Robust Control of Ultrasonic Power Transfer System Under Parameter Perturbation

Ultrasonic Power Transfer (UPT) technology has many advantages such as easy concentration of energy, no electromagnetic interference, and penetration of metal media, so it has great application prospects in wireless charging of underwater vehicles. The underwater vehicle during the charging process is affected by the complex marine environment, which will change the relative position, operating frequency and equivalent load of the UPT system, which in turn affects the stability, transmission power and efficiency of the system. Aiming at the above problems, this paper firstly uses the generalized state space averaging method (GSSA) to establish the state space model of the UPT system in the marine environment. Then, the uncertainty model of the system parameters is established on the basis of state space model considering the parameter perturbation of the operating frequency and equivalent load. A robust H_∞ controller based on M-Δ feedback control structure is designed. Finally, it is verified by the simulation. When the input current of the system changes or the output disturbance occurs, the robust controller can make the output current track the reference input quickly without overshoot, and has a good suppression effect on the influence of parameter perturbation.