Optimization algorithm and practical implementation for 2-coil wireless power transfer systems

Wireless power transfer based on inductive coupling techniques has attracted a lot of research interest in recent years. It can be potentially applied in many industrial sections. However, the harsh outdoor industrial environment could induce circuit parameter drift. Only small drift may result in huge performance drop, as the circuits are very sensitive to the parameter changes. In order to address the problem, an optimization method to compensate for the effect of drifting parameters and track the maximum performance is introduced in this paper. A switch network which is able to dynamically change the inductance of the Tx coil is designed. When the parameter drift occurs, the tuning algorithm is able to adjust both the exciting frequency and the Tx coil inductance. By measuring the input power only, the best working point can be found out without requiring any measurement on the Rx side. Therefore, the algorithm can be implemented in the controller located on the Tx side without coordination and communication between both sides. In order to verify the effectiveness of the proposed method, a test rig is setup and practical experiments are conducted. The experimental results are also presented in the paper.