Modelling and control design of reconfigurable wireless power transfer system for transmission efficiency maximisation and output voltage regulation

In a wireless power transfer (WPT) system, higher transmission efficiency and regulated output/load voltage/power are two major design targets or criteria of interest. This study presents the modelling, control design and stability evaluation of a reconfigurable WPT (R-WPT) system which can achieve constant receiver/load's voltage/power and realises transmission efficiency maximisation under varying transmission distances (DIS) and misalignment (MIS) conditions in addition to varying load conditions. The controller is realised to adaptively switch between different sizes of drive loops and load loops. As a result, the loop-coil coupling factors are optimised to realise transmission efficiency maximisation. The small-signal modelling of the complete closed-loop control R-WPT system is derived to evaluate the system stability during different configurations and different DIS/MIS conditions. Detailed sets of experimental results are provided and discussed throughout the study to give insight on the system modelling, operation and performance.