Reduction of electrical stresses in grid micro inverter through semiconductor switches

Abstract

Micro inverters are power electronics devices integrated close to photovoltaic (PV) panels. PVs produced today could make 92% of its rated power. With the passage of time, the reliability and performance of micro inverter needs to be redesigned to operate under harsh temperature conditions. This paper presents the distribution of electrical and thermal stresses that occur in semiconductor devices of micro inverters. H5 micro inverter topology is simulated and analyzed as a benchmark of losses in devices of PVs. The performance of micro inverter is evaluated on the basis of conduction and switching losses in basic and distributed micro inverters using simulation tool PSIM. H5 inverter single switch conduction losses came out to be in the range of 6 W while the switching losses were about 0.12 W. Net conduction losses of the inverter were 24.2 W while the switching losses were 0.483 W. For modified inverter as well as auxiliary, single switch had conduction losses in the range of 1.64 W while the total conduction losses for individual switching segment were 13.22 W which are almost half of H5 losses. Results revealed that it has a significant impact on the micro inverter which is replaced with distributed components in this design and has a remarkable improvement. The conduction losses are reduced to 73% and that of switching losses are reduced to 58.4%; leading to major contribution in designing cost effective and safe applications for micro inverters.