**5. Discussion**

The bidirectional AC/DC converter topologies that are employed for V2G and V2H technologies and their features, advantages, and disadvantages are given in Table 2. In general, full-bridge topology is preferred in AC/DC conversion. As the power of the system increases, the number of the semiconductor switches that are employed in the switching process increases also, which, in return, increases the total harmonic distortion (THD) of the system while decreasing its efficiency. The output voltage of the converter varies depending on the battery voltage level or DC bus voltage (G2V or H2V). LC or LCL filters are preferred for connection to the grid in the V2G direction. These filters reduce ripples in the current and voltage.


**Table 2.** Comparison of bi-directional AC/DC inverter topologies for V2G applications in the literature.

The bidirectional DC/DC converter topologies used for V2G and V2H technologies and their properties, advantages, and disadvantages are given in Table 3. When the studies given in Table 3 are considered, for the increase of the voltage level for V2G or V2H transfer, or for the reduction of the voltage level for G2V transfer, the bidirectional buck–boost inverter is preferred. In the comparison table, the system feedback of the closed-cycle control system is employed with a current-controlled setting, voltage-controlled setting, or both together. As the battery voltage level increases, high-frequency switching is needed to control the system, and the efficiency of the system reduces. As the magnetic isolation between the inverter and the converter reduces the current and voltage ripples that are caused by the high-switching frequency, it increases the whole system efficiency.


**Table 3.** Comparison of bi-directional DC/DC converter topologies for V2G applications in the literature.
