Investigation of DC Fast Charging Topologies for Electric Vehicle Charging Station (EVCS)

Implementation of a suitable DC-DC converter for charging the battery plays a crucial role in the pathway of electric vehicle (EV) production. The DC-DC converter should be designed in such a way to enhance the battery lifetime and battery performance. Thus, the DC-DC converter used for charging should be ripple free and highly efficient. The most commonly used classical converters for charging are Z-source converter (ZSC) and Quasi Z-source Converter (QZSC). In this, QZSC is preferred as it draws the continuous input current whereas the ZSC draws the discontinuous input current which increases the ripple content and in-turn reduces the performance of both the converter and battery. Hence, QZSC is mostly preferred for battery charging but it has the same duty ratio of the classical buck converter. Thus the paper examines the performance of all the three converters: classical buck converter, QZS buck converter and proposed switched capacitor QZSC (SC-QZSC). The performance parameters such as load voltage ripple (ΔV
₀
), load current ripple (ΔI
₀
) and inductor current ripple (ΔI
_L
) is evaluated and compared. From the analysis, SC-QZSC is chosen as it meets the charger requirement. The simulation studies are carried out in MATLAB/SIMULINK and the results are verified.