The　load　capacity　of　five　phase　permanent　magnet　synchronous　motor　(PMSM)　with　third　harmonic　back　electromotive　force　(EMF)　can　be　further　improved　by　injecting　third　harmonic　current.　The　accurate　initial　position　of　the　rotor　directly　determines　the　starting　performance　of　the　motor.　An　initial　rotor　position　estimation　method　based　on　pulsed　voltage　injection　was　proposed　for　five-phase　PMSMs　with　high　proportion　of　third　harmonic　back　EMF.　Based　on　the　fundamental　wave　plane　mathematical　model　in　the　two　-　phase　static　coordinate　system,　the　rotor　position　estimation　formula　was　derived.　The　optimal　voltage　vector　that　should　be　injected　when　the　rotor　was　in　different　position　was　analyzed.　The　voltage　vector　was　selected　according　to　the　rotor　position　Angle　estimated　preliminarily　in　order　to　improve　estimation　accuracy.　Based　on　winding　function　method,　the　relationship　between　armature　magnetomotive　force　and　fundamental　and　third　harmonic　currents　were　analyzed.　In　this　paper,　two　voltage　vectors　in　opposite　directions　were　applied　to　the　motor　in　the　third　harmonic　plane,　and　the　polarity　of　rotor　was　judged　according　to　the　amplitude　of　the　third　harmonic　plane　current.　Experimental　results　verify　the　effectiveness　of　the　proposed　rotor　position　estimation　algorithm,　and　the　maximum　estimation　error　is　±5　degrees.　©　2022　Chin.　Soc.　for　Elec.　Eng.