Resonance and Impedance Matching for an Experimental Low-Frequency Wireless Power Transfer System

dResonance allows a wireless power transfer (WPT) system to operate at greater distances compared to a non-resonant one. However, frequency splitting is observed which has the effect of limiting the maximum power transferred. This paper proposes a simple impedance matching algorithm to eliminate the frequency splitting phenomenon and maximise the output power which is cheaper to implement than other impedance matching methods. The WPT system is first converted into an equivalent circuit. Then the necessary conditions to satisfy the critically coupled condition using L matching circuits are formulated, from which the impedance matching algorithm is developed. The latter is verified from simulation and experimental results which are compared, analysed and improvements are also proposed.