Operating Frequency Insensitive to Coupling Variations in PT‐Symmetric CPT Systems

ABSTRACT Maintaining a stable operating frequency while achieving robust power delivery remains a challenge in parity–time (PT)‐symmetric wireless power transfer systems, particularly under variable coupling conditions. While self‐oscillating PT‐symmetric inductive power transfer (IPT) systems can track bifurcation frequencies to sustain power delivered to the load (PDL), their operating frequency varies significantly with coupling, limiting practical applicability. This paper demonstrates that in capacitive power transfer (CPT) systems, one bifurcation frequency remains largely insensitive to coupling variations—a unique property attributed to the fact that the self‐capacitance and the corresponding resonant frequency vary with the mutual‐capacitance. We propose a frequency selection method that enables the system to operate persistently at this stable high‐frequency branch. Experimental results confirm that the implemented CPT system operates within 490–500 kHz across varying coupling conditions, while maintaining a stable PDL and power transfer efficiency of over 75% (up to 90% under optimal loads). This approach offers a viable solution for applications requiring both frequency stability and efficient power transfer.