Abstract：High power-density inverters are continuously pursued, especially for renewable energy and electrified transportation applications. However, due to the performance bottlenecks of power devices, passive components, and heat sinks, the power density of existing inverters is not high. Some research on high power-density inverters has been explored, mainly focusing on high frequency and thermal management. However, the state-of-the-art power density of the inverter is challenged by unknown theoretical limitations and absent design guidelines. This paper details the theoretical limit, influence law, and improvement method of high power-density inverters, providing basic model and method guidance for designing, optimizing, evaluating, and applying high power-density inverters. Firstly, by establishing a characterization model of power density, the switching frequency limitation of power devices is characterized by considering the dead time, power dissipation, and thermal runaway issues. Based on the performance analysis of commercial products, the volume-specification principles of DC-link capacitors, filter inductors, and heat sinks are studied. Moreover, according to the interactive coupling among the passive component, heat sink, and power device, the power density limitation of the inverter is revealed. The factors that limit high power-density inverters are quantitatively described, including thermal resistance, maximum junction temperature, ambient temperature, power conversion efficiency, inverter component layout, and switching loss measurement. The power density improvement method of the inverter is proposed from the aspects of power device, circuit topology, thermal management, and structural design. For the forced air-cooled 50 kW renewable energy inverter, the volume of the filter inductor is the critical limitation of the high power-density inverter. In the 50 kW water-cooled vehicle motor controller, the ripple current-volume performance of the thin film capacitor is the key technical bottleneck that limits the high-power-density vehicle motor controller. Considering the coupling of multiple variables and factors, the influence of each variable on the power density can be regarded as the superposition of these influencing factors. To improve the power density of the inverter, the chip design and package design of power devices can be optimized from the structural, material, and process levels. In terms of circuit topology and thermal management, Si/SiC hybrid circuit, multi-level topology, soft switching circuit, advanced modulation algorithm, and active junction temperature control algorithm are used to reduce the switching loss of the device, improving the switching frequency of the power device and reducing the volume of the heat sink. The DC-link capacitor’s packaging structure and busbar’s structure are optimized. The following conclusions can be drawn. (1) The volume of the passive component is inversely proportional to the switching frequency, and the volume of the heat sink is proportional to the switching frequency. Therefore, the inverter has an optimal switching frequency, reaching the theoretical limitation of its power density. The power density limitation of the inverter can be further improved with breakthrough technology of power devices, passive components, and heat sinks. (2) The power density of the inverter is related to the maximum junction temperature, the thermal resistance of the package and the heat sink, the ambient temperature, the component layout, and the switching loss. Collaborative optimization of these multiple dimensions can improve the power density of the inverter effectively. (3) High-bandwidth and high-precision measurement techniques like wide-bandgap devices such as SiC, advanced packaging like double-sided cooling, high-heat flux heat-sink like impinging jet cooling, and optical isolation probes can be used to optimize inverter electro-thermal and reduce the volume of passive components and heat sink.
牛富丽, 曾正, 孙鹏, 邹铭锐. 逆变器功率密度的极限分析与提升方法[J]. 电工技术学报, 2025, 40(16): 5151-5163.
Niu Fuli, Zeng Zheng, Sun Peng, Zou Mingrui. Theoretical Limitation and Promotion Routine of Power Density for Inverter Application. Transactions of China Electrotechnical Society, 2025, 40(16): 5151-5163.
