Abstract This paper presents the nonlinear control design with formal stability proof for a Modular Multilevel Converter (MMC), which is critical for the interaction between AC and DC grids. Lyapunov theory is used to develop the proposed controller, which is based on Backstepping and Feedback Linearization techniques and to perform the stability analysis. The proposed controller allows to asymptotically stabilize all converter’s states, i.e., AC currents, circulating currents, and internal energy. The proposed algorithm allows to manage the converter in a wide range of operation points, by means of arbitrary tuning assignment. Robustness and performances of proposed control are verified by means of Matlab Simscape Electrical simulations, including active and reactive power reference variations and grid imbalance conditions. A detailed MMC switching model, of 450 MVA is considered on Matlab validation. A phase-shift PWM is considered, with a sorting algorithm. Also, a comparison with a standard PI controller is performed. In addition, MMC’s internal energy is also controlled, which can contribute to the high-speed frequency control by using this energy for synthetic inertia.

中文翻译：

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具有增强稳定性区域和任意闭环动态特性的模块化多电平转换器的非线性控制

摘要 本文介绍了模块化多电平转换器 (MMC) 的具有形式稳定性证明的非线性控制设计，这对于 AC 和 DC 电网之间的交互至关重要。Lyapunov 理论用于开发所提出的控制器，该控制器基于 Backstepping 和反馈线性化技术并执行稳定性分析。所提出的控制器允许渐近地稳定所有转换器的状态，即交流电流、循环电流和内部能量。所提出的算法允许通过任意调整分配在广泛的操作点范围内管理转换器。建议控制的稳健性和性能通过 Matlab Simscape Electrical 模拟进行验证，包括有功和无功功率参考变化和电网不平衡条件。在 Matlab 验证中考虑了 450 MVA 的详细 MMC 开关模型。考虑了具有排序算法的相移 PWM。此外，还与标准 PI 控制器进行了比较。此外，MMC 的内部能量也受到控制，可以将这些能量用于合成惯性，从而有助于高速频率控制。