LAUSR

A zero-voltage switching topology for self-oscillating current-fed resonant inverter for wireless power transfer application is proposed. The drawback of conventional floating-capacitor connection between two differential MOSFET outputs is revealed. It turns out that the conventional connection causes severe switching loss because the MOSFET voltage has duty cycle >50%, while the current has an exact 50% duty cycle to sustain the self-oscillation. To solve the issue, the proposed self-oscillating inverter equips with two antiparallel diodes and two resonance capacitors between MOSFET output and ground, while the floating capacitor is removed. This allows dead-time of MOSFETs and zero-voltage switching, leading to significant reduction in switching loss. The operation and efficiency of the proposed circuit is demonstrated by simulation and measurements.