Control of DC–DC power converters in the presence of coil magnetic saturation

Engineers generally design control for power converters based on standard models that assume the involved passive components to be linear. In reality, the magnetic characteristics of these components are nonlinear (especially in the presence of large magnetic flux density in the ferromagnetic core). This nonlinearity, which is of the saturation type, is particularly pronounced in higher power coils. Therefore, a controller obtained from the standard models may not achieve the performance it is designed for under operational conditions where the nonlinearity of the components is not negligible. In this paper, the authors investigate the effect of coil magnetic saturation for certain converters is investigated. It is shown that the control performances actually deteriorate if such a feature is not accounted for in the converter modeling. A solution that explicitly accounts for the nonlinearity of coil characteristics is developed for two converters.