中压直流配电网中直流变压器工程化应用

文中针对中压直流配电网中直流变压器(DCT)的工程化应用问题,首先归纳实际工程对DCT故障快速恢复、高可靠供电及灵活控制的需求,采用带有隔离半桥的改进型子模块结构,分析其故障阻断、在线冗余、有载调压及均压控制功能。然后,讨论子模块取电方式、整机启动策略及绝缘设计等典型工程问题,比较多种解决方案并进行适应性分析。进一步,重点研究能效提升方法这一工程核心问题,分析硬件及软件上的能效提升措施,并分别从材料选型、高频变压器设计、控制策略改进、系统用能优化等方面提出相应优化策略。最后,探索小型化应用的工程推广前景,从特定场景设计、模块拓扑改进、新型材料应用3个角度分别提出一种小型化方案,阐明现有技术瓶颈并提出相应解决思路。

Engineering Applications of DC Transformer in Medium-voltage DC Distribution Network

Focusing on the problems of engineering applications of DC transformer(DCT)in medium-voltage DC distribution network, this paper firstly summarizes the requirements of DCT for practical engineering applications, such as quick recovery form fault, high reliability for power supply and flexible control. An improved submodule topology with isolated half bridge is adopted, and the fault blocking, on-line redundancy, on-load voltage regulation and voltage sharing control of the improved submodule topology are analyzed. Then, several typical engineering problems are discussed, including the power supply mode for submodules, soft start-up strategy and insulation design. Various solutions for these problems are further presented and compared with the adaptability analysis. Furthermore, the energy efficiency improvement which is the key issue for engineering is mainly studied by the analysis of hardware and software. And the corresponding improvement strategies are proposed in several aspects, which include the type selection of materials, design of high frequency transformer, improvement of control strategy and optimization of system energy. Finally, the engineering prospects of miniaturized apparatus are explored. Several schemes for miniaturized apparatus are respectively proposed from the perspectives of specific scenario design, improvement of module topology and application of new materials, and the existing technical bottleneck and corresponding solutions are clarified.