Three-Phase Three-Leg Four-Wire High Power Factor Converter Addressing the Problem of Unbalanced DC Link Capacitor Voltages

High Power Factor Converters are widely utilized in several industrial sectors owing to the significant advancements in high-power electronics. Power pollution arises from the presence of nonlinear loads and imbalanced sources, leading to a decline in power quality. Non-sinusoidal balanced or unbalanced current leads to the generation of harmonics, excessive neutral current, reactive power, and unbalanced loads on the mains. These problems are mostly observed in multilevel inverters where the capacitor unbalances are routine due to their operation and switching involved that too on Diode Clamped MLI. To address these issues in DCMLI, numerous methods have been suggested to achieve equilibrium in the voltage of the DC side capacitor, while also maintaining balanced sinusoidal source currents. The Synchronous Reference Frame (SRF)-based Zero Current Injection (ZCI) approach is proposed for attaining balanced DC link capacitor voltages in a three-phase three-leg four-wire topology. This algorithm is designed to address unbalanced load and supply voltage circumstances.