35kV全SiC光伏发电单元中高频隔离变换器的寄生参数影响及抑制方法  

Influence of Parasitic Parameters and Its Suppression Methods of High Frequency Isolated Converter in 35kV All-SiC Photovoltaic Generation Unit

作　　者：史方圆 李睿 蔡旭 SHI Fangyuan;LI Rui;CAI Xu(Key Laboratory of Control of Power Transmission and Conversion,Ministry of Education,School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Minhang District,Shanghai 200240,China)

机构地区：[1]上海交通大学电子信息与电气工程学院电力传输与功率变换控制教育部重点实验室,上海市闵行区200240

出　　处：《中国电机工程学报》2020年第6期1787-1800,共14页Proceedings of the CSEE

基　　金：国家重点研发计划项目(2018YFB1500702);国家自然科学基金项目(51777124)。

摘　　要：光伏发电近年来呈现出大规模中高压接入的发展趋势。发展中压光伏发电单元有利于进一步提升系统效率,降低系统成本。随着效率与功率密度需求的进一步提升,SiC器件的使用成为必然。基于SiC器件的LLC变换器在高频应用中,寄生参数影响软开关实现。该文针对寄生参数的影响机理,进行系统的分析,针对产生机理,提出2种抑制寄生参数、促进软开关实现的解决方案:方案一通过减小变压器励磁电感,减少变压器二次侧开关寄生参数对变压器原边开关零电压开通实现的影响;方案二通过在变压器二次侧回路串联饱和电感,有效阻隔变压器二次侧开关寄生元件参与变压器原边元件谐振,从而确保变压器原边开关零电压开通。实验验证表明,理论分析与所提出的寄生参数抑制方法真实有效。Photovoltaic power generation has shown the development trend of large-scale medium or high voltage integration in recent years.The development of medium-voltage photovoltaic power generation units is necessary to further improving system efficiency and reducing system costs.Because of the requirements of higher efficiency and power density,the use of SiC devices becomes inevitable.In the high frequency application,parasitic parameters of secondary side SiC devices in LLC converter can influent the realization of soft switching.Aiming at the influence mechanism of parasitic parameters,this paper made a systematic analysis and proposed two solutions to restrain parasitic parameters and promote the realization of soft switching.The first scheme reduced the influence of parasitic parameters on LLC converter by reducing the magnetic inductance of transformer.Zero voltage switching(ZVS)can be guaranteed on primary side of transformer.In the second scheme,a saturable inductor was added to the secondary side to achieve ZVS on primary side.The saturable inductor can effectively prevent parasitic elements of secondary side from participating in resonance of primary side.The experimental results show that the theoretical analysis and the proposed parasitic parameter suppression methods are real and effective.

关 键 词：光伏发电单元 寄生参数 LLC变换器 ZVS软开关 饱和电感 

分 类 号：TM46[电气工程—电器]