MISO configuration efficiency in inductive power transmission for supplying wireless sensors

Abstract

Inductive power transmission depends on many parameters such as the distance and the alignment between the coils, the working frequency, the current excitation, the geometry and the property of the coils, etc. Exchanging power distance between coils in wireless power transmission using inductive link is generally low, it is shorter than the diameter of the sending coils. Consequently, increasing coil to coil distance causes a harm decrease of the transmitted power and the efficiency of the system. A major technical challenge affecting the use of this kind of power transmission is to find a way of sending energy to the target devices in an efficient and reliable manner taking into account this influencing effect. In this paper, we explored potential solutions to overcome this challenge by adopting a Multiple Input Single Output (MISO) coil system able to decrease the magnetic flux leakage and orientate the magnetic field to the receiving coil by powering the neighbor coils of the active ones in opposite direction. This technique can be implemented in many industrial applications such as supplying wireless sensors installed into a conveyor. Same parameters according the model of the coupled coils on SISO and MISO configurations are developed and simulations by finite element method are done. The investigation shows that the MISO orientated system is capable to transfer 42 mW over a 50 mm distance and reaching 30% efficiency.