Robust Unity-Gain Transmitter-side Operation Mode in IPT Systems for Low Power Applications

Wireless power transfer has become a highly valued feature for users of portable electronic devices, which has contributed to a breakthrough in the improvement of this technology. In this paper, it is shown the analysis and implementation of two stable operation modes applied to low power inductive power transfer (IPT) systems. These operation modes do not require feedback from the receiver side because considers some parameters, such as the peak voltage across the compensation transmitter capacitor, to estimate the current through the resonant tank. The objective is to simplify the electronics required in IPT systems and to achieve proper operation, because this can be reflected in easy control, less time spent on designing with lower costs and shorter manufacturing time. In addition to the simplicity of the proposed systems, the build prototypes show high robustness to load variations thanks to the stability of the system when working at unity gain frequency.