Source-Free Resonant Coupling for Cost-effective Wireless Power Transfer

Wireless power transfer (WPT) stands as a significant technological advancement, with numerous ongoing research endeavors. This paper introduces a novel approach termed 'source-free resonant' method in WPT system. In this methodology, a parallel inductor-capacitor pair, constituting the transmitter circuit, is initially charged with a direct current (DC) source. Subsequently, the DC source is disconnected, causing the pair to oscillate at it's natural frequency. Upon introducing another inductor-capacitor pair with the same natural frequency (the receiver circuit), resonance is induced, and the receiver efficiently absorbs the transmitted energy. After the receiver circuit absorbs all of the available energy, excluding resistive losses in the coil, a load is connected across the receiver, dissipating the received energy. The process is repeated for obtaining power periodically and the switching frequency required for this method is in kHz range. The detection of the highest received energy is done using a peak detector. As a result, complexities and challenges of adaptive tuning in conventional resonance inductive coupling are mitigated. Again, the use of DC source and low-frequency switching eliminates the cost of sophisticated high-frequency AC sources or inverters used in the conventional WPT circuits. The entire design and performance evaluation were conducted using Simulink MATLAB, yielding satisfactory results.