Analysis of Inductive Coupling Wireless Power Transfer Systems

Abstract: Inductive coupling wireless power transfer (WPT) technology is gaining increasing popularity in recent years, especially in the field of wireless charging of portable devices. Although the principles behind WPT systems can be explained using well known results from electromagnetic theory, many questions remain regarding the behavior of such systems. This thesis focuses on identifying and analyzing the most important parameters of such system, with emphasis on the coupling factor. Algorithms to calculate the coupling factor and other parameters based on mathematical models of physical phenomena are developed and presented. This algorithm development is also called the analytical approach. For the coupling factor part, a commercial electromagnetic simulation software (Ansys Maxwell) was selected to validate the results obtained from the corresponding algorithm and also evaluate the performance of general-purpose simulators suitable for use in this field. For other WPT system parameters, the algorithm was compared to the results from LTspice. The results obtained from the developed algorithms and simulations are compared to measurement results collected from real transmitter and receiver coils. The results show that both the analytical and simulation approaches can provide estimated parameter values of interest that are close to the empirical values, with percentage error being in the low single digits in most scenarios. However, the developed algorithms are more specialized, and hence easy to implement and computationally more efficient. Consequently, they can be used to generate larger amounts of data for detailed analysis and characterization of WPT systems with relative ease.