| 引用本文: | 李 政,孙毅超,鄢寅宇,等.一种模块化多电平直流变压器的欠阻尼振荡抑制策略[J].电力系统保护与控制,2025,53(10):1-12.[点击复制] |
| LI Zheng,SUN Yichao,YAN Yinyu,et al.Underdamped oscillation suppression strategy for modular multilevel DC transformers[J].Power System Protection and Control,2025,53(10):1-12[点击复制] |
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| 摘要: |
| 模块化多电平直流变压器(modular multilevel DC transformer, MMDCT)原边侧串联的子模块电容、桥臂电感及寄生电阻之间存在欠阻尼特性，实际运行中易引发频繁且持续的欠阻尼振荡，给系统的安全可靠运行带来挑战。为改善系统的欠阻尼特性，首先，建立了模块化多电平直流变压器原边侧的环流等效模型，揭示系统欠阻尼振荡产生的机理。其次，引入小量修正角实现每隔半个开关周期对环流抑制电压的修正，主动控制环流变化趋势，有效增强系统内部阻尼，从而抑制了暂态过程中的欠阻尼振荡。然后，采用功率前馈-电容电压环流双闭环控制策略，通过合理的参数设计，确保系统在多场景多工况下具备良好的动态响应性能。最后，通过仿真和实验验证了所提控制策略对MMDCT欠阻尼特性的改善作用。 |
| 关键词: 模块化多电平直流变压器 欠阻尼振荡 振荡抑制 动态响应性能 |
| DOI：10.19783/j.cnki.pspc.241034 |
| 投稿时间：2024-08-07修订日期：2024-10-25 |
| 基金项目:国家自然科学基金项目资助(52277188) |
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| Underdamped oscillation suppression strategy for modular multilevel DC transformers |
| LI Zheng1,SUN Yichao1,YAN Yinyu1,YANG Xiong1,JI Zhendong2,LÜ Dan3 |
| (1. NARI School of Electricity and Automation, Nanjing Normal University, Nanjing 210023, China; 2. School of Automation,
Nanjing University of Science and Technology, Nanjing 210094, China; 3. Gaoyou Power Supply Branch,
State Grid Jiangsu Electric Power Co., Ltd., Gaoyou 225600, China) |
| Abstract: |
| The modular multilevel DC transformer (MMDCT) exhibits underdamped characteristics because of the primary side series-connected submodule capacitors, arm inductors and parasitic resistors. This often leads to frequent and persistent underdamped oscillations in actual operation, posing challenges to the safe and reliable operation of the system. To address this issue, an equivalent circulating current model of the primary side of the MMDCT is first established, revealing the mechanism behind the occurrence of underdamped oscillations. Second, a small correction angle is introduced to adjust the circulating current suppression voltage every half switching cycle, which actively controls the circulating current’s variation trend and effectively enhances the internal damping of the system, thus suppressing the underdamped oscillations in the transient process. A power feedforward-capacitor voltage and circulating current dual-loop control strategy is adopted. With proper parameter design, the system ensures good dynamic response performance in various scenarios and operating conditions. Finally, the effectiveness of the proposed control strategy in mitigating the underdamped characteristics of the MMDCT is verified through simulations and experiments. |
| Key words: modular multilevel DC transformer underdamped oscillation oscillation suppression dynamic response performance |
