The　three-level　multi-phase　drive　system　combines　the　advantages　of　multi-phase　motors　and　three-level　inverters.　However,　midpoint　voltage　imbalance　and　excessive　zero-sequence　current　exist.　Midpoint　voltage　imbalance　can　lead　to　output　voltage　distortion,　while　excessive　zero-sequence　current　can　cause　distortion　of　the　stator　current　and　increased　losses.　Direct　torque　control　(DTC)　requires　minimal　dependence　on　motor　parameters,　with　a　simple　algorithm　and　strong　adaptability　to　load　changes.　However,　research　based　on　DTC　theory　is　still　relatively　rare.　The　symmetrical　six-phase　permanent　magnet　synchronous　motor　(PMSM)　has　high　efficiency,　a　fast　response　rate　among　multi-phase　motors,　and　superior　fault　tolerance.　Therefore,　this　paper　proposes　a　DTC　strategy　for　a　symmetrical　six-phase　PMSM　powered　by　a　T-type　three-level　inverter　to　balance　midpoint　voltage　and　suppress　zero-sequence　current.　Firstly,　by　using　a　spatial　vector　projection　method　to　remove　the　redundant　switching　states　in　the　switching　state,　the　switching　states　are　reduced　from　729　to　189.　Secondly,　based　on　the　three-phase　PMSM-DTC　structure　powered　by　the　two-level　inverter,　the　scheme　synthesizes　four　voltage　vectors　to　meet　the　control　requirements　on　the　six-phase　axis　using　the　simplified　switching　state.　In　addition,　by　combining　flux　linkage　and　torque　hysteresis　comparator　with　simple　sector　division,　the　axis　of　the　optimal　voltage　vector　is　determined,　and　the　midpoint　voltage　and　zero-sequence　current　control　plane　are　constructed.　The　sector　where　the　system　is　located　in　the　control　plane　is　judged.　According　to　the　polarity　of　the　winding　phase　current　iy　of　the　optimal　voltage　vector,　the　optimal　voltage　vector　selection　is　realized,　and　the　optimal　switch　vector　table　of　DTC　is　further　constructed.　Steady-state　comparative　experiments　are　conducted.　Compared　to　the　traditional　approach,　the　proposed　method　maintains　a　balanced　midpoint　voltage,　effectively　suppresses　zero-sequence　current　to　approximately　0　A,　and　significantly　sinusoidalize　phase　current.　Steady-state　running　experiments　are　conducted　at　different　speeds　and　loads　to　investigate　the　steady-state　performance　of　the　motor.　The　results　show　that　zero-sequence　current　is　effectively　suppressed　to　approximately　0　A,　and　the　midpoint　voltage　remains　balanced.　Speed　step　and　sudden　load　change　experiments　are　performed　to　validate　the　dynamic　performance　of　the　motor.　The　results　demonstrate　that　the　zero-sequence　current　can　still　be　well　controlled　around　0　A,　even　during　speed　steps　and　sudden　load　changes.　Although　the　midpoint　voltage　may　fluctuate　slightly,　it　can　be　quickly　adjusted　to　a　balanced　state.　The　following　conclusions　can　be　drawn.　This　paper　proposes　a　DTC　strategy　for　a　symmetrical　six-phase　PMSM　powered　by　a　T-type　three-level　inverter,　addressing　the　control　of　|ψs|　and　Te,　midpoint　voltage　balance,　and　zero-sequence　current　suppression.　©　2024　China　Machine　Press.　All　rights　reserved.