Considering　the　reliability　of　modular　multilevel　converter　(MMC)　closely　related　to　key　component　parameters,　a　novel　parameter　estimation　method　is　proposed　for　insulated　gate　bipolar　transistor　(IGBT)　of　submodule　(SM)　in　MMC.　The　relationship　between　the　switch　status　and　the　voltage　of　submodule　is　analyzed　and　the　model　of　the　bridge　arm　voltage　is　established.　Kalman　filtering　theory　is　introduced　against　the　measurement　noise　of　the　bridge　arm　data　from　sensors.　Under　the　linear　minimum　variance　criterion,　the　model　of　the　IGBT　parameter　monitoring　information　in　MMC　submodule　is　established　to　obtain　the　IGBT　parameters　from　each　submodule　in　the　bridge　arm.　The　substantial　reduction　in　the　number　of　voltage　sensors　improves　the　system　reliability　and　decreases　its　cost　and　complexity.　This　method　can　also　effectively　eliminate　the　influence　of　sensor　noise.　Finally,　the　effectiveness　of　the　proposed　technique　is　validated　via　a　PSCAD/EMTDC　simulation　analysis　of　MMC-HVDC.　©　Springer　Nature　Singapore　Pte　Ltd.　2020.