Authors : Kiran Reddy Masarla

Volume/Issue : Volume 11 - 2026, Issue 4 - April

Google Scholar : https://tinyurl.com/2xpdc2z8

Scribd : https://tinyurl.com/23vtm724

DOI : https://doi.org/10.38124/ijisrt/26apr633

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Abstract : This paper presents a comprehensive simulation study of a stand-alone three-phase four-leg voltage source inverter (VSI) operating under both linear and non-linear load conditions. The conventional split-capacitor three-phase three-leg inverter topology suffers from inherent voltage imbalance issues and requires bulky capacitor banks, whereas the four-leg topology eliminates these drawbacks by providing an independent neutral current path. Two control strategies are investigated: the proportional-resonant (PR) controller and the proportional (P) controller, both implemented within a dual-loop voltage and current regulation framework. The space vector pulse width modulation (SVPWM) technique, realized via an offset voltage injection approach, is adopted as the switching modulation scheme. Simulation results are presented and analyzed for balanced resistive (R) loads, unbalanced R loads, balanced and unbalanced resistive-inductive (RL) loads, and non-linear diode-rectifier loads. Performance indices including total harmonic distortion (THD), RMS load current, and neutral current magnitude are evaluated and compared across all loading scenarios.

Keywords : Three-Phase Four-Leg VSI; Proportional-Resonant (PR) Control; SVPWM; Balanced Loads; Unbalanced Loads; Non-Linear Loads; LC Output Filter; Neutral Current Compensation; THD Analysis.

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