Output power stabilisation of wireless power transfer system with multiple transmitters

Wireless power transfer via strongly coupled magnetic resonance is an effective and convenient technology to transfer energy. The output power splitting in close distances and monotonic decay of the output power in longer distances exist when it comes to single-transmitter case. For the sake of more stable output power in a broader space, the authors proposed a novel wireless power system with multiple transmitters. Further analysis of features of both single-transmitter and multiple-transmitter systems was presented with the adoption of MATLAB and High-Frequency Structure Simulator. The authors demonstrated the superiority of the multiple-transmitter system and then investigated the impact of transmitter spacing on output power. To stabilise the output power as much as possible, an optimisation strategy is designed by setting transmitter spacing as decision variables and the minimum power variance as the target. The measurement shows that for a load demand of 5 W, a stable area with a standard deviation of 0.32 can be achieved when transmitters are placed 0.33 m apart. Both theoretical and simulation results make it possible to power the movable devices more stably.