Comparison of the space vector current controls for shunt active power filters

A new space vector (SV) current control scheme for shunt active power filters (APFs) is introduced first, with a three-level neutral point-clamped voltage source inverter (VSI) as well as a standard two-level VSI. Then, the proposed control is compared with the other SV current control method to evaluate inherent advantages and drawbacks of the control schemes. The proposed control can selectively choose harmonic current components by using a real-time fast Fourier transform to generate the compensation current. The proposed current control utilises a rotating coordinate system, processing the information of the actual position of the grid-voltage SV, which is remarkably important in APF applications, and chooses switching states from the switching table implemented in a field programmable gate array. With the proposed control, the total harmonic distortion (THD) of the compensated grid current, the average switching frequency and switching power loss are significantly reduced. Different SV control strategies, including the proposed method, are compared via simulation and experiment, based on three-level and two-level VSIs.