Flexible design method for multiple loads inductive power transfer system with equal power distribution

An inductive power transfer (IPT) system for powering multiple sensor nodes placed at various distances is proposed, in which the relay coil not only performs as a power relay to enhance the magnetic field along the power transfer route but also supplies energy to the local load. Based on Kirchhoff's law, the equivalent circuit model of the multi-load IPT system is established, and the relationship between power distribution and mutual inductance of adjacent coils is investigated. Aiming at practical applications, a flexible design method for the adjacent coil distance is proposed to adjust the mutual inductance and regulate the power distribution. Experimental results show that the equal power distribution is achieved for five loads across a transfer distance of 60.9 cm. Each load dissipates about 0.78 W with a power variation within 6.3%. The results indicate the feasibility of the proposed design method in the multiple-load wireless sensor network (WSN) applications.