International Journal of Scientific Research and Engineering Development

The growing penetration of power‑electronic interfaces in industrial and renewable energy systems necessitates high quality power conversion. Conventional three‑phase voltage source rectifiers (VSRs) employing sinusoidal pulse-width modulation often suffer from poor input power factor and significant current harmonics that deteriorate power quality. To address these issues this paper proposes a modified control scheme combining a double-decoupled synchronous reference frame (DDSRF) phase-locked loop (PLL) with an enhanced space vector pulse-width modulation (SVPWM) algorithm. The DDSRF-based approach eliminates cross‑coupling between the positive and negative sequence components of the grid, thereby suppressing second harmonic oscillations under unbalanced conditions. An outer voltage‑oriented control (VOC) loop regulates the dc-link voltage while inner current loops adopt decoupling and feed-forward terms to improve dynamic response. A modified SVPWM modulator maximises dc-bus utilisation and reduces switching losses. Detailed mathematical modelling of the VSR is presented in abc and dq frames, highlighting the decoupling strategy. Simulation studies carried out on a 22.5 kW prototype demonstrate that the proposed controller achieves nearly unity power factor and reduces input current total harmonic distortion (THD) to around 1 %. Comparisons with conventional VOC show superior transient performance and reduced overshoot in dc-bus voltage. The work contributes to the development of robust active front-end converters for applications requiring stringent power quality compliance.