Three-Phase-Input Inductive Wireless Power Transfer System for Rectifier-Output Voltage Ripple Reduction

Single-phase inductive wireless power transfer (WPT) systems based on direct AC–AC conversion eliminate the intermediate stiff DC link but retain a grid-frequency-dependent envelope in the generated high-frequency AC (HFAC) voltage. After secondary-side rectification, this envelope results in a large low-frequency rectifier-output voltage ripple and a wide voltage variation range, requiring any downstream regulation stage to accommodate a correspondingly wide input-voltage range. To address this issue, this paper proposes a half-bridge direct matrix converter (HBDMC)-based three-phase-input WPT system using three HBDMC modules and series-connected high-frequency transformers. By aligning the HFAC voltage polarity sequences according to the instantaneous grid-voltage polarities, the transformer secondary-side voltages are constructively superimposed, producing a low-frequency six-pulse envelope instead of the conventional two-pulse envelope. At a grid phase-voltage RMS of 100 V, the measured rectifier-output voltage ripple factor decreases from 51.69% (single-phase) to 6.65% (three-phase), and the normalized voltage-range ratio from 98.51% to 20.57%, representing reductions of 87.1% and 79.1%, respectively. At input voltages of 50, 75, and 125 V, the three-phase ripple factors remain within 6.48–7.58%, compared with 50.62–59.86% for single-phase operation. These results confirm substantial low-frequency rectifier-output ripple suppression and voltage-range narrowing through the proposed three-phase architecture under the investigated conditions.