Performance Comparison of PV Inverter Systems Considering System Voltage Ratings and Installation Sites

Currently, string photovoltaic (PV) inverters with wide DC and AC operating voltage ranges are available on the market, which can be employed for interfacing either 1000-V or 1500-V PV strings with different AC grid voltage levels (e.g., 400 V or 690 V). The selection of both the DC- and AC-side voltage levels should be carefully considered during the design phase. In this context, this paper compares the performance of PV systems using centralized string inverter solutions. The comparison is carried out by evaluating the power losses on each component (e.g., DC wire, inverter, AC filter, and transformer) of a 1.8-MW PV system considering different system voltage ratings and installation sites (mission profiles in Denmark and Sacramento, California). The evaluation results reveal that the impact of system voltage ratings on the energy yield of the PV system varies with mission profiles. Higher DC and AC voltage ratings can contribute to considerable energy loss reduction in both cases. However, in the cold climate, e.g., Denmark, the energy yield is more sensitive to the DC-bus voltage range, where the 1500-V PV system tied to a lower AC grid voltage (e.g., 400 V) can achieve higher energy yield.