A simplified control scheme for electric vehicle-power grid circuit with DC distribution and battery storage systems

Abstract

The direct current (DC) system is becoming the major trend for future internal power grid of electric vehicles (EVs). Since DC power grid system has a different nature to conventional alternating current (AC) grid system, appropriate design of the controller for EV-grid circuit is mandatory. In this paper, an EV employing a pure DC grid circuit with battery storage system (BSS) is considered as a study case. To enable a more efficient use of BSS, a flyback DC-DC converter for batteries charger/or discharger strategy is selected, which satisfies the power flows requirements. The dynamic and control performances of the combined system, i.e. ‘BSS-flyback DC-DC converter connected to a DC motor’, is investigated in terms of voltage/current signal fluctuations. The small-signal based control method is used, which limits the small-signal variations to about zero. To verify the effectiveness of the control strategy, several simulations are done using Matlab. The simulation results illustrate the performances obtained.