Isolated　bidirectional　dc/dc　converters　(IBDDCs)　are　widely　used　in　the　renewable　energy　systems　such　as　solar　energy　and　wind　power　as　the　power　interfaces.　Dual　active　bridge　(DAB)　converters　show　many　advantages　compared　with　other　IBDDCs,　such　as　high　power　density　and　easy　in　control　implementation.　Nowadays,　many　advanced　controls　with　multiple　phase-shift　variables　such　as　triple　phase-shift　(TPS)　control　have　been　proposed　to　improve　the　efficiency　for　a　wider　output　power　range.　In　order　to　ensure　the　system　reliability,　the　fault　diagnosis　is　essential　to　identify　the　faulty　devices　quickly　and　avoid　the　system　collapse.　In　this　paper,　three　common　operation　modes　are　analyzed　and　an　open-circuit　diagnosis　strategy　is　proposed　for　DAB　converters　under　the　advanced　TPS　control.　Main　simulation　and　experimental　results　are　provided　to　validate　the　proposed　fault　diagnosis　method.　©　2019　IEEE.