Robust control of wireless power transfer system

In recent years, wireless power transfer systems have successfully been used in various industrial applications due to their contactless power transfer feature. However, these systems behave as higher order resonant networks and hence are highly sensitive to changes in system parameters. Traditional PID controllers often fail to maintain satisfactory power regulation in the presence of parametric uncertainties which include load and circuit parameter variations, variations in magnetic coupling between the primary and secondary coils. To overcome these problems, this paper designs a robust H
_∞
output feedback controller for a bi-directional inductive power transfer system. The control design is carried out following Ricatti approach. Simulations are conducted to verify the power regulation performance of the proposed controller and it is compared with a classical PID controller. The results show that the H
_∞
output feedback controller could successfully regulate the power in both directions in the presence of large uncertainties in various circuit parameters.