Universal Active Power Filter Based on AC-DC-AC Converter with Six Controlled Switches for Single-Phase Systems

This paper presents an ac-dc-ac converter with six controlled switches for single-phase systems applied as a universal active power filter (UAPF). The proposed topology is feasible for compensating voltages swells and harmonics generated by nonlinear loads. The difference between the conventional and proposed topology is the replacement of a controlled leg (composed of IGBTs) for an uncontrolled leg (composed only of diodes). For performance comparisons, current THD, switching and conduction losses of the semiconductors, average switching frequency, and power in the transformer were used as parameters. Control and pulsewidth modulation techniques based on space vector approaches were developed to eliminate zero-crossing distortions caused by the use of the uncontrolled leg. Simulation and experimental results were presented for validation of the mathematical model.