This feature is available as a subnode to the Ampère’s Law, domain Coil, Faraday’s Law, Magnetic Flux Conservation, Magnet, Passive Conductor and Multiphase Winding features. This feature is used to calculate the copper loss due to the resistive heating or the iron loss due to the Hysteresis, eddy current and other effects. The feature is available with both Time Dependent and Frequency Domain studies. For Time Dependent studies, the loss calculation has to be used in combination with the Time to Frequency Losses study step. The Time to Frequency Losses is typically added after a Time Dependent study. Note that the Loss Calculation subnode needs to be added before the Time Dependent study is computed.

Select a model to compute the cycle averaged loss density Q (W/m3). The default loss model is computed directly from the resistive heating. If the Loss Calculation subnode is added to specific features and the Constitutive Relation B-H is set to appropriate relations, additional empirical models such as the Steinmetz and Bertotti models are available. The specific features include the Ampère’s Law, the Faraday’s Law and the Magnetic Flux Conservation but not the Coil. The appropriate relations include the B-H curve, the Effective B-H curve and the Hysteresis Jiles-Atherton model. The expressions of the loss density Q for different loss models are introduced as follows.

where Te, T, J, and E are the end time, electrical period (1/f), current density and electric field, respectively.

where f and B are the frequency and magnetic flux density, respectively; kh, α, and β are coefficients.

where σ is the bulk conductivity of the laminated material; G is a constant with a value of 0.1356; S denotes the typical magnetic circuit section area; V0 is the excess losses fitting coefficient; and kc is the classical losses term coefficient. kc can be computed from the lamina thickness d with the relation kc=π2d2/6 or be defined by the user. Note that the Bertotti model uses the material properties such as the bulk conductivity set in the interface, instead of the material data from the Material node.

This is an advanced setting where the loss power density as a function of the frequency (freq) and magnetic flux density (normfftB) is defined by the user.