In addition to the research on the magnetic design of the coils (link to other page), we are working on the design of resonant WPT circuits. For this purpose, the system path can be reduced to an equivalent circuit, which can be calculated with circuit analysis. The focus of this work is on the electrical system behavior, with particular interest in efficiency, losses, and current and voltage loading in the system.
The low magnetic coupling of the coils results in a high reactive power within the circuit, and due to the position dependence of the coupling, the inductances in the circuit are not constant. These variations must be covered or compensated by the power electronics.
Therefore, we investigate the frequency-dependent system behavior of resonant converter circuits and the influences of different compensation topologies on it and on different charging strategies (CV or CC). Furthermore, we are working on design methods for automated design and parameterization of power factor correction or circuit parameters for different interoperable requirements. Depending on the secondary side (nominal power, rectifier, compensation topology) and its positioning, the primary side power electronics must be able to serve a certain impedance space and be designed accordingly. Current and voltage limits of the power electronic components have to be taken into account. With the help of circuit analysis, transfer function and efficiency can be determined for different frequencies and coil combinations (and park positions), allowing different operating points to be calculated, compared and evaluated.