Efficient Magnetic Resonance Wireless Power Transfer Systems

This thesis aims to improve the performance of magnetic resonance wireless power transfer systems. Different factors have different effects on the performance and the efficiency of the maximum transfer of power in the system. These factors are: the resonance frequency; the quality factor of the resonators; the value and shape of the coils; the mutual inductance, including the distance between the coils; and the load. These systems have four potential types of connection in the transmitter and receiver. These types are Serial to Serial (SS), Serial to Parallel (SP), Parallel to Serial (PS) and Parallel to Parallel (PP). Each type has different applications because it has a different performance from the others. Magnetic resonance wireless power systems in some applications consist of one transmitter and one receiver, while in other applications there is a demand to transfer the power to more than one receiver simultaneously. Hence the importance of studying multiple receiver systems arises. The serial to serial type connection was studied along with the effects of all the other factors on the efficiency, including the existence of multiple receivers. The symmetric capacitance tuning method was presented as a solution to the frequency splitting problem that usually appears in SS wireless power transfer systems with a small gap between the two resonators. Compared to other existing methods, this method provides advantages of high efficiency and keeps the frequency within the chosen Industrial Scientific Medical (ISM) band. The impact of the connection type on the efficiency of wireless power transfer systems and the effect of the load impedance on each type was studied. Finally, an algorithm for intelligent management and control of received wireless power was offered to run a load that requires more than the received power.