Constrained use of modulated energy-storing processes with and without internal modulation in bond graphs

In many bond graph models, it is convenient, for simplicity reasons, to use internal and/or energy-pumping modulations (IM and EPM). However, the result is often physically absurd. Using cardiac models as motivating examples, the author shows that a particular class of IM and EPM, made of internally and externally modulated n-ports energy storing elements, may be modified to restore physical consistency