Single-Phase Universal Active Filter Without Transformer

This paper presents an universal active filter for harmonic and reactive power compensation in single-phase system. It is a combined system of a series active filter and a shunt active filter without use of transformer. The proposed system is suitable for applications where the size is a critical factor. The model of the system is derived and it is shown that the circulating current is an important objective in the converter design. A suitable control strategy, including the PWM technique, is developed. Simulated and experimental results are presented.