Accurate Maximum Power Tracking of Wireless Power Transfer System Based on Simulated Annealing Algorithm

Wireless power transfer (WPT) technology has become a popular solution to battery charging of mobile equipment. However, the variation of the load power will affect the transmission capacity of the system, which might make the electrical load cannot gain the required rated power and function improperly. Based on the analysis of power transmission characteristic and resonance state of WPT system, this paper adopts the simulated annealing (SA) method to track the maximum power point (MPP) of WPT in bifurcation state. The power tracking effectiveness of the proposed SA method is compared with that of the traditional maximum power point tracking method in WPT system based on perturbation and observation. The SA method performances under different parameters are assessed with consideration of the number of iterations needed for convergence and the convergence probability. Experimental validation of the maximum power tracking of WPT based on SA method is presented under different load conditions. Experimental results verify that the proposed SA method realizes the maximum power tracking when the WPT system works in the power bifurcation area, thus making full use of the inverter's VA capacity and approaching a unity power factor.