多虚拟同步机系统的自适应滑模变结构控制方法

虚拟同步机是一种可以改善分布式能源并网兼容性的技术手段。目前有关虚拟同步机滑模控制的研究大多数仅针对于单机系统。由于单机系统无需考虑多机系统中出现的虚拟惯量等参数之间的耦合影响，这导致现有的滑模变结构控制策略不适用于多虚拟同步机系统，当功率波动时系统频率有可能产生振荡。针对上述问题，提出了多虚拟同步机虚拟惯量的整定判据，并基于整定判据提出多虚拟同步机系统的自适应滑模变结构控制策略，可以使系统中各台机组在扰动状态下输出稳定频率。通过自适应滑模变结构控制策略使得多虚拟同步机组在功率波动时输出稳定的频率，从而避免系统频率失稳。最后，通过搭建PSCAD仿真模型验证了理论分析的正确性及有效性，所提控制方法可提高多虚拟同步机系统的稳定性与鲁棒性。

Adaptive sliding mode variable structure control for multi virtual synchronous machine systems

The virtual synchronous machine is a technical means to improve distributed energy grid connection compatibility. Currently, most research on sliding mode control of a virtual synchronous machine is only for single-machine systems. The single-machine system does not need to consider the coupling effect between the virtual inertia and other parameters in the multi-machine system. As a result, the existing sliding mode variable structure control strategy is not suitable for multi virtual synchronous machine systems, and the system frequency may oscillate when the power fluctuates. In this paper, a tuning criterion of virtual inertia of multi virtual synchronous machines is proposed, and an adaptive sliding mode variable structure control strategy is proposed based on the tuning criterion. This can make each unit in the system output have stable frequency in the disturbed state. The strategy stabilizes the output frequency of multi virtual synchronous units when the power fluctuates, to avoid system frequency instability. Finally, the correctness and effectiveness of the theoretical analysis are verified by building a PSCAD simulation model. The proposed control method can improve the stability and robustness of the multi-virtual synchronous machine system.