Study And Implementation Of Dynamic Tuning Algorithm Of Resonant Wireless Power Transfer System

Magnetically coupled resonant wireless power transfer is a new type of power transmfer technology.Compared with the traditional inductive wireless power transfer technology,the magnetic coupling resonant wireless power transfer technology has a longer transfer distance between the transmitting device and the receiving device.The sensitivity of misalignment is smaller,so there are a large number of institutions currently studying the technology.The magnetically coupled resonant wireless power transfer system operating in the resonant state is the premise for efficient power transfer.In the actual production environment,the wireless power transfer system is not easy to work in the resonance state due to factors such as load changes and environmental interference,this results in a reduction in output power and transfer efficiency.In order to solve the problem of detuning of resonant wireless power transfer system and improve the stability of the system,this thesis designs the equivalent capacitance circuit and the corresponding tuning algorithm.The specific work contents are as follows.Based on the circuit theory,the basic topology of the wireless power transfer system is analyzed,and the factors affecting the output power and transfer efficiency of the wireless power transfer system are obtained.The influence of the detuning of the transmitting end and the receiving end of the resonant wireless power transfer system on the output power and transfer efficiency is analyzed by formula derivation.Then,the above-mentioned derivation and analysis of the frequency splitting phenomenon of the resonant wireless power transfer system are verified by simulation.In order to solve the impedance mismatch problem caused by the detuning of the WPT system,the equivalent capacitance adjustment circuit and the corresponding control method are adopted.According to the phase difference and the relationship between the rising edge of the voltage signal and the rising edge of the current signal,the current working state of the WPT system is judged,and the impedance of the transmitting end is adjusted by adjusting the time of the equivalent capacitor circuit to the transmitting end of the WPT system,thereby restoring the WPT system.The Simulink model is established and the effectiveness of the equivalent capacitance circuit and control algorithm used in this thesis is verified.Then,a wireless power transfer system experimental platform is established to verify the effectiveness of the equivalent capacitance circuit and the control algorithm.The experimental results show that the method used in this thesis can improve the transfer efficiency and output power of WPT system.