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.