A large-capacity harmonic current widely exists in low-voltage distribution networks, which seriously affects the operation reliability and the efficiency of power system and related equipment. Due to its excellent controllability and dynamic response performance, the full-controlled semiconductor-device-based multimodular shunt active power filter is considered as the optimal choice to compensate the distorted current from large-scale nonlinear loads. However, due to the increase of parallel modules, comprehensive compensation performance needs to be improved and the system stability analysis is required. In this article, based on the comprehensive comparison and the analysis of the traditional parallel operation, a novel dual-loop-based harmonic control strategy that features the comprehensive filtering performance through combining feedforward power splitting and feedback frequency splitting control is proposed, which realizes a comprehensive optimization of capacity utilization, compensation precision, and dynamic response performance. In addition, for the system stability analysis, by establishing the two-port Norton equivalent circuit of a multi-inverter parallel system in the admittance form, the response expressions of each part of parallel system are obtained, and the essential reason for the instability is revealed from the perspective of the frequency-domain characteristics of global admittance. Finally, simulation and experimental results are presented to support the reasonability and effectiveness of the proposed method.

中文翻译：

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多模块并联 SAPF 系统的基于双环的谐波电流控制策略和导纳建模


低压配电网中广泛存在大容量谐波电流，严重影响电力系统及相关设备的运行可靠性和效率。由于其优异的可控性和动态响应性能，基于全控半导体器件的多模块并联有源电力滤波器被认为是补偿大规模非线性负载畸变电流的最佳选择。但由于并联模块的增加，综合补偿性能需要提高，并且需要进行系统稳定性分析。本文在对传统并联运行进行综合比较和分析的基础上，提出了一种前馈功率分流与反馈频率分流控制相结合的综合滤波性能的双环谐波控制策略，实现了容量利用率、补偿精度、动态响应性能综合优化。此外，对于系统稳定性分析，通过建立导纳形式的多逆变器并联系统的二端口诺顿等效电路，得到并联系统各部分的响应表达式，得出不稳定的本质原因为从全局导纳的频域特性的角度揭示了这一点。最后，仿真和实验结果证明了所提方法的合理性和有效性。