静止无功发生器在电压不平衡下的工作特性及其对不平衡电压的补偿

电网电压不平衡对并网的电力电子装置有着十分重要的影响.本文详细分析了采用传统控制方法时静止无功发生器(SVG)在电网电压不平衡下的工作特性.为了降低不平衡电压对SVG的危害及其对负载的影响,在SVG补偿无功的基础上,提出一种多目标补偿控制策略.当电网电压严重不平衡时,SVG就从补偿无功的功能切换到补偿电压不平衡的功能,扩展了SVG的功能.仿真和实验结果验证了该方法的正确性.

Operation and Control of Static Var Generator for Voltage Unbalance Mitigation

Voltage unbalance has a great impact on power electronics equipment. This paper provided a detailed analysis of SVG performance under unbalanced voltage with traditional control method. Furthermore, a novel control strategy was proposed to mitigate voltage unbalance and at the same time extend the functions of SVG. Besides compensating reactive power, SVG can also mitigate unbalanced voltage at the point of common coupling(PCC)when severe negative sequence voltage exists. The SVG operates as a voltage source controlled by the negative sequence voltage at the PCC. The relationships between all the parameters and the compensating characteristics were analyzed in detail. Simulation and experiment results verify the satisfactory performance of the SVG in mitigating voltage unbalance with the proposed control strategy.