[1] 闫炯程, 刘天浩, 刘玉田, 等. 考虑新能源发电切换控制特性的直流输送能力快速评估[J]. 电力系统自动化, 2025, 49(7): 135-147. Yan Jiongcheng, Liu Tianhao, Liu Yutian, et al.Fast transfer capability assessment for HVDC considering switching control characteristics of renewable energy generation[J]. Automation of Electric Power Systems, 2025, 49(7): 135-147. [2] 王辰, 汤奕, 郑晨一. 基于动态优化周期的风光氢储耦合系统改进能量管理策略[J]. 电力系统自动化, 2025, 49(2): 142-153. Wang Chen, Tang Yi, Zheng Chenyi.Improved energy management strategy for wind-photovoltaic- hydrogen-storage coupling system based on dynamic optimization cycles[J]. Automation of Electric Power Systems, 2025, 49(2): 142-153. [3] 梅云辉, 宁圃奇, 雷光寅, 等. 车用高可靠性功率器件封装及辅助技术专辑主编述评[J]. 电源学报, 2024, 22(3): 15-21. Mei Yunhui, Ning Puqi, Lei Guangyin, et al.Editorial for the special issue on high reliability power device packaging and assistant technology in EV appli- cation[J]. Journal of Power Supply, 2024, 22(3): 15-21. [4] 王来利, 赵成, 张彤宇, 等. 碳化硅功率模块封装技术综述[J]. 电工技术学报, 2023, 38(18): 4947-4962. Wang Laili, Zhao Cheng, Zhang Tongyu, et al.Review of packaging technology for silicon carbide power modules[J]. Transactions of China Electro- technical Society, 2023, 38(18): 4947-4962. [5] 张少昆, 孙微, 范涛, 等. 基于分立器件并联的高功率密度碳化硅电机控制器研究[J]. 电工技术学报, 2023, 38(22): 5999-6014. Zhang Shaokun, Sun Wei, Fan Tao, et al.Research on high power density silicon carbide motor controller based on parallel connection of discrete devices[J]. Transactions of China Electrotechnical Society, 2023, 38(22): 5999-6014. [6] 林弘毅, 伍梁, 郭潇, 等. 高功率密度SiC静止无功补偿器强迫风冷散热综合建模及优化设计方法[J]. 电工技术学报, 2021, 36(16): 3446-3456. Lin Hongyi, Wu Liang, Guo Xiao, et al.A com- prehensive model of forced air cooling and optimal design method of high power density SiC-static var generator[J]. Transactions of China Electrotechnical Society, 2021, 36(16): 3446-3456. [7] Laird I, Yuan Xibo, Scoltock J, et al.A design optimization tool for maximizing the power density of 3-phase DC-AC converters using silicon carbide (SiC) devices[J]. IEEE Transactions on Power Electronics, 2018, 33(4): 2913-2932. [8] Reimers J, Dorn-Gomba L, Mak C, et al.Automotive traction inverters: current status and future trends[J]. IEEE Transactions on Vehicular Technology, 2019, 68(4): 3337-3350. [9] Zeng Zheng, Zhang Xin, Blaabjerg F, et al.Stepwise design methodology and heterogeneous integration routine of air-cooled SiC inverter for electric vehicle[J]. IEEE Transactions on Power Electronics, 2020, 35(4): 3973-3988. [10] 曾正, 邵伟华, 胡博容, 等. SiC器件在光伏逆变器中的应用与挑战[J]. 中国电机工程学报, 2017, 37(1): 221-232. Zeng Zheng, Shao Weihua, Hu Borong, et al.Chances and challenges of photovoltaic inverters with silicon carbide devices[J]. Proceedings of the CSEE, 2017, 37(1): 221-232. [11] Wen Xuhui, Fan Tao, Ning Puqi, et al.Technical approaches towards ultra-high power density SiC inverter in electric vehicle applications[J]. CES Transactions on Electrical Machines and Systems, 2017, 1(3): 231-237. [12] Biela J, Schweizer M, Waffler S, et al.SiC versus Si: evaluation of potentials for performance improvement of inverter and DC-DC converter systems by SiC power semiconductors[J]. IEEE Transactions on Industrial Electronics, 2011, 58(7): 2872-2882. [13] Kim K A, Liu Yuchen, Chen Mingcheng, et al.Opening the box: survey of high power density inverter techniques from the little box challenge[J]. CPSS Transactions on Power Electronics and Applications, 2017, 2(2): 131-139. [14] Gurpinar E, Castellazzi A.Single-phase T-type inverter performance benchmark using Si IGBTs, SiC MOSFETs, and GaN HEMTs[J]. IEEE Transactions on Power Electronics, 2016, 31(10): 7148-7160. [15] Drofenik U, Stupar A, Kolar J W.Analysis of theoretical limits of forced-air cooling using advanced composite materials with high thermal condu- ctivities[J]. IEEE Transactions on Components, Packaging and Manufacturing Technology, 2011, 1(4): 528-535. [16] Iradukunda A C, Huitink D R, Luo Fang.A review of advanced thermal management solutions and the implications for integration in high-voltage packa- ges[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020, 8(1): 256-271. [17] Acharya S, Anurag A, Bhattacharya S, et al.Perfor- mance evaluation of a loop thermosyphon-based heatsink for high-power SiC-based converter appli- cations[J]. IEEE Transactions on Components, Packaging and Manufacturing Technology, 2020, 10(1): 99-110. [18] Agbim K A, Pahinkar D G, Graham S.Integration of jet impingement cooling with direct bonded copper substrates for power electronics thermal manage- ment[J]. IEEE Transactions on Components, Packaging and Manufacturing Technology, 2019, 9(2): 226-234. [19] Whitt R, Huitink D, Emon A, et al.Thermal and electrical performance in high-voltage power modules with nonmetallic additively manufactured impinge- ment coolers[J]. IEEE Transactions on Power Elec- tronics, 2021, 36(3): 3192-3199. [20] 李恺颜, 曾正, 孙鹏, 等. 