Switching Device Dead Time Optimization of Resonant Double-Sided LCC Wireless Charging System for Electric Vehicles

Abstract

Aiming at the reduction of the influence of the dead time setting on power level and efficiency of the inverter of double-sided LCC resonant wireless power transfer (WPT) system, a dead time soft switching optimization method for metal–oxide–semiconductor field-effect transistor (MOSFET) is proposed. At first, the mathematic description of double-sided LCC resonant wireless charging system is established, and the operating mode is analyzed as well, deducing the quantitative characteristic that the secondary side compensation capacitor C2 can be adjusted to ensure that the circuit is inductive. A dead time optimization design method is proposed, contributing to achieving zero-voltage switching (ZVS) of the inverter, which is closely related to the performance of the WPT system. In the end, a prototype is built. The experimental results verify that dead time calculated by this optimized method can ensure the soft switching of the inverter MOSFET and promote the power and efficiency of the WPT.

Keywords

• inverter
• dead time
• soft switching
• resonant wireless charging
• electric vehicles