Online voltage phase synchronization in receiving coils of multi-input wireless power transfer.

In multi-input wireless power transfer (WPT) systems, it is plagued to create a destructive interference between the multiple transmitters to result in a relatively low voltage delivered to the receiving coil and load, due to the phase differences of the received voltages from different transmitters. In this regard, it is essential to synchronize the phases of the received voltages of the receiving coil from different transmitters. However, the existing offline synchronization methodologies rely heavily on an analytical form solution of the received voltage in a receiver. In most engineering application scenarios, such close-form solution is almost impossible. Moreover, the close form solution, even if possible, will vary with the operating conditions and environments. To eliminate these deficiencies of existing synchronization methodologies, an online synchronization methodology is proposed for a multi-input WPT system. In the proposed methodology, the received voltages from different transmitters are determined from a series of online voltage samplings under different offset phases, and a synchronization strategy is then proposed and implemented. A multi-input WPT prototype is developed to test the feasibility of the proposed synchronization methodology. The experimental results have demonstrated that the received voltage is significantly enhanced by applying the proposed online phase synchronization methodology. [ABSTRACT FROM AUTHOR]