摘要
基于SiC串联器件的双有源桥变换器因具有开关损耗小、功率密度高、能量控制简单等优势,有望成为中压变换场景中实现高频隔离的优选方案。为保证SiC串联器件的可靠均压,各器件上并联大容值缓冲电容,然而该设计使变换器在传输功率较低时难以实现零电压开通,严重影响变换器的整体效率和串联器件的可靠运行。该文通过构建SiC串联器件型中压双有源桥变换器多模态运行模型并深入分析其运行特性,提出一种基于等效励磁电感的无源软开关技术。所提技术可通过优化外接传输电感位置的方式实现中压侧等效励磁电感参数调节,从而在无额外控制前提下实现SiC串联器件的软开关范围扩展。最后,设计了4 kV/1 kV实验样机,实现了100 kW下运行。实验结果显示,所提出的软开关技术能显著地扩展变换器中SiC串联器件的软开关范围,在保证SiC串联器件均压稳定性的同时能够大幅降低变换器在轻载运行时的功耗。
The medium voltage(MV)dual active bridge(DAB)converter with series-connected SiC devices offers low loss and feasibility,making it attractive for high-frequency,high-compactness applications.However,voltage sharing across devices poses challenges.Large snubber capacitors reduce voltage imbalance but impede zero voltage switching-on(ZVS-on)under light load,increasing losses.Previous soft-switching techniques using active modulation or passive isolation tanks have complex implementation or redundant components.Therefore,this paper proposes a soft-switching technique using isolation tank parameter design and optimized external inductor positioning to extend the soft-switching range of series devices without additional components.To facilitate this technique,the T-type inductance network is equivalenced to aП-type inductance network.The equivalence reveals that the transmission inductance changes little versus the actual transmission inductance L_(k),while the equivalent magnetizing inductance L_(m1) depends on transmission inductance proportions on both sides.A lower transmission inductance proportion on the MV side makes L_(m1) closer to the actual magnetizing inductance L_(m).Based on voltage matching and dead time assumptions,six operational modes have been derived to calculate the characteristics of the converter.Mode boundary characteristics show that reducing L_(m1) increases the soft-switching range of the series-connected SiC devices.Regarding the transmission power characteristics,maximum transmission power barely changes with L_(m1).For the peak current characteristics,peak current rises with increasing transmission power,and it is recommended to avoid implementing the reference transmission power under high current peak values.Based on the analysis of the characteristics,this paper proposes design methods for key parameters.Firstly,the transmission inductance and voltage balancing capacitors are designed considering power regulation accuracy,maximum transmission power,and voltage imbalance sensitivity S_
作者
陈润田
李楚杉
姚文熙
李武华
何湘宁
Chen Runtian;Li Chushan;Yao Wenxi;Li Wuhua;He Xiangning(College of Electrical Engineering,Zhejiang University,Hangzhou,310027,China;Zhejiang University-University of Illinois at Urbana-Champaign Institute,Haining,314400,China)
出处
《电工技术学报》
EI
CSCD
北大核心
2024年第12期3732-3745,共14页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(51925702)
宁波市重大专项(2022Z026)资助项目。
