A new design methodology for a 1 meter distance, 6.78 MHz wireless power supply system for telemetries

In this paper a new large distance, 6.78 MHz, fixed frequency, 50 W output, wireless power transfer system design methodology for telemetries has been proposed. Receiver side tuning topology is selected in the first step of the design methodology. Then, a nominal coupling coefficient between the transmitter and the receiver coil has been calculated using given distance and coil diameters. Feasible ranges of the transmitter and the receiver coil inductances are identified in the following step of the design methodology that satisfy given voltage and current limits. In the feasible design space concept, multiple transmitter and receiver coil geometries are found that result in maximum power transfer efficiency. Then, the control stability, copper weight, volt-amp ratings of the coils are calculated and their contour plots are plotted using the coil geometries. The contour plots shows the trade-offs between the system performance and the coil geometry selection. A new variable K is defined in order to find an optimal coil geometry. Using the variable K, the geometries of the transmitter and the receiver are able to be determined. The proposed design methodology is evaluated using an example wireless power transfer system design for an on-line condition monitoring system for a catenary. The efficiency and loss distribution of the designed wireless power system is evaluated by comparison of the theoretical, FEA, and circuit simulation results.