Harmonic Mitigation of Variable Speed Drive with Shunt Active Filter Connected via LCL Coupler

Nowadays, the applications of nonlinear loads are extended to various types including variable speed drives, arc furnaces, computers and other electronic loads. These nonlinear loads generate harmonics, which cause excessive heating of conductors and pulsating torque of motors. This paper presents a shunt active filter used to mitigate the harmonic distortion produced by Variable Speed Drive (VSD) systems. A VSD load is connected at a certain bus in a simulated 14-bus Cigre benchmark distribution network. A shunt active filter is used to mitigate the VSD harmonics. The shunt active filter is controlled by a hysteresis controller and is coupled to the network through an LCL link. Harmonic analyses are performed using the fast Fourier transform and according to the IEEE Standard 519-2014. Three cases are considered: (i) no active filter; (ii) installing an active filter coupled to the network through an L link; and (iii) installing an active filter coupled through an LCL link. Simulation studies are performed by using the MATLAB/Simulink software. The results have shown that the shunt active filter with the LCL coupler reduces the harmonic distortion compared to the coupling through the L only.