A novel control technique for stable operation of four-leg shunt active power filters in electrical grids

The main goal of this study is the use of Lyapunov's stability theory to a three-phase four-wire shunt active power filter (SAPF), since this method has been applied effectively to other areas of converter. The dynamic model of the SAPF is first established, after that, a combination of fuzzy tracking control and Lyapunov function is suggested in order to impose a desired transient waveform on the considered three-phase four-wire distribution grid, providing robustness and insensitivity to parameter changes. Furthermore, the suggested control technique guarantees appropriate tracking of the reference current components and simplifies the global control design. The feasibility of the suggested control method is validated using comprehensive simulation studies on a four-wire SAPF in order to compensate for nonlinear and unbalanced grid-connected loads in an electrical power distribution network.