[Objective]　To　address　the　issue　that　traditional　sensorless　algorithms　can　only　observe　electrical　angles　and　thus　cannot　be　applied　to　servo　positioning,　this　paper　proposes　an　8-pole,　9-slot　interior　permanent　magnet　synchronous　motor　with　an　asymmetric　rotor.　The　asymmetric　inductance　characteristics　of　the　rotor　are　utilized　to　observe　its　mechanical　angle.　[Methods]　By　introducing　magnetic　barriers　and　magnetic　bridges　with　different　parameters　under　different　pole　pairs　of　the　rotor,　the　magnetic　resistance　of　the　main　and　leakage　magnetic　circuits　between　the　stator　and　rotor　was　altered,　leading　to　periodic　variations　in　the　inductance　waveforms　that　were　directly　related　to　the　rotor＇s　mechanical　angle.　Based　on　the　analysis　of　the　magnetic　circuit,　a　correction　coefficient　that　considered　the　asymmetry　of　the　rotor　was　introduced　to　modify　the　inductance　calculation　method　using　the　winding　function　method.　[Results]　The　results　indicated　that　increasing　the　width　of　the　magnetic　barrier　reduced　the　inductance,　while　increasing　the　height　of　the　magnetic　bridge　increased　the　inductance.　Compared　to　finite　element　simulation　results,　the　average　percentage　error　was　approximately　1.　59%　.　[Conclusion]　The　calculation　and　simulation　results　validate　the　feasibility　of　the　proposed　asymmetric　rotor　topology　for　identifying　the　mechanical　angle　in　sensorless　algorithm.　©　Editorial　Office　of　Electric　Machines　&　Control　Application.