Parameter-Independent Battery Control Based on Series and Parallel Impedance Emulation

Abstract

Appropriate voltage control is essential in order to extend the useful life of a battery. However, when universal chargers are used, the design of this control becomes more complicated, given the fact that the battery impedance value may vary considerably, depending not only on the operating point but also on the type, size, and aging level of the battery. This paper first shows how the voltage regulation can become extremely variable or even unstable when the controller is designed according to the proposals in the literature. We then go on to propose the emulation of a series and parallel impedance with the battery, which is easy to implement and achieves a control that is completely independent of the battery connected. The simulation results obtained for batteries with resistances ranging from 10 \text{m}\Omega to 1 \Omega , show the problems with existing controls and confirm that the proposed control response is similar for all the possible range of battery resistance.