|
|
|
| Optimization Design of Insulation Structure of Medium Voltage and High Frequency Transformer Based on Bayesian Optimization and CRITIC Method |
| Zhao Zhigang1,2, Liu Yongjun1,2, Chen Tianyuan1,2, Zhang Shi1,2, Zhang Zijie1,2 |
1. State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin 300401 China;
2. Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province Hebei University of Technology Tianjin 300401 China |
|
|
|
Abstract High-frequency transformer (HFT) plays an important role in power conversion devices such as power electronic converters, facilitating voltage conversion and isolation. The corresponding optimized design is a crucial aspect in achieving high power density, high efficiency, and high reliability. HFT is characterized by compact size, high power density, and constrained insulation design margins, faces significant insulation challenges. This paper proposes an insulation structure and corresponding insulation design methodologies for medium-voltage, high-frequency transformer used in isolated DC-DC converters.
A sandwich-type transformer structure is designed that employs an insulation package incorporating an internal air gap. By inserting an air gap between the insulating bobbin and the epoxy potting resin, the peak electric-field strength is reduced while heat dissipation is improved. This structure transfers the region of maximum field into the bulk insulating material, thereby protecting the windings and magnetic cores and mitigating the effects of partial discharge. And it was verified using finite element simulation.
A detailed analysis is presented of the fundamentals of the method of the mirror charge for solving two-dimensional electrostatic field problems. The maximum electric field strength in the high-frequency transformer’s 2-D domain is extracted using both the finite-element method and the mirror charge method, the discrepancy between the two is within 3%, while the mirror charge delivers roughly a tenfold speedup. Based on this, the mirror charge is employed to compute and constrain the insulation clearances of transformer components embedded in a single dielectric medium.
A multi-objective optimization model is constructed using the CRITIC method, which determines the information entropy weight coefficients by calculating the comparative intensity and conflict analysis of the maximum electric field strength and insulator volume dual indicators. Based on this, the Bayesian optimization method is introduced to achieve the collaborative optimization of reducing transformer electric field strength and volume reduction within the constraints of evaluation times by constructing a Gaussian process surrogate model and an improved expected improvement acquisition function. Simulation results show that, compared to conventional optimization schemes, the proposed design reduces the maximum field strength by approximately 18%, and reduces the volume by about 10% compared to conservative schemes.
Insulation tests were conducted to verify the insulation performance and reliability of the transformer prototype, including an impulse voltage test at 10 kV, a short-time withstand voltage test at 8 kV, and a partial discharge test at 7.2 kV. All the results met the relevant requirements.
|
|
Received: 07 April 2025
|
|
|
|
|
|
[1] 周月宾, 魏丞崧, 朱小全, 等. 基于多绕组变压器的模块化输入独立输出串联光伏直流汇集变换器[J]. 电工技术学报, 2025, 40(15): 4874-4888.
Zhou Yuebin, Wei Chengsong, Zhu Xiaoquan, et al.Modular input independent output series photovoltaic DC collection converter based on multi-winding transformer[J]. Transactions of China Electrotechnical Society, 2025, 40(15): 4874-4888.
[2] 吉兴全, 张丽泓, 刘琪, 等. 电压与容量约束下柔性互联配电网安全裕度评估与优化提升[J]. 电力系统自动化, 2025, 49(13): 52-60.
Ji Xingquan, Zhang Lihong, Liu Qi, et al.Evaluation and optimization improvement for safety margin in flexibly interconnected distribution network under voltage and capacity constraints[J]. Automation of Electric Power Systems, 2025, 49(13): 52-60.
[3] 程鹤, 徐恺, 李朋圣, 等. 三相CLLC谐振变换器磁集成平面变压器设计与优化[J]. 电工技术学报, 2024, 39(12): 3774-3786.
Cheng He, Xu Kai, Li Pengsheng, et al.Design and optimization of three-phase CLLC resonant converter with magnetic integrated planar transformer[J]. Transactions of China Electrotechnical Society, 2024, 39(12): 3774-3786.
[4] Yi Zheyuan, Sun Kai, Liu Hanyu, et al.Design and optimization of the insulation of medium-voltage medium-frequency transformers for solid-state transformers[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2022, 10(4): 3561-3570.
[5] Guo Zhicheng, Yu Ruiyang, Xu Wei, et al.Design and optimization of a 200 kW medium-frequency transformer for medium-voltage SiC PV inverters[J]. IEEE Transactions on Power Electronics, 2021, 36(9): 10548-10560.
