Mitigation of Bifurcation Effect in Wireless Power Transfer Systems Using a Tunable Fractional-Order Capacitor

In most cases, Wireless Power Transfer (WPT) systems

operate at the resonant frequency, as this condition

maximizes both transfer capability and efficiency. One

major challenge of WPT system under magnetic coupling

variation is the bifurcation phenomenon, which induces

resonant frequency splitting and consequently decreases

output power while narrowing the control range. This

paper presents a method to mitigate the bifurcation effect

through the use of a Fractional-Order Capacitor (FOC).

Compared to conventional tunable capacitors, the FOC

approach offers an additional degree of freedom, enabling

high-resolution control of capacitance. Simulation results

obtained from MATLAB/Simulink demonstrate that the

proposed FOC technique effectively eliminates

bifurcation by adjusting the duty cycle of the FOC

converter. Consequently, the output power is enhanced by

385% compared to a conventional system operating under

bifurcation conditions. The proposed method offers

strong theoretical validation of the FOC’s potential and

establishes a foundation for future practical

implementation.