基于拓扑优化的车用功率模块Pin-Fin设计方法[J]. 电工技术学报, 2023, 38(18): 4963-4977, 4993. Li Kaiyan, Zeng Zheng, Sun Peng, et al.Topology optimization design of Pin-Fin for automotive power module[J]. Transactions of China Electrotechnical Society, 2023, 38(18): 4963-4977, 4993. [21] 刘海涛, 宋郭蒙, 向超群, 等. 计及均温性的高功率密度电力电子器件液冷散热优化研究[J/OL]. 电源学报, 1-12[2025-04-15]. https://link.cnki.net/urlid/12.1420.TM.20250703.1308.004. Liu Haitao, Song Guomeng, Xiang Chaoqun, et al. optimization of liquid cooling for high power density power electronic devices with consideration of tempera- ture homogeneity[J/OL]. Journal of Power Supply, 1-12[2025-04-15]. https://link.cnki.net/urlid/12.1420.TM.20250703.1308.004. [22] 姜翼展, 张经纬, 何凤有, 等. 一种开关损耗优化的Z源逆变器调制策略[J]. 电工技术学报, 2023, 38(16): 4312-4323. Jiang Yizhan, Zhang Jingwei, He Fengyou, et al.A switching loss optimization modulation strategy for Z-source inverter[J]. Transactions of China Electro- technical Society, 2023, 38(16): 4312-4323. [23] Ko Y, Andresen M, Buticchi G, et al.Discontinuous- modulation-based active thermal control of power electronic modules in wind farms[J]. IEEE Transa- ctions on Power Electronics, 2019, 34(1): 301-310. [24] Laloya E, Lucía Ó, Sarnago H, et al.Heat management in power converters: from state of the art to future ultrahigh efficiency systems[J]. IEEE Transactions on Power Electronics, 2016, 31(11): 7896-7908. [25] Volke A, Hornkamp M著; 韩金刚 (译). IGBT modules: Technologies, driver and application. IGBT模块: 技术、驱动和应用[M]. 北京: 机械工业出版社, 2017. [26] Wolfspeed. C2M0080120D datasheet[EB/OL]. www. wolfspeed.com/power/products/sic-mosfets, 2024-10-21. [27] Wintrich A, Nicolai U, Tursky W, et al.Application Manual Power Semiconductors[M]. Germany, Ilmenau: ISLE Verlag, 2015. [28] Bödeker C, Vogt T, Silber D, et al.Criterion for the stability against thermal runaway during blocking operation and its application to SiC diodes[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2016, 4(3): 970-977. [29] Buttay C, Raynaud C, Morel H, et al.Thermal stability of silicon carbide power diodes[J]. IEEE Transactions on Electron Devices, 2012, 59(3): 761-769. [30] TDK. Film capacitors[EB/OL]. www.product.tdk.com/en/products/capacitor,2024-10-21. [31] CDE. Polypropylene capacitors[EB/OL]. www.cde.com/resources/catalogs,2024-10-21. [32] Vishay. Metallized polypropylene film capacitor[EB/OL]. www.vishay.com/capacitors,2024-10-21. [33] Ruan Xinbo, Wang Xuehua, Pan Donghua, et al.Control Techniques for LCL-Type Grid-Connected Inverters[M]. Singapore: Springer Singapore, 2018 [34] Liu Yi, Huang Meng, Wang Huai, et al.Reliability- oriented optimization of the LC filter in a buck DC-DC converter[J]. IEEE Transactions on Power Electronics, 2017, 32(8): 6323-6337. [35] Zeng Zheng, Ou Kaihong, Wang Liang, et al.Reliability-oriented automated design of double-sided cooling power module: a thermo-mechanical- coordinated and multi-objective-oriented optimization methodology[J]. IEEE Transactions on Device and Materials Reliability, 2020, 20(3): 584-595. [36] Diao Fei, Du Xinyuan, Ma Zhuxuan, et al.A megawatt-scale Si/SiC hybrid multilevel inverter for electric aircraft propulsion applications[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2023, 11(4): 4095-4107. [37] Najjar M, Kouchaki A, Nielsen J, et al.Design procedure and efficiency analysis of a 99.3% efficient 10 kW three-phase three-level hybrid GaN/Si active neutral point clamped converter[J]. IEEE Transa- ctions on Power Electronics, 2022, 37(6): 6698-6710. [38] Jahnes M, Zhou Liwei, Fahmy Y, et al.A peak 1.2-MHz, >99.5% efficient, and >10-kW/L power dense soft-switched inverter for EV fast charging applications[J]. IEEE Transactions on Transportation Electrification, 2024, 10(3): 5520-5532. [39] 王要强, 李娜, 赵朝阳, 等. 一种新型多电平逆变器及其模块化分析[J]. 电工技术学报, 2022, 37(18): 4676-4687. Wang Yaoqiang, Li Na, Zhao Chaoyang, et al.A new type of multilevel inverter and its modular analysis[J]. Transactions of China Electrotechnical Society, 2022, 37(18): 4676-4687. [40] Liang Zhenxian, Ning Puqi, Wang F, et al.A phase-leg power module packaged with optimized planar interconnections and integrated double-sided cooling[J]. IEEE Journal of Emerging and Selected Topics in Power Electronics, 2014, 2(3): 443-450.
2025, Vol. 40 
