic core requires iterative calculation because the temperature affects the magnetic core’s iron loss density and copper’s electrical conductivity. In contrast, the winding loss and magnetic core loss affect the temperature. In addition, the thermal anisotropy is considered in the model. The conduction thermal resistances of different axes in the Cartesian coordinate system are calculated by different thermal conductivities due to thermal anisotropy. At the frequency of 50 kHz, three working conditions of Vp=350 V, Vp=460 V, and Vp=590 V were selected to verify the model. The results show that the max relative error for calculating the magnetic core temperature is no more than 14%, and the max relative error in the highest temperature area of the magnetic core is no more than 6% under three working conditions. Compared with other thermal resistance network models, the precision of the thermal resistance network model can be improved by considering the material thermal anisotropy, thermoelectric coupling, and actual distribution of core loss. The single calculation time of the model can be reduced from several hours in 3D finite element simulation to almost one millisecond in the thermal resistance network. The total calculation time of the thermal resistance network model can meet the time requirement of calculating a large number of design points for optimizing a specific structure magnetic core. Based on the comprehensive thermal resistance network model, a general thermal modeling method is summarized for magnetic components composed of EE, EI, UU, and other typical magnetic cores. The thermal equivalent modeling of the air gap, edge effect, and leakage flux on flux density near the air gap can be considered in the model in the future. A more comprehensive analytical analysis of the temperature field can be carried out, and more precise temperature field calculation results can be obtained, providing a more reliable reference for the heat dissipation design of magnetic components.
|
Received: 18 January 2023
|
|
|
|
|
[1] 孙鹤, 李永建, 刘欢, 等. 非正弦激励下纳米晶铁心损耗的计算方法与实验验证[J]. 电工技术学报, 2022, 37(4): 827-836. Sun He, Li Yongjian, Liu Huan, et al.The calculation method of nanocrystalline core loss under non- sinusoidal excitation and experimental verification[J]. Transactions of China Electrotechnical Society, 2022, 37(4): 827-836. [2] Bahmani M A, Thiringer T, Rabiei A, et al.Com- parative study of a multi-MW high-power density DC transformer with an optimized high-frequency mag- netics in all-DC offshore wind farm[J]. IEEE Transactions on Power Delivery, 2016, 31(2): 857-866. [3] Villar I, Mir L, Etxeberria-Otadui I, et al.Optimal design and experimental validation of a medium- frequency 400kVA power transformer for railway traction applications[C]//2012 IEEE Energy Con- version Congress and Exposition, Raleigh, NC, USA, 2012: 684-690. [4] 王佳宁, 邹强, 胡嘉汶, 等. 一种中压绝缘大功率中频变压器的优化设计方法[J]. 电工技术学报, 2022, 37(12): 3048-3060. Wang Jianing, Zou Qiang, Hu Jiawen, et al.An optimal design method for medium-voltage insulated high-power medium-frequency transformer[J]. Transa- ctions of China Electrotechnical Society, 2022, 37(12): 3048-3060. [5] 李子欣, 高范强, 赵聪, 等. 电力电子变压器技术研究综述[J]. 中国电机工程学报, 2018, 38(5): 1274-1289. Li Zixin, Gao Fanqiang, Zhao Cong, et al.Research review of power electronic transformer techno- logies[J]. Proceedings of the CSEE, 2018, 38(5): 1274-1289. [6] Kolar J W, Bortis D, Neumayr D.The ideal switch is not enough[C]//2016 28th International Symposium on Power Semiconductor Devices and ICs, Prague, Czech Republic, 2016: 15-22. [7] 李伟力, 付敏, 周封, 等. 基于流体相似理论和三维有限元法计算大中型异步电动机的定子三维温度场[J]. 中国电机工程学报, 2000, 20(5): 15-18, 22. Li Weili, Fu Min, Zhou Feng, et al.Calculation of 3D stator temperature field of large and medium scale asynchronous motor on the basis of theory of fluid similarity and 3D FEM[J]. Proceedings of the CSEE, 2000, 20(5): 15-18, 22. [8] 李伟力, 周封, 侯云鹏, 等. 大型水轮发电机转子温度场的有限元计算及相关因素的分析[J]. 中国电机工程学报, 2002, 22(10): 85-90. Li Weili, Zhou Feng, Hou Yunpeng, et al.Calculation of rotor temperature field for hydro-generator as well as the analysis on relevant factors[J]. Proceedings of the CSEE, 2002, 22(10): 85-90. [9] 袁发庭, 吕凯, 刘健犇, 等. 