A Direct AC-AC Single-Inductor Multiple-Output (SIMO) Converter for Multi-Coil Wireless Power Transfer Applications

In this paper, a new non-isolated AC-AC single-inductor multiple-output (SIMO) converter, which employs only one inductor in the power stage to perform a direct conversion from an AC power source into multiple independent AC output voltages without an intermediate DC link, is proposed. The proposed AC-AC topology has a simplified circuit structure, fewer components, increased power density, high efficiency, better scalability of a larger number of outputs, and low cost. A practical application of this converter is to drive multiple independent transmitter coils in a multi-coil Qi-compliant wireless charger to simultaneously charge multiple electronic devices. A hardware prototype of the AC-AC single-inductor three-output (SITO) converter is constructed and experimentally verified. The experimental results show that it can produce three sinusoidal-like outputs directly from the AC mains without noticeable cross-interference.