The Impact of Signal Delay and Power Surge on the Performance of Parity-Time Symmetric Wireless Power Transfer System

Parity-time symmetry wireless power transfer (PTS-WPT) technology enables constant output that is independent of load and mutual inductance, simply by controlling the zero-crossing points of the transmitting voltage and current. This approach is straightforward to implement and holds significant application potential. This article provides a detailed analysis of the power characteristics of the PTS system under strong coupling conditions and identifies a phenomenon unique to low-frequency tracking, referred to as the double-PTS (DPTS) state. The critical conditions for this phenomenon are calculated, and it is demonstrated that it leads to power fluctuations exceeding 50%. Additionally, the study examines the impact of signal detection delay-an unavoidable interference factor in practical scenarios-on the degradation of output power. Experimental results from the prototype show that the DPTS state can be effectively eliminated through parameter decomposition or optimization of the coupling mechanism. Furthermore, signal delay induces a 22% power fluctuation in low-frequency PTS systems and reduces the output power of high-frequency PTS systems by approximately 40% below the rated value. These experimental results are in good agreement with theoretical analyses.