A New Approach for Optimizing a Bipolar Charge Transport Model for Dielectric Materials: Theoretical Framework

A bipolar charge transport model with two levels of traps (shallow and deep traps) is employed to describe and investigate the dynamic behavior of the space charge in low-density polyethylene (LDPE). This kind of model requires some initial experimental conditions alongside a set of parameters. An optimization method is used in order to provide the best precision for model parameters. Furthermore, the sensitivity of these parameters has been analyzed using an approach based on Sobol's method. In essence, this paper proposes a specific protocol that contributes to producing a global set of parameters able to provide the best approximate fit between experimental and simulated results. Net charge density is measured by the pulse electro-acoustic method (PEA) along with what is known as external charging current measurements. The simulated data are obtained by a bipolar charge transport model, which is developed for low-sensity polyethylene.