Transformer less SLC for harmonic reduction in non linear load applications

Abstract

The significant issue with industry and domestic applications is the remarkable performance indices of devices due to poor power quality. The sheer cause of above cited issue is the presence of harmonics introduced in the line current. There are many background reasons of harmonics generation; one of them is the extensive use of non-linear loads in our daily life utility. In this work, an appropriate shunt active filter is designed to generate the current which is equal in magnitude and opposite in phase to the harmonic component of line current. The main source converter, operating for rectification, is actually acted as a nonlinear load for mains. Therefore, a semiconductor switching device is employed to design a voltage source inverter. It is connected in parallel to the main source converter. The gate pulse of the switching device is controlled using a PID controller. The preciseness of the attempt is synchronized parametrically to get the line current becomes free from harmonics and sustain sinusoidal shape. The complete concept is modelled and simulated on MATLAB software. It is observed that initially with linear load the line current is sinusoidal with .02% THD. When a non-linear load is connected to the same supply, the line current becomes distorted with 92.32%THD, which is reduced significantly through proposed methodology to 0.49%. This falls under the permissible limits of acceptable distortion as per IEEE standard 519.