Protection Strategy for WPT Standby Mode Switching Based on LCL-S Topology Parameter Estimation

Wireless power transfer (WPT) has been often used for electric vehicle charging, underwater and mine power supply. In the actual power transfer process, the approach and departure between the transmitter (Tx) and the receiver (Rx) usually require additional detection and communication devices to achieve circuit protection and startup. Based on the circuit characteristics of LCL-S topology, this paper proposes a standby mode switching protection strategy without bilateral communication. When the Rx approaches, the Tx automatically identifies the load and coupling state and quickly switches the operating mode. When the Rx is removed, the Tx automatically maintains the standby mode in the low power state so that it can be restarted quickly. The proposed strategy only collects the electrical parameters of the Tx as the switching basis and does not need to add additional communication devices or detection coils, thus effectively reducing the volume and the transmission power consumption of the WPT system.