3-D Embedded Receiving Coil Positioning Based on Decoupled Transformer for Wireless Sensor Power Supply System

Embedded sensors in structural health monitoring systems can be powered by wireless power transfer technology. However, misalignment between the transmitter and receiver is unavoidable, resulting in system efficiency and power decreases. To address this challenge, a 3-D positioning method for the embedded receiving coil based on a decoupled transformer is proposed. The decoupled transformer consists of two helical coils and one planar coil. These three coils are orthogonal to each other and decoupled magnetically. Coupling occurs only between the decoupled transformer and the receiving coil. This method requires neither auxiliary sources nor communication equipment, and it does not involve complex control. Experimental results show that when the transmission distance ranges from 50 to 80 mm, 93% of the positioning errors are within 10 mm in a 140 mm × 140 mm area. It is proved that the proposed method achieves a high accuracy.