IGSE-Cx- A New normalized steinmetz model for class ii multilayer ceramic capacitors

Abstract

Ferroelectric Class II ceramic capacitors allow for highly compact converter realizations, but are showing relatively high losses for large-signal excitations which must be taken into account in the system dimensioning. Recent literature introduced the iGSE-CQ, a Steinmetz model based on the macroscopic capacitor Q-U hysteresis, allowing to accurately predict the losses of X7R capacitors. However, the model is specific for each single device, i.e., is insufficient to characterize losses in devices of the same series and manufacturer, which are employing the same dielectric material but with different voltage rating or nominal capacitance value. In this publication, based on basic physical properties we propose a new Steinmetz model, the iGSE-CX based on the relative dielectric material D-E hysteresis, which is applicable to all devices of a capacitor series. The iGSE-CX loss modeling technique is demonstrated for the TDK X7R, the TDK X7T, as well as the Knowles Syfer X7R series. Finally, the iGSE-CX is employed to estimate the large-signal losses of the capacitors of a three-phase inverter and shown to offer sufficient accuracy for a first power circuit design.