Wear-Out Analysis of a Grid-Forming Two-Phase Three-Wire Converter Under Unbalanced Load

The grid-forming converter that supplies voltage magnitude and frequency is a key element for isolated remote communities, and then wear-out analysis is an essential figure of merit. Therefore, this paper proposes the two-phase three-wire (2
$\Phi$
3 W) grid forming converter applied in a case study of isolated riverside communities in the Brazilian Amazon region. The proposed
xyn
-converter displaces the voltage line angle in 180
$^{\circ }$
, differing from
$\alpha \beta$n
-converter and
abn
-converter that displace voltage line angle in 90
$^{\circ }$
and 120
$^{\circ }$
respectively. First, the authors have also proposed a semiconductor current stress evaluation for 2
$\Phi$
3 W converters comparing the RMS current. Then, the lifetime evaluation of the three evaluated grid-forming converters is conducted. The results show that the converter operating in the
xyn
-converter presents the highest reliability among the three converters. Finally, the thermal stress analysis is validated by means of a 2
$\Phi$
3 W converter prototype with an open semiconductor module. For the evaluated converters, the
xyn
-converter has the least thermal stress for balanced and unbalanced load conditions and therefore the longest lifespan. The experimental validation shows that the average temperature of the
xyn
-converter is 19.4% and 23.3% lower than both the
abn
-converter and the
$\alpha \beta$n
-converter under balanced load conditions.