Investigation and analysis of switching ripple filters for three-phase four-wire Shunt Active Power Filter

There are many studies of Shunt Active Power Filters (SAPF) in the literature and applications of SAPF in industry while Active Power Filter (APF) has different topologies. SAPF is mostly preferred to be used as current source controlled, and used for compensating of harmonic currents, reactive power and unbalance of load current. Shunt APFs, which are acting as a current source, can also be used for the compensation of neutral current. Voltage Source Inverters (VSIs) are used while compensating these power quality problems. Since VSIs are fired by high switching frequencies, high frequency harmonics occur at point of coupling connection. Switching ripple filters are used to reduce the effects of high frequency harmonics. In this thesis, different switching ripple filters are investigated by constituting design and comparing their performances. In this thesis, LCL and LLCL filters are focused on. Besides, different passive and active damping methods are examined and compared with respect to damping capability and ripple suppresion performances. All controllers are written in Matlab Function block via C programming language. Accordingly, the results are obtained by using MATLAB/SIMULINK, it is observed that Switcihing Ripple Filters can mitigate switching ripples successfully through LCL and LLCL filter with different damping methods.