Simulation Circuit Model and System Design for Wireless Power Transfer System with an Intermediate Coil

In this paper, a simulation circuit model aiming at the wireless power transfer system with an intermediate coil is studied. The model is derived from the fundamental equations, which are commonly applied in the analysis and design of WPT systems, with less calculation and no extra assumptions. To guarantee the accuracy of analysis, harmonic components can be taken into consideration as well based on the given model. The proposed circuit model can reflect system characteristics in a precise way and an intuitive display of the results can be obtained directly with the help of a circuit simulation software tool. To make sure that the efficiency of the intermediate system is superior to non-intermediate systems, the optimum parameters are researched and a design principle is put forward as well. In addition, the influences of the intermediate coil position on system efficiency and harmonic current are also discussed. Moreover, because of the flexibility and precision, the transmitter (Tx) coil and the receiver (Rx) coil are designed based on printed spiral coils (PSCs) to reduce the size and weight of the prototype.