Comparative Performance Analysis of S–S and S–P Compensated WPT Circuits Supplied by a Six-Pulse Rectifier Under Grid Voltage Unbalance

This study aims to investigate the performance of wireless power transfer (WPT) circuits with S–S and S–P compensation topologies under unbalanced grid voltages. The studied WPT systems, fed by a three-phase uncontrolled six-pulse rectifier and a high-frequency inverter, are modelled in the time-domain using Matlab/SIMULINK. Voltage unbalance scenarios are generated considering two voltage unbalance factor (VUF) levels (2.5% and 5%), three positive-sequence voltage magnitudes (Vₚ = 0.90, 1.00, and 1.10 pu), and phase angle (θₙₚ) variations of the complex VUF from 0° to 315°. The performances of the systems are comparatively evaluated regarding efficiency (η), rectifier power factor (PF₆p), DC load voltage (Vo), voltage ripple ratio (ΔVo), current total harmonic distortion (THDI), and current unbalance factor (CUF). Results show that increasing VUF leads to higher THDI, CUF, and ΔVo levels while reducing PF₆p. An increase in Vₚ raises ΔVo in the system with S–S topology but reduces it in the system with S–P topology. Although higher Vₚ improves efficiency under unbalanced conditions, it worsens CUF and THDI. Performance indices exhibit oscillatory variations with respect to θₙₚ. Overall, the system with S–P topology shows lower sensitivity to voltage unbalance than the system with S–S topology.