[6] Wang Weiwang, Liu Ying, He Jiefeng, et al.An improved design procedure for a 10 kHz, 10 kW medium-frequency transformer considering insulation breakdown strength and structure optimization[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2022, 10(4): 3525-3540.
[7] 陈彬, 曹红霞, 王帅兵, 等. 基于响应面法的多绕组中频变压器绝缘结构优化设计[J]. 绝缘材料, 2023, 56(4): 68-76.
Chen Bin, Cao Hongxia, Wang Shuaibing, et al.Optimization design of insulation structure of multi-winding medium frequency transformer based on response surface method[J]. Insulating Materials, 2023, 56(4): 68-76.
[8] 刘刚, 高成龙, 胡万君, 等. 基于改进的连续局部枚举采样和径向基函数响应面法的变压器静电环结构优化设计[J]. 电工技术学报, 2023, 38(23): 6266-6278.
Liu Gang, Gao Chenglong, Hu Wanjun, et al.Optimized design of transformer electrostatic ring based on radial basis function response surface method with enhanced successful local enumeration sampling[J]. Transactions of China Electrotechnical Society, 2023, 38(23): 6266-6278.
[9] 刘丰硕, 汲胜昌, 党永亮, 等. 基于C-MOEA/D约束多目标优化算法的中频变压器绝缘结构全局优化设计方法[J]. 高电压技术, 2025, 51(2): 956-966.
Liu Fengshuo, Ji Shengchang, Dang Yongliang, et al.Global optimal design method for insulation structure of medium frequency transformer based on constrained multiobjective optimization algorithm C-MOEA/D[J]. High Voltage Engineering, 2025, 51(2): 956-966.
[10] Yi Zheyuan, Sun Kai, Lu Shilei, et al.High-precision simulation for structure and efficiency optimization of high-power high-frequency transformer[C]//2020 IEEE Energy Conversion Congress and Exposition (ECCE), Detroit, MI, USA, 2020: 3524-3531.
[11] Jaritz M, Blume S, Biela J.Design procedure of a 14.4 kV, 100 kHz transformer with a high isolation voltage (115 kV)[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2017, 24(4): 2094-2104.
[12] Zhao Shishuo, Li Qiang, Lee F C, et al.High-frequency transformer design for modular power conversion from medium-voltage AC to 400 VDC[J]. IEEE Transactions on Power Electronics, 2018, 33(9): 7545-7557.
[13] Li Zheqing, Hsieh E, Li Qiang, et al.High-frequency transformer design with medium-voltage insulation for resonant converter in solid-state transformer[J]. IEEE Transactions on Power Electronics, 2023, 38(8): 9917-9932.
[14] Guo Zhicheng, Sen S, Rajendran S, et al.Design of a 200 kW medium-frequency transformer (MFT) with high insulation capability[C]//2020 IEEE Energy Conversion Congress and Exposition (ECCE), Detroit, MI, USA, 2020: 3471-3477.
[15] Adhikari B, Ghassemi M.A review of electrical insulation challenges in medium voltage high-frequency transformers for solid state transfor- mers[C]//2025 IEEE Kansas Power and Energy Conference (KPEC), Manhattan, KS, USA, 2025: 1-5.
[16] Zhao Yikun, Zhang Guoqiang, Guo Runrui, et al.The breakdown characteristics of thermostable insulation materials under high-frequency square waveform[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2019, 26(4): 1073-1080.
[17] Wang Zhaoxin, da Silva F F, Sørensen H, et al. The interactions analysis for high frequency transformers insulation under multi-stress of high voltage, high frequency, and high temperature[C]//2023 IEEE 2nd International Power Electronics and Application Symposium (PEAS), Guangzhou, China, 2023: 734-738.
[18] 王威望, 罗宇靖, 关子凌, 等. 高功率密度中高频变压器绝缘与散热研究进展与展望[J]. 高电压技术, 2024, 50(10): 4388-4406.
Wang Weiwang, Luo Yujing, Guan Ziling, et al.Research progress and technical prospect in insulation and heat dissipation of high power density medium-high frequency transformer[J]. High Voltage Engineering, 2024, 50(10): 4388-4406.
[19] 王威望, 李睿喆, 何杰峰, 等. 快速陡脉冲重复电场下高频变压器绝缘介质损耗与冲击能量积聚特性[J]. 电工技术学报, 2023, 38(5): 1206-1216.
