Thermal Modelling of Resonant Capacitor Boards for Inductive Power Transfer Systems

Resonant capacitor boards are used in compensation networks for inductive power transfer (IPT) systems. IPT systems typically use class 1 multilayer ceramic capacitors (MLCC) due to their high stability and relatively low losses. However, the losses of class 1 MLCCs are still a concern at high power levels and limit the power density of IPT systems due to thermal constraints. This paper characterizes the losses of a commercially available class 1 MLCC (TDK C0G) using calorimetric methods and predicts the temperature rise of resonant capacitor boards using computational fluid dynamics (CFD) simulations. The losses of the C0G capacitors used in the resonant capacitor boards were measured to be almost constant over a 60 °C temperature range. Steady-state simulations matched within 10.5%, and transient results were within 16.3%.