以双有源全桥(Dual Active Bridge, DAB)变换器为基础构成的直流变压器优势显著,在未来多电压等级的直流配电网中具有广泛的应用前景。现有研究缺乏直流变压器的潮流建模和等值电路模型。首先,推导了DAB在输入串联输出并联(input-series output-parallel, ISOP)结构下的直流变压器稳态数学模型,分析了移相比在直流配电网潮流计算中的作用。其次,针对多个直流变压器潮流求解时间长的问题,推导出π型等值电路模型并基于此提出了边缘优先和模型等效的方法,能够快速、准确的计算含多个直流变压器的多电压等级直流配电网潮流,大大缩短了潮流求解的时间。最后,利用修改后的IEEE14节点直流配电网验证了所提模型和方法的正确性和有效性。
英文摘要:
The advantages of DC transformers based on dual Active Bridge (DAB) converters are outstanding, and they have broad application prospects in DC distribution networks with multiple voltage levels in the future. Existing research lacks the power flow modeling and equivalent circuit model of DC transformers. Firstly, the steady-state mathematical model of the DC transformer under the input-series output-parallel (ISOP) structure is derived, and the effect of the shift on the power flow calculation of the DC distribution network is analyzed. Secondly, for the problem of long time of multiple DC transformers, the π-equivalent circuit model is derived and an edge-first and model-equivalent method is proposed. It can quickly and accurately calculate multiple voltages with multiple DC transformers. The gradual DC distribution network trend greatly shortens the time for tidal current solution. Finally, the correctness and effectiveness of the proposed model and method are verified by the modified IEEE 14-node DC distribution network.