Wireless Power Transfer Control System and Magnetic Design

Abstract

In this thesis, the design and implementation of power converter and controller for wireless power transfer systems are studied. Transferring electricity without a direct use of conductors to transfer power from the source to the load has become a hot topic recently despite the existing limits on the level of transferred power, distance, and efficiency of the system. The newly commercially available fast high-power switches have enabled power electronics designers to address some of the limitations, as high frequency switching is one of the requirements for wireless power transfer. As the increase of switching frequency entails higher switching losses, soft switching methods are normally used to in transfer systems. A new control method is introduced that guarantees the soft switching with controllable active load power injection using only one feedback. In this control method, zero voltage switching is achieved using variable frequency control. Moreover, a systematic magnetic design process is introduced to effectively design the inductive power system. The implemented magnetic design is verified with accurate Maxwell simulation. Through first harmonic approximation, a converter design is developed for the IPT system. With many uncertainties in the design process, the experimental and simulation results are slightly different. In addition, a resonant wireless power transfer system is designed through optimized searching of the available options. The bottleneck for design is identified through comprehensive analytic and simulation analyses.