三端口CLLC固态变压器的设计与优化  

Design and Optimization of Three-Port CLLC Solid-State Transformer

作　　者：赵剑 张哲[1] 李召端 宋伟波 Zhao Jian;Zhang Zhe;Li Zhaoduan;Song Weibo(State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology,Tianjin 300401 China)

机构地区：[1]河北工业大学省部共建电工装备可靠性与智能化国家重点实验室,天津300401

出　　处：《电工技术学报》2024年第23期7542-7553,共12页Transactions of China Electrotechnical Society

基　　金：省部共建电工装备可靠性与智能化国家重点实验室资助项目(EERI_KF2022004)。

摘　　要：为了解决三端口CLLC固态变压器(TP-CLLC-SST)设计中分布式谐振槽的谐振参数、谐振槽的阻抗匹配、死区时间与励磁电感的优化问题,该文提出一种应用于直流微电网系统中的三端口串联谐振型固态变压器的优化设计方法。TP-CLLC-SST由端口输入输出电容、全桥电路、分布式谐振槽和三绕组高频变压器组成。该变换器以固定的开关频率和接近于50%占空比开环运行,在整个负载范围内可以实现输入端口的零电压开关(ZVS)和输出端口的零电流开关(ZCS),进而可以简化系统控制,实现较高的效率。首先,该文提出了分布式谐振槽的阻抗匹配及谐振参数确定方法,提高了分布式谐振槽阻抗匹配度并简化了谐振参数设计过程,使得变换器的最大端口电压偏移率由5.6%降至1.02%,显著地提高了变换器的负载调节特性。其次,推导了变换器在不同运行模式及负载条件下分布式谐振槽输入输出电流有效值。并且,结合谐振槽电流有效值方程给出了死区时间和励磁电感的优化选择方法,有效地提高了该变换器在三种运行模式下的运行效率。最后,在搭建的三个端口电压分别为100 V、400 V和600 V,功率为1 kW的实验样机上验证了所提优化方法的可行性,并实现了98.3%的峰值效率。The three-port CLLC solid-state transformer(TP-CLLC-SST)consists of input and output capacitors,a full-bridge circuit,a distributed resonant tank,and a three-winding high-frequency transformer.The converter can be operated open-loop at a fixed switching frequency and close to 50%duty cycle.When the switching frequency is close to the resonant frequency,the LLC series resonant structure is commonly used in three-port solid-state transformers due to its many advantages such as soft switching over the full load range,inherent load regulation characteristics,high power density,high efficiency,and the ability to achieve open-loop operation.The TP-CLLC-SST can be applied in a DC microgrid system containing multiple renewable energy generation systems(RESs),energy storage systems(ESSs),and AC or DC loads to achieve efficient integration and control of RESs,ESSs,loads and the grid.The existing literature on the design method of resonant parameters for distributed resonant tanks of the TP-CLLC-SST is complex and unclear,the impedance matching degree of distributed resonant tanks is not high,and the dead time and magnetizing inductance of the converter in various operating modes has not been optimized.In order to solve the problems of determining the resonant parameters,the impedance matching of distributed resonant tanks and the optimization of dead time and magnetizing inductance,this paper proposes an optimized design method for the TP-CLLC-SST applied in a DC microgrid system.Firstly,the impedance matching and resonant parameter determination method of distributed resonant tanks is proposed in this paper.First,establish the equivalent characteristic circuit of the distributed resonant tanks of TP-CLLC-SST.Then,sequentially calculate the characteristic impedance of each port to one port,and calculate the equivalent characteristic impedance of each port.Finally,make the equivalent characteristic impedance of each port equal to obtain the characteristic impedance and resonant inductance relationship of each port.This meth

关 键 词：多端口固态变压器 分布式谐振槽阻抗匹配 CLLC串联谐振 软开关 

分 类 号：TM46[电气工程—电器]