One and two DC-links universal active power filter without series isolation transformer

This paper presents two universal active power filter (UAPF) configurations for reactive power and harmonic compensation without series isolation transformer. The proposed systems combine both series and shunt compensation, by using converters with one (configuration I) or two (configuration II) dc-links. They are suitable for applications in which size, weight and cost associated with transformers becomes a critical issue. The PWM techniques and complete control of the systems are developed. Simulation and experimental results are shown for validation purposes.