# Common-Ground Photovoltaic Inverters for Leakage Current Mitigation: Comparative Review
## 2 Classification of Common-Ground Converters
### Voltage-Source CG Converters (VSCG)  
#### 2.2.1 Bucking VSCG  
Figure 4 shows the converters that belong to this group. Table 5 summarizes the features and limitations of each converter. \begin{table}
\begin{tabular}{c c c c} \hline
**Converter** & **Features** & \multicolumn{2}{c}{**Limitations**} \\ \hline  & & & \(\bullet\) & High input capacitance is required for power decoupling. \\  & & & \(\bullet\) & High number of passive components are required \\ Refs. [36; 37] & \(\bullet\) & The input current is continuous. & \(\bullet\) & For practical implementation where there is a value for the element’s resistance, the gain in the positive half-cycle is different from it in the negative half-cycle. Thus, DC current injection is expected. \\ \hline  & & & \(\bullet\) & Its gain is varied according to the values of load power, switching frequency, and used inductance; Thus, for PV systems where the output power is varied with the environmental conditions, the gain is not constant. DC/DC boost converter may be needed for constant voltage gain, especially for grid integration. \\ Ref. [38] & \(\bullet\) & All the switches are unidirectional; thus, lower cost and high efficiency can be acquired. & \(\bullet\) & All the switches are unidirectional; thus, they can only be used at unity power factor. \\  & & & \(\bullet\) & The developed MPPT algorithm is complicated as it is highly dependent on the system parameters, which can be varied with time. \\  & & & \(\bullet\) & The input current is not continuous. This adds more complexity to MPPT operation. \\ \hline  & & & \(\bullet\) & It needs a high number of semiconductors; therefore, the efficiency will be low, and the cost increases. \\  & & & \(\bullet\) & The input current is discontinuous \\ Ref. [39] & \(\bullet\) & Low number of passive components is needed. & \(\bullet\) & High input capacitance should be used for power decoupling \\  & & & \(\bullet\) & DC current generation is expected as an unequal number of switches is conducting during \\  & & & & positive and negative half-cycles. \\ \hline  & & & \(\bullet\) & Using 2 magnetic components (one inductor and one coupled inductor) increases the cost and size and decreases the efficiency \\ Ref. [40] & \(\bullet\) & The input current is continuous. & \(\bullet\) & High capacitance value may be needed for power decoupling. \\  & & & \(\bullet\) & Special attention should be taken when dealing with the dead-time between the switch’s \\ Ref. [41] & \(\bullet\) & It uses the lowest number of switches; thus, low complexity can be acquired & \(\bullet\) & Operations to avoid high stresses on the switches. \\  & \(\bullet\) & The input current is continuous. & \(\bullet\) & High number of passive components is needed; this increases the cost and decreases the efficiency \\  & & & \(\bullet\) & High input inductance value should be used. \\ \hline \end{tabular}
\end{table} 
Table 4: Features and limitations of current-source CG converters. Figure 4: Voltage-source common-grounded (CSCG) converters (bucking type). (**a**) Converter presented in the work of [42; 43; 44], (**b**) converter presented in the work of [45], (**c**) converter presented in the work of [46], (**d**) converter presented in the work of [47], (**e**) converter presented in the work of [48], (**f**) converter presented in the work of [49], (**g**) converter presented in the work of [50], (**h**) converter presented in the work of [51], (**i**) converter presented in the work of [52], (**j**) converter presented in the work of [53].