一种改进的混合比控制策略用于构网型与跟网型逆变器的无扰切换

With the rapid development of renewable energy generation, the proportion of power electronic equipment in the power system continues to increase, and its operating status presents complex and variable characteristics. In order to meet the various operation requirements and constantly provide stable operation conditions, in the renewable energy-dominanted power system, the renewable energy converter must have three key functions, which are working in grid following control (GFL), working in grid forming control (GFM) and realizing zero-disturbance switching between the GFL and GFM. This paper innovatively proposes an improved mixture ratio control strategy in order to meet the control challenges mentioned above. Different from the existing control strategy switching methods, the improved mixture ratio control strategy enables both control loops to operate in a closed loop at the same operating point by calculating the virtual current and virtual voltage, eliminating the generation of fluctuations from the root cause, and is also applicable to various typical GFM and GFL control methods. The stability analysis and simulation are both conducted to verify the feasibility and effectiveness of the proposed improved mixture ratio control for realizing the GFL, GFM, and zero-disturbance switch between them.