Dielectric response and tunability of a dielectric-paraelectric composite
A theoretical study was carried out to determine the dielectric response and tunability of a composite consisting of a linear, low-loss dielectric matrix with uniformly sized, randomly distributed paraelectric Ba0.60Sr0.40TiO3 (BST 60/40) particles as functions of the volume fraction and size of the particles. The field dependence of the polarization and the dielectric response of the inclusions are specified through a nonlinear thermodynamic model and then incorporated into a two-dimensional finite element analysis. Near the percolation threshold for BST particles (∼27% to 45% depending on the particle size), high dielectric tunabilities with a lower effective permittivity than monolithic BST can be realized.
According to the actual demand of hybrid EMU, this paper introduces the characteristics of lithium titanate battery, circuit topology, and working principles of Bi-DC/DC converter. Taking into account the different operating conditions, corresponding control strategies are proposed. A simulation model is established using MATLAB/Simulink to verify the feasibility of control strategies. Finally, a full power test of battery energy storage system was done with the experimental platform.