Design and Research of Wireless Power Transfer System Based on Parity-Time-Symmetric

The traditional Wireless Power Transfer (WPT) system has the problem that the coupling coefficient has a great influence on the transmission characteristics. The WPT system with PT-symmetric structure can achieve the transmission characteristics independent of the coupling coefficient and maintain stable power and efficiency transmission in the strong coupling region constructed by the PT-WPT system. To further optimize PT-WPT, this paper proposes a PLL controlled wireless power transfer system based on PT-symmetric theory. Phase-locked loop (PLL) is employed to accurately control the power of the transmitter and the system can maintain constant transmission power and efficiency in the strong coupling region. In addition, this control method also reduces the complexity of WPT system. A 10–15 W experimental WPT system platform with a 0–10 cm transmission distance is developed to validate the transmission power and efficiency of the system, The results demonstrate that the output voltage and current of the inverter can always ensure that the system works in the PT-symmetric state and the transmission efficiency is more than 90%, The transmission power is not less than 10 W within the transmission range of 0–10 cm. The designed system can maintain constant high efficiency and high-power transmission in the strong coupling region.