基于钳位开关电容的高频模块化直流变压器

High-frequency Modular DC Transformer based on Clamping Switched Capacitors

直流变压器是构建直流配电网的核心设备。鉴于此,为了促进直流配电网的工程化进程与运行可靠性,提出一种基于钳位开关电容的高频模块化直流变压器方案(clamping switched capacitors-based high-frequency modular DC transformer,CSC-DCT)。相比于传统的直流变压器,该文所提的方案不仅集成了原有方案的功率密度高、体积小、运行噪音低、高低压侧隔离等优点,同时也克服了原有方案应用时的众多不足,是一个集冗余子模块设计功能、直流故障处理能力、灵活控制方法、升降压型高频链电压调节能力以及单步直接电压变换功能于一体的换流开关一体化直流变压器。同时,为了更好地利用CSC-DCT的优势,对CSC-DCT的子模块基本调制策略、直流故障处理策略、冗余子模块在线切换策略、控制系统架构及电流、电压以及传输功率特性等进行详细的分析与研究。实验结果验证了该文所提的CSC-DCT及其控制策略的可行性与有效性。

DC transformer(DCT)plays a key role in DC distribution grid.And to promote the engineering process and reliability of dc distribution grids,a novel clamping switched capacitors-based DC transformer(CSC-DCT)was proposed in this paper.Comparing with traditional DCT,the proposed CSC-DCT not only integrates the advantages of high power density,small volume,low noise,and current isolation between high and low voltage side,etc,but also overcome the defects of the traditional schemes.In fact,CSC-DCT is a great and feasible DCT topology with redundant sub-modules design,DC fault handling ability,flexible control method,buck-boost high-frequency-link voltages regulating ability and single-step DC voltage conversion.That is to say,CSC-DCT is a DCT integrated with converter and breaker.And to exploit the advantages of CSC-DCT to the full,the control system architecture,SM modulation strategy,DC fault isolating and recovering operation,redundant SM cuts out/in strategy,as well as the voltage,current and power characterization were proposed and analyzed in the paper.The detail experiment results validate the correctness and effectiveness of the analysis.