Effective Harmonic Cancellation Technique for a Three-Phase Four-Wire System

An excess non-linear and unbalanced load application increases the power quality (PQ) problem by injecting harmonic current. The avoidance of neutral current control creates additional PQ problems due to excess circulating current in modern 3 phi 4W applications. Therefore, this manuscript suggests improved alpha beta transform-based voltage and current control approaches for both 3 phi 3W and 3 phi 4W shunt active filter (SAF) applications. In the proposed approach, a novel combined voltage and current (NCVC) control approach is presented for modern 3 phi 3W systems by using voltage and closed-loop current controllers. However, due to the absence of a neutral current, the NCVC is not sufficient for 3 phi 4W system application. Therefore, by considering the current reference parameter generated from the NCVC, a novel harmonic compensation technique (NHCT) is proposed with proper mathematical expressions for the 3 phi 4W application. To show the importance of NHCT over traditional P-Q-R control, the developed MATLAB/Simulink model is tested by using different 1 phi and 3 phi) nonlinear/unbalanced load conditions. The comparative results indicate that, by using NHCT, the 3 phi 4W system contains a lesser total harmonic distortion (THD) and harmonic mitigation ratio (HMR), less ripple frequency, an improved power factor, a lesser neutral current, and a balanced active/reactive power condition. From the above comparative analysis results, it is found that the overall improvement percentage is 66.78%. The above findings justify the significance of the NCVC and NHCT approach during both unbalanced and non-linear load-based 3 phi 4W applications.

Automated summary

This paper investigates the solution to power quality problems caused by non-linear and unbalanced load in three-phase four-wire applications. Improved voltage and current control methods are proposed, along with harmonic compensation techniques, to reduce total harmonic distortion and ripple frequency, and improve power factor and energy balance.