Variability Analysis of Efficiency and Output Power of an Inductive Power Transfer Link

Abstract

The wireless power transfer (WPT) technique plays an important role in powering remote devices. The power delivered to the load (PDL) and power transfer efficiency (PTE) are both obtained by knowing the parameters of the WPT system. The knowledge of such parameters and its variability can aid the designer to establish the most important parameters for maximizing the PDL or PTE. This paper presents a variability analysis of PDL and PTE when the WPT parameters change their values. Each parameter can be measured with an associated variability range. The variations in the PDL and PTE functions are computed by using this range of variability of the input parameters. The sensitivities of PDL and PTE with respect to each parameter are also identified with the presented analysis. Experimental measurements were taken on an inductive link, which was specially designed for a recharging battery system of a wireless sensor node with a 5-mm gap between the transmitting and receiving coils. The results pointed out that only small ranges on the input rated values can be tolerated to avoid significant distortions on the output distribution and thus the deviation of the optimal operation point.