Wireless Power Transfer Optimization with a Minimalist Single-Capacitor Design for Battery Charging

Along with the emerging needs to either complement or replace the limitation of energy storage technologies in batteries in supplying power to mobile devices, including electric vehicles, Wireless Power Transfer (WPT) technologies are becoming the main focus to solve this problem. However, much research is still in progress in relation to how to achieve high power delivery from the transmitter to the receiver of the WPT circuit. Since most research that has been done tends to add components or circuits so that the system becomes more complex, this study proposes the optimization design of a single capacitor on the WPT transmitter side due to the fact that the presence of the rectifier circuits guarantees the existence of a capacitance characteristic on the receiver side. Using a full bridge rectifier to represent the WPT load, a mathematical model of the overall system is then built based on state space and transfer function methods. Then, a Genetic Algorithm (GA) is applied to the model to find the optimum solutions for achieving high power delivery. Here, the WPT power output to the load is chosen as the fitness function, while the constraints are the available capacitance and voltage source frequency values. A case study with MATLAB R2024b simulation shows that the proposed method successfully delivers the highest possible power transfer delivery, which is around 0.1 watts using a normalized AC voltage source amplitude of 1 volt. This power will increase if the voltage source amplitude is increased. In addition, the results of the GA sensitivity test ensure the consistency of the optimization results.