Mission Profile based Reliability Analysis of a Medium Voltage Power Conversion Architecture for PMSG based Wind Energy Conversion System

The development of wide-bandgap (WBG) power semiconductor devices has opened up new areas of applications which were previously dominated by silicon based IGBTs. This paper presents one such application where a multi-megawatt permanent magnet synchronous generator based wind energy conversion system (PMSG-WECS) is used for medium voltage (MV) grid integration. The conversion of the low output voltage of the PMSG to medium voltage brings about a multitude of advantages including reduction in the cable diameter and consequently the cost and weight of the system. WBG devices enable the use of high frequency transformers which makes it possible to install the system on the tower of the wind turbine. With these kinds of installations, it becomes necessary to investigate the reliability of the system, since maintenance of the systems leads to additional incurred costs. This paper provides a mission-profile (i.e. wind speed and ambient temperature) based analysis, in order to determine the temperature rise in the devices and consequently, its effects on the lifetime of the devices. An analytical lifetime model has been used and the damage produced on the transistors has been quantified using Palgrem Miner rule. This analysis can be helpful in understanding the impacts of having a tower-top converter system on the overall cost.