Wang Weiwang, Li Ruizhe, He Jiefeng, et al.Dielectric loss and impact energy accumulation of high frequency transformer insulation under rapidly repetitive pulsed voltages[J]. Transactions of China Electrotechnical Society, 2023, 38(5): 1206-1216.
[20] 赵义焜, 张国强, 韩冬, 等. 高频变压器用匝间绝缘材料沿面放电特性的实验研究[J]. 电工技术学报, 2019, 34(16): 3464-3471.
Zhao Yikun, Zhang Guoqiang, Han Dong, et al.Study on surface discharge characteristics of inter-turn insulation materials in high-frequency transformers[J]. Transactions of China Electrotechnical Society, 2019, 34(16): 3464-3471.
[21] 赵义焜, 张国强, 郭润睿, 等. 高频变压器用耐高温型匝间绝缘材料的击穿特性[J]. 高电压技术, 2020, 46(2): 657-665.
Zhao Yikun, Zhang Guoqiang, Guo Runrui, et al.Breakdown characteristics of heat-resistant inter-turn insulation materials in high-frequency transfor- mers[J]. High Voltage Engineering, 2020, 46(2): 657-665.
[22] 傅明利, 王威望, 赵小军, 等. 大功率高频变压器关键技术与发展趋势[J]. 高电压技术, 2024, 50(10): 4377-4387.
Fu Mingli, Wang Weiwang, Zhao Xiaojun, et al.Key issues and development prospects in high power high-frequency transformer[J]. High Voltage Engineering, 2024, 50(10): 4377-4387.
[23] 赵剑, 张哲, 李召端, 等. 三端口CLLC固态变压器的设计与优化[J]. 电工技术学报, 2024, 39(23): 7542-7553.
Zhao Jian, Zhang Zhe, Li Zhaoduan, et al.Design and optimization of three-port CLLC solid-state transformer[J]. Transactions of China Electrotechnical Society, 2024, 39(23): 7542-7553.
[24] 尚星宇, 庞磊, 卜钦浩, 等. 大功率高频变压器绝缘问题研究综述[J]. 中国电机工程学报, 2024, 44(8): 3306-3327.
Shang Xingyu, Pang Lei, Bu Qinhao, et al.Research review on insulation issues of high-power high- frequency transformers[J]. Proceedings of the CSEE, 2024, 44(8): 3306-3327.
[25] Li Zheqing, Zhao Chunyang, Hsieh Y H, et al.Partial fluctuating power control of resonant converter for solid-state transformer[C]//2022 IEEE Applied Power Electronics Conference and Exposition (APEC), Houston, TX, USA, 2022: 770-776.
[26] 蔡定国, 唐金权. 干式变压器用绝缘材料、绝缘结构与系统综述[J]. 绝缘材料, 2019, 52(11): 1-8.
Cai Dingguo, Tang Jinquan.Summary of insulating material, insulation structure and system for dry-type transformer[J]. Insulating Materials, 2019, 52(11): 1-8.
[27] 李思庚, 李庆民, 王伟, 等. 电热协同老化应力下环氧树脂复合材料沿面闪络特性与数值模拟[J]. 电工技术学报, 2025, 40(13): 4045-4057.
Li Sigeng, Li Qingmin, Wang Wei, et al.Character-ization and numerical simulation of epoxy resin composites flashed along the surface under electro-thermal co-aging stresses[J]. Transactions of China Electrotechnical Society, 2025, 40(13): 4045-4057.
[28] Manas C.Plastics Technology Handbook[M]. Boca Raton, FL, USA: CRC Press, 2018.
[29] Jaritz M, Biela J.Optimal design of a modular series parallel resonant converter for a solid state 2.88 MW/ 115-kV long pulse modulator[J]. IEEE Transactions on Plasma Science, 2014, 42(10): 3014-3022.
[30] 国家市场监督管理总局, 国家标准化管理委员会. 低压供电系统内设备的绝缘配合第1部分:原理、要求和试验: GB/T 16935.1—2023[S]. 北京: 中国标准出版社, 2023.
[31] 王争东, 曹晓龙, 杨淦秋, 等. 高压大功率IGBT用液晶环氧性能研究(二): 电气绝缘特性[J]. 电工技术学报, 2025, 40(3): 878-889.
Wang Zhengdong, Cao Xiaolong, Yang Ganqiu, et al.Research on properties of liquid crystalline epoxy for high-voltage and large-power IGBT (part 2): electrical insulation performance[J]. Transactions of China Electrotechnical Society, 2025, 40(3): 878-889. |
|
|
|
2026, Vol. 41 
