China Railway First Survey And Design Institute Group Co.,Ltd
Project Supported by Shaanxi Province Industrial Science and Technology Research Project (No. 2016GY-066)
SVG（Static Var Generator，SVG）的无功调节功能依赖其网相位跟随能力，因此受锁相环节影响较大。当电网存在背景谐波、不对称运行等复杂工况时，基于系统电压锁相的方式需要设计正/负序提取、谐波提取等辅助环节，增加了系统的复杂度与非线性。基于此，本文提出了一种基于输出电流自锁相的SVG控制策略，在不添加辅助环节的前提下提高了SVG在复杂工况下的适应能力。首先，本文对SVG的控制策略与锁相方式进行了阐述，分析了不同工况下SVG的输出特性。然后，本文详细解释了所提自锁相方法的工作机理，论证了电流自锁相具备较好的环境适应能力，并通过bode图分析验证了所提策略具备良好的响应特性。最后，通过实验验证了理论分析的正确性。
The reactive power regulation function of Static Var Generator (SVG) depends on its phase following capability, so it is greatly affected by phase locking. When the grid has complex working conditions such as background harmonic and asymmetric operation, the phase-locking method based on system voltage needs to design auxiliary links such as positive/negative sequence extraction and harmonic extraction, which increases the complexity and nonlinearity of the system. Based on this, this paper proposes a SVG control strategy based on output current self-locking, which improves the adaptability of SVG under complex working conditions without adding auxiliary links. Firstly, the output characteristics of SVG are analyzed under different working conditions. Then, the realization mechanism of the proposed output current self-locking is explained in detail, and it is proved that the current self-locking has good adaptability to the environment. Then, the response functions of the traditional PLL link and the proposed strategy are deduced in detail, and the bode graph analysis verifies that the proposed strategy has good response characteristics. Finally, the correctness of the theoretical analysis is verified by experiments.