High-Frequency High-Efficiency Isolated Resonant DC-AC Inverter

In this paper, an isolated DC-AC resonant power inverter topology, which employs a power transformer with inductive storage function, to provide galvanic isolation between the input and output ports, is investigated. To enable efficient high-frequency operation, zero-voltage-switching (ZVS) is achieved during the turn-on transients of the power switches on both primary and secondary sides by merely incorporating two additional resonant capacitors; while the secondary-side switch and diode achieve zero-current-switching (ZCS). Importantly, the addition of the resonant capacitor for the ZVS of the primary-side power switch also forms a lossless snubber resonant network to mitigate potential extremely high voltage spikes caused by the leakage inductance of the transformer. Compared to existing solutions, the proposed topology provides galvanic isolation for enhanced safety and protection, while maintaining high efficiency. A 1 MHz, 18 W prototype was designed and verified with a DC-AC power inversion efficiency of 90.39%.