Transient Voltage Injection Based Synchronization Method for Bidirectional Wireless Power Transfer Systems

In bidirectional wireless power transfer (BWPT) systems, synchronization between the active rectifier at the secondary side and the inverter at the primary side presents a challenge. This paper proposes a synchronization method based on transient voltage injection. The proposed method has low hardware requirements, without the need for voltage and current sampling, analog-digital converter (ADC), multipliers, or high-performance processors. Furthermore, the transient voltage injection method (TVIM) is immune to current harmonics and system detuning. The principle and implementation scheme of TVIM is introduced, where two magnetic rings are employed for transient voltage injection and detection. A pulse generator with simple control and low power loss is proposed. The signal processing circuit for transient voltage detection is investigated. Finally, experimental results demonstrate that the synchronization accuracy of TVIM can reach 0.2° and the dynamic response time is shorter than 30 μs,