Improving the Power Quality of the Non-linear the Six-pulse Thyristor using a Shunt Active Filter based on Instantaneous Power Control Strategy

The cause of harmonics is the presence of nonlinear elements in the power system. Examination of harmonic issues led to research on the quality of electricity. Harmonic distortions are still the most important issue in electricity quality. Fortunately, not all power systems have a harmonic problem, and only a small percentage of feeders in electrical systems are affected by harmonic factors. In this paper, a three-wire thyristor-based rectifier load with a three-wire transformer structure is used to power the power supply while an active filter shunt to the instantaneous power theory control strategy is proposed to eliminate the harmonics generated by the rectifier loads. Also, the proposed design was simulated in MATLAB/SIMULINK software environment and finally, in order to prove its efficiency and effectiveness, it was compared with two important strategies of control conductive filter and conductive power filter. The simulation results show that the proposed strategy has less harmonic distortion of the entire network flow compared to the two methods, conductive power filter and controlled conductive power filter. According to the instantaneous power theory, first the active and reactive power of the harmonic power is calculated, the according to these values, the compensating currents proportional to this power are produced by the governing relations in d-q coordinates and injected into the network in shunt. Harmonic compensation currents in terms of size and phase are such that when they are collected by the load current, they eliminate the harmonic components of the current flowing to the network.