The Impact of Inverter Dead-Time in Single-Phase Wireless Power Transfer Systems

In this article, the effect of the dead-time on a single-phase wireless power transfer (WPT) system is studied in detail. In practice, the dead-time is always placed between the complementary switching pulses of the inverter phase-leg. At higher operating frequencies, the dead-time issues in the resonant inverter become critical, especially as the power level increases. The detailed analysis of the dead-time on a WPT system is discussed for different operating conditions of the inverter duty-cycle and power factor. The switching characteristics of the WPT system inverter are analyzed, and the notch phenomenon that appears at the output of the inverter is also discussed. A notch equation based on the observations is derived to predict the notch occurrence during the system operation. Furthermore, the mathematical expressions are presented for different notch conditions. Subsequently, the effect of the notches on the sensitivity and the power transfer of the series-series compensated WPT system is analyzed. Finally, the approach is verified experimentally on an 8-kW WPT system prototype, and the results are compared with the theoretical analysis.