Power Control Strategy for Cascaded 3L-NPC Converters Considering Thermal Conditions
Power Control Strategy for Cascaded 3L-NPC Converters Considering Thermal Conditions
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DOI：
10.1109/ieses53571.2023.10253741
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发表时间：
2023-07
期刊：
影响因子：
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通讯作者：
Jinlei Chen;Wenlong Ming;Sheng Wang;Jun Liang;I. Lüdtke
中科院分区：
文献类型：
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作者：
Jinlei Chen;Wenlong Ming;Sheng Wang;Jun Liang;I. Lüdtke
级联三电平中性点箝位（C3L-NPC）变流器最近被用于中压直流（MVDC）配电网，例如英国北威尔士的ANGLE-DC项目。与同类mmc相比，C3L-NPC转换器的主要优点是成本低得多。本文提出了考虑结温条件的该类变换器的功率控制策略。首先，设计了一个带直流电压平衡控制器的功率控制环，用于控制输出功率并同时稳定子模块的直流电压。在此基础上，提出了一种考虑钢结构间热应力不平衡的热调节方法。通过热调节，使系统的热应力均匀分布，提高了系统的可靠性。提出了一个包括电气元件和热元件的系统模型。控制器的参数整定是基于系统极点的位置进行的。最后通过PLECS仿真和实验验证了所提控制策略的有效性。
Cascaded three-level neutral-point-clamped (C3L-NPC) converters have been recently adopted in medium-voltage direct-current (MVDC) distribution networks, such as in the ANGLE-DC project in North Wales, UK. Compared with its counterpart MMCs, the C3L-NPC converters' main advantage is the much lower cost. This paper presents a power control strategy for this type of converter considering junction temperature conditions. Firstly, a power control loop with a DC voltage balancing controller is presented, to control the output power and stabilize the DC voltages of submodules (SMs) concurrently. Then, a thermal regulation method is proposed considering the unbalanced thermal stresses among SMs. By means of thermal regulation, the thermal stresses are equally shared among SMs, which enhances the system reliability. A system model which includes both the electrical and thermal elements is presented. The parameter tuning of the controllers is performed based on the system pole placement. The effectiveness of the proposed control strategies is finally verified by PLECS simulation and experimental tests.