Novel Parallel Serpentine Coils with High Lateral Misalignment Tolerance and Power Transfer Efficiency Optimization

Inductive wireless power transfer (WPT) systems are achieved by novel parallel serpentine coils. By considering the uniform magnetic field distribution generated by parallel serpentine coil, high lateral misalignment tolerance can be achieved by little mutual inductance variance. Furthermore, a method to improve the efficiency of WPT using serpentine coils is also presented in this paper. The measured efficiency is 49% when two coils are aligned, and still maintains 39% when 35 mm lateral misalignment occurs. Comparing with the conventional spiral coil, efficiency decay rate (EDR) suffers 57% degradation at lateral misalignment of 35 mm. The proposed coil improves lateral misalignment tolerance for only 20% EDR at the same condition.