Active power filter based on dual-converter topology

The paper presents a concept of a shunt active power filter (APF), which is able more precise mapping of its input (power grid) current in a reference signal, compared to a typical filter solution. It can be achieved by means of such interconnection of two separate converters that one of them corrects a total output current towards a reference signal. An output power of auxiliary converter is much lower than an output power of main one while its frequency response is extended. Thanks to continuous work of an auxiliary converter also pulse modulation components in an APF input current are minimized. These benefits are paid for by a relatively small increase in the complexity and the system cost. This concept of the converter has been called the dual-converter topology (DCT). In the paper both, DCT and APF basics, simulation experiments, and possible practical arrangement of the active filter are presented.