适用于中高压配电网的高功率密度谐振型级联H桥固态变压器

A High Power Density Resonance Cascaded H-Bridge Solid-State Transformer for Medium and High Voltage Distribution Network

现有中高压配电网固态变压器(SST)拓扑,其电容、模块、IGBT与高(或中)频变压器用量大,成本高,功率密度低。在现有级联型SST拓扑基础上,提出一种适用于中高压配电网的高功率密度谐振型级联H桥固态变压器(RCHB-SST)拓扑。RCHB-SST拓扑利用串联谐振的选频作用,实现了一台高频变压器对应多个H桥模块的特殊结构,较传统中高压配电网SST拓扑,能有效减少电容器、模块、IGBT和高频变压器用量以提高功率密度,同时模块的减少和DC-DC环节采用开环控制有利于控制系统的简化。分析RCHB-SST工作原理,建立RCHB-SST的数学模型,提出RCHB-SST的控制策略和模块电容值计算方法,并进行了仿真证明。

The existing topologies of solid-state transformer（SST） for distribution network require a large number of capacitors, modules, IGBTs and high-frequency（or medium-frequency） transformers, which leads to high cost but low power density. In this paper, a high power density resonance cascaded H-bridge（full-bridge） SST（RCHB-SST） for medium/high-voltage distribution network is proposed. Taken the advantage of frequency selection function of series resonance, RCHB-SST can achieve a special structure with one high-frequency transformer corresponding to several H-bridge modules. Compared with traditional SST topologies, it can enhance power density with fewer capacitors, modules, IGBTs and high-frequency transformers. Furthermore, fewer modules and the adoption of open-loop control in the DC-DC stage will simplify the control system. In this paper, the function principle of RCHB-SST is analyzed, the mathematical model of RCHB-SST is established, and the control strategies and the calculation method of module capacitance are proposed. Finally, simulation verification is carried out.