基于电磁-热-结构多物理场耦合的铁心电抗器线圈结构优化方法[J]. 电工技术学报, 2022, 37(24): 6431-6441. Yuan Fating, Lü Kai, Liu Jianben, et al.Coil structures optimization method of iron core reactor based on electromagnetic-thermal-structure multi- physical field coupling[J]. Transactions of China Electrotechnical Society, 2022, 37(24): 6431-6441. [10] 李永建, 闫鑫笑, 张长庚, 等. 基于磁-热-流耦合模型的变压器损耗计算和热点预测[J]. 电工技术学报, 2020, 35(21): 4483-4491. Li Yongjian, Yan Xinxiao, Zhang Changgeng, et al.Numerical prediction of losses and local overheating in transformer windings based on magnetic-thermal- fluid model[J]. Transactions of China Electro- technical Society, 2020, 35(21): 4483-4491. [11] 谢颖, 胡圣明, 陈鹏, 等. 永磁同步电机匝间短路故障温度场分析[J]. 电工技术学报, 2022, 37(2): 322-331. Xie Ying, Hu Shengming, Chen Peng, et al.Thermal field analysis on inter-turn short circuit fault of permanent magnet synchronous motor[J]. Transa- ctions of China Electrotechnical Society, 2022, 37(2): 322-331. [12] 朱艺锋, 葛琼璇, 刘育红, 等. 75kVA三电平背靠背变流器的散热分析及优化[J]. 电工技术学报, 2012, 27(2): 103-108. Zhu Yifeng, Ge Qiongxuan, Liu Yuhong, et al.Analysis and optimization of cooling system for 75kVA three-level back-back converter[J]. Transa- ctions of China Electrotechnical Society, 2012, 27(2): 103-108. [13] 兰志勇, 魏雪环, 李虎如, 等. 基于集总参数热网络法的永磁同步电机温度场分析[J]. 电气工程学报, 2017, 12(1): 17-21, 32. Lan Zhiyong, Wei Xuehuan, Li Huru, et al.Thermal analysis of PMSM based on lumped parameter thermal network method[J]. Journal of Electrical Engineering, 2017, 12(1): 17-21, 32. [14] 张建忠, 姜永将. 基于等效热网络法的定频双转子永磁风力发电机的热分析[J]. 电工技术学报, 2015, 30(2): 87-97. Zhang Jianzhong, Jiang Yongjiang.Thermal analysis of constant frequency double rotor permanent magnet generator based on equivalent thermal network method[J]. Transactions of China Electrotechnical Society, 2015, 30(2): 87-97. [15] 王晓远, 高鹏. 等效热网络法和有限元法在轮毂电机温度场计算中的应用[J]. 电工技术学报, 2016, 31(16): 26-33. Wang Xiaoyuan, Gao Peng.Application of equivalent thermal network method and finite element method in temperature calculation of in-wheel motor[J]. Transa- ctions of China Electrotechnical Society, 2016, 31(16): 26-33. [16] 万萌, 应展烽, 张旭东, 等. 功率器件集总参数热路模型及其参数提取研究[J]. 电工技术学报, 2015, 30(21): 31-38. Wan Meng, Ying Zhanfeng, Zhang Xudong, et al.Research on the lumped parameter thermal circuit model and the parameter extraction method of power devices[J]. Transactions of China Electrotechnical Society, 2015, 30(21): 31-38. [17] Leibl M, Ortiz G, Kolar J W.Design and experimental analysis of a medium-frequency transformer for solid- state transformer applications[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2017, 5(1): 110-123. [18] Mogorovic M, Dujic D.Thermal modeling and experimental verification of an air cooled medium frequency transformer[C]//2017 19th European Con- ference on Power Electronics and Applications, Warsaw, Poland, 2017: 1-9. [19] Wrobel R, Mellor P H.A general cuboidal element for three-dimensional thermal modelling[J]. IEEE Transa- ctions on Magnetics, 2010, 46(8): 3197-3200. [20] Simpson N, Wrobel R, Mellor P H.Estimation of equivalent thermal parameters of impregnated electrical windings[J]. IEEE Transactions on Industry Applications, 2013, 49(6): 2505-2515. [21] 查俊伟, 王帆. 高导热聚酰亚胺电介质薄膜研究进展[J]. 物理学报, 2022, 71(23): 190-207. Zha Junwei, Wang Fan.Research progress of high thermal conductivity polyimide dielectric films[J]. Acta Physica Sinica, 2022, 71(23): 190-207. [22] Venkatachalam K, Sullivan C R, Abdallah T, et al.Accurate prediction of ferrite core loss with non- sinusoidal waveforms using only Steinmetz para- meters[C]//2002 IEEE Workshop on Computers in Power Electronics, Mayaguez, PR, USA, 2003: 36-41. [23] Tourkhani F, Viarouge P.Accurate analytical model of winding losses in round Litz wire windings[J]. IEEE Transactions on Magnetics, 2001, 37(1): 538-543. [24] Ferreira J A.Analytical computation of AC resistance of round and rectangular litz wire windings[J]. IEE Proceedings B (Electric Power Applications), 1992, 139(1): 21. [25] 谢文旺, 周尚礼, 吴昊文, 等. 基于不同材料温度系数差异的测温研究[J]. 自动化与仪器仪表, 2022(5): 49-52. Xie Wenwang, Zhou Shangli, Wu Haowen, et al.Research on temperature measurement based on the difference of temperature coefficients of different materials[J]. Automation & Instrumentation, 2022(5): 49-52. |
|
|
|