Multivariable Automatic Compensation Method for Inductive Power Transfer System

The wireless power transfer can be useful in applications where the use of cables for powering remote devices are not suitable or even feasible. However, the transferred power is highly dependent on the relative position between the transmitter and receiver coils as well as other circuit parameters. The use of adaptive matching network in wireless power transfer system allows to track the maximum power transferred to the load while changing the magnetic coupling between the coils. By controlling both, the excitation frequency and matching capacitor at the primary side of the inductive link, the output power can be hold approximately constant over a large range of magnetic coupling coefficient. This paper presents an automatic compensation method for an inductive power transfer system. The proposed method monitors the magnitude and phase of the input current of the inductive link. Thus, the data is processed by a fuzzy logic controller actuating on the working frequency and on the matching capacitor in order to maximize the power transferred to the load. The proposed method can tolerate the movement of remote devices while charging processes.