Dynamic Optimization Method of Distributed Harmonic Compensation Based on Active Device Margin Calculation Model of APF

With rapid development of power electronics industry, a number of nonlinear devices are connected to the power grid, and the grid voltage suffers from severe harmonic pollution. For the treatment of harmonic voltage, the equipment adopted is Active Power Filter(APF), which can detect the harmonics at the installation point. However, the harmonic sources at each node will vary with time, requiring the injection of new harmonic compensation commands, while also considering the surplus of APF active devices to ensure efficient and stable operation of APF. This paper aims to propose a dynamic adjustment method of distributed harmonic compensation based on the calculation model of active device margin of APF. Firstly, the APF active device loss and injection temperature model is established under different harmonic combinations to calculate in real time whether the harmonic injection command meets the active device margin. Moreover, for the power grid with the harmonic source changes, the particle swarm optimization algorithm is used to obtain new harmonic injection commands, which on one hand reduces the total voltage harmonic distortion rate of the power grid, and on the other hand meets the active device margin to ensure stable operation of APF.