Thermal and efficiency analysis of five-level multi-level clamped multilevel converter considering grid codes

Abstract

In this paper a five-level Multi-Clamped Multilevel Converter (5L-MLC2) topology is analyzed based on a typical grid integration application for renewable energy system. The loss and thermal distribution of the power devices in different switching legs are investigated and illustrated under rated condition. Afterwards, a loss and efficiency evaluation method is proposed and applied which take into account various injected reactive power ranges regulated by the grid codes. It is concluded that the loss and thermal distribution of 5L-MLC2 multilevel topology is unequal between the clamping switching legs and the main switching legs, it also shows a good and consistent efficiency characteristic under different output power ranges when complying with the grid codes.