Wireless Power Transfer System of AUV Based on Improved Coil Structure With Stable Output Power and Efficiency

Based on the principle of magnetic coupling resonance, a wireless power transfer (WPT) system based on a new coupling coil structure is proposed for wireless charging of autonomous underwater vehicle (AUV). Firstly, a magnetic coupling device with small size and light weight at the receiving end that can adapt to the special arc shape of AUV is proposed, which can improve the coupling between the transmitter and the receiver. Based on the finite element simulation software, the proposed coil structure is verified, and it is learned that the magnetic coupling device has good magnetic field constraint ability and coupling ability with a coupling coefficient of up to 0.51; then, the coupling topology is analyzed to show that the equivalent resistance of the coil will increase in seawater media; finally, an experimental system is set up to verify the scheme. The test results show that the system maintains an output voltage of 50V in the inverter, which can realize constant normal charging, and the maximum charging power of the system is 170W, and the corresponding efficiency is 92%. When there is a small angle shift at the receiving end, the transmission efficiency of the system is always above 90%, and the fluctuation rate does not exceed 2.5%.