Single-phase universal active power filter based on AC/AC converters

This paper presents four single-phase universal active power filters (UAPF) topologies with 4, 5, 6 and 7 legs. The proposed systems are based on AC/AC converters with two transformers. They are suitable to improve the harmonic distortion in the grid currents and a voltage compensation. The filter uses a combination of two series filters and one shunt filter sharing a single DC-link. The proposed active filters are capable of generating input and output voltages with low harmonic content and consists of low-power switches. The complete control system, including the PWM techniques based on vector approaches, is developed. Simulation and experimental results are shown for validation purposes.