High frequency model of a shielded 4-wire energy cable

In adjustable speed drive (ASD) applications, most cables connecting the electronic voltage source to the AC-motor are multi-wire and shielded. The various inductive and capacitive effects are at the origin of high frequency phenomena that require models with distributed parameters as in transmission lines. From curves showing the evolution of the cable impedance with frequency, and under the assumption of choosing appropriate models, it is possible to calculate the values of the numerous parameters of the model from design tool software. This paper deals with the modelling of a shielded 4-wire energy cable, with the determination of the values of the parameters R, L, C and G of the energy cable, in order to obtain an equivalent electric model which is valid both in the time and frequency domains. The obtained results show that the proposed model reproduces the oscillations of current induced by the hard switchings of the power converter with a difference lower than 10% when compared to experimental measurements