Power Losses Evaluation for Modular Multilevel Converter with Junction Temperature Feedback

This paper evaluates the converter power losses of the modular multilevel converter based HVDC systems (MMC-HVDC). A junction temperature feedback method is proposed in order to estimate the power losses more accurately. Based on the data provided by the manufacture, the characteristic of semiconductor device is acquired. Both the switching and conduction losses are calculated with the real-time voltage and current waveforms, which are derived from the detailed PSCAD/EMTDC model. Thermal circuit model is applied to estimate the average junction temperatures of the semiconductors. The converter valve losses with different heat sink temperatures are also investigated. Power losses evaluation results demonstrate that MMC topology has the lower valve losses than the 2-level or 3-level VSC topologies.