**5. Discussion**

From both simulation an experimental results, it was shown that current and voltage stress was kept in reasonable levels and only switches were affected by a voltage transitory. The last, is also present in boost-HB topologies, however over-current peaks are not present in CZSI as can be seen in Figures 13 and 14, which sugges<sup>t</sup> a lower current stress in semiconductor devices. In addition the shoot through operation gives more time to react to faults related to gate signals in switches: if the gate signals are lost due to external factor like irradiated noise from MF link or processor damage, the switches will be protected by the Z-source by limiting current until a protection flag is enabled. On the other hand, boost-HB topologies will just be damaged in case of losing gate signal, and thus suggesting that the CZSI enhance the reliability of the system.

For unbalanced power conditions, it can be seen that voltage between all PV arrays terminals remains similar for all the ports. However current supplied to each CZSI modules is different and is a function of the power supplied by the corresponding PV array. The voltage remains similar for all CZSI modules, as shown in simulation and experimental results. The current is the parameter that changes for the primary modules and thus the one that validates the transfer of different power levels in primary ports as shown in Figures 10 and 13.

Despite the unbalanced power levels of the primary modules, the voltage is the same in secondary ports, but also the current is the same and thus the power on secondary side is balanced without additional actions, or modulation taken. The last is particularly useful for multilevel inverter applications where multiple isolated and balanced sources are required for proper operation. Topologies with galvanic isolation previously reported, usually implement multiple single-input single-output transformers in order to manipulate strings individually, this allows to follow MPP on each PV array and drive the transformer. However this produce different output on secondary side for each string and thus requires to be balanced by some added control strategy.
