ESR Modeling of Class II MLCC Large-Signal-Excitation Losses

Multilayer ceramic capacitors (MLCCs) with ferroelectric Class II dielectrics enable extremely high volumetric capacitance density, and are therefore preferred in high-power-density power conversion. These MLCCs, though, suffer from a nonlinear dielectric constant and substantial low-frequency, large-signal excitation losses. Previously, a Steinmetz-parameter-based loss model accurately described these large-signal losses in MLCCs, but a difficult peak-charge measurement was required. For magnetic materials, a Steinmetz-based model is translated to an operating-point-specific effective series resistance (ESR) model, which then allows for a low-complexity loss calculation. In this letter, we introduce and verify an ESR-based loss model for MLCCs, with the ESR derived from the MLCC Steinmetz parameters. Our modeling error is below 25% across all evaluated operating points, a major improvement over modeling with the small-signal ESR provided in the MLCC datasheet, which may result in a loss approximation error of up to 10×.