A reference current control strategy based on Sogi and FBD method for shunt active power filter

When the grid voltage is not ideal, most of the reference current control strategies of shunt active power filter often fail or are too complex. In this regard, this paper proposes a reference current control strategy for shunt active power filter based on the second-order generalized integrator and FBD method. This method first uses a second-order generalized integrator to extract the fundamental component of each phase of the grid voltage and the corresponding orthogonal component, and then obtains the fundamental positive sequence component of the grid voltage based on the symmetric component method. Then, the FBD method is used to decompose the load current based on the fundamental positive sequence component of the grid voltage to obtain the reference value of the compensation current. This method does not require complex coordinate transformation, and the calculation is simple and the physical meaning is clear. Finally, experiments show that the method can also compensate for harmonic current, reactive current and negative sequence current in various complex grid voltage and load environments.