Application of modal analysis methods to the design of wireless power transfer systems

Wireless recharge of electric vehicles is an important field of research. Design of inductive power transfer systems involves the optimization of resonant coils coupled through mutually induced magnetic fields. Currently there is a big interest concerning both on optimization methods and on the research of innovative topologies able to maximize both power transfer and efficiency. In this work, authors proposed an innovative approach: resonant electric systems can be modelled as equivalent lumped mechanical models that can be optimized adopting conventional methods of modal analysis that are currently used to study mechanical vibrating systems. In particular, one of the main advantage of the proposed approach is the possibility of an intuitive physical interpretation of system behaviour. Proposed approach is applied to the study of some known Inductive Power Transfer topologies such as the series–series and the LCC ones. Application of the proposed bond-graph analogy with equivalent mechanical systems is used to propose some simple and effective design criteria for the optimal tuning of the over-cited coil topologies. Proposed methodologies are verified on benchmark test cases comparing obtained results respect to most recent conventional design methods proposed in literature.