When developing three phase motor drives, the best way to validate the desiredfunctionality is to connect the inverter to an actual electrical motor. However, when developingfunctions which are not directly involved in controlling the motor, it could bemore efficient to use a real-time software model of the motor. In this master thesis, the developmentand implementation of a software model of a permanent magnet synchronousmotor (PMSM) is presented. This model was based on general dynamic equations forPMSM in a rotating reference frame (dq-frame). The model was simulated and convertedto C code using model based software development in Mathworks Simulink. To providemore realistic performance of the model, a finite element analysis (FEA) was done of anactual PMSM using the software tool FEMM. This analysis resulted in data describingthe relation between flux linkage and current which, when added into to software model,limits the produced torque due to magnetic saturation. Both the FEMM model and thefinal software model was compared to a corresponding actual motor for validation andperformance testing. All this resulted in a fully functional software model which was executableon the inverter. In the comparison of FEMM model to the real motor, a deviationin produced torque was discovered. This led to the conclusion that the model needed to beimproved to perform more alike the real motor. However, for this application the modelwas considered good enough to be used in future software development projects. / N¨ar kontrollsystem till trefasmotorer utvecklas s°a ¨ar det mest vanliga och troligendet b¨asta s¨attet f¨or funktionsvalidering att k¨ora drivenheten kopplad mot en riktig elektriskmotor. D¨aremot, om funktioner som ej ¨ar direkt kopplade till sj¨alva drivningen av motornutvecklas, s°a kan det vara mer effektivt att ist¨allet anv¨anda en mjukvarumodell. I det h¨arexamensarbetet s°a presenteras en mjukvarumodell av en permanentmagnetiserad synkronmotor(PMSM). Modellen baserades p°a de generella ekvationerna f¨or PMSM och simuleradessamt kodgenererades i Mathworks verktyg Simulink. F¨or att g¨ora modellen mer realistisks°a kompletterades den med data som beskriver relationen mellan det l¨ankade fl¨odetoch str¨om f¨or att ¨aven ta h¨ansyn till magnetisk m¨attnad. Den informationen simuleradesfram i verktyget FEMMgenom fl¨odesber¨akningar p°a en specifik motor typ. Samma motortyp har ocks°a j¨amf¨orts med den slutgiltiga mjukvarumodellen med avseende p°a utvecklatvridmoment vilket resulterade i n°agot st¨orre skillnader ¨an f¨orv¨antat. Slutsatsen blevs°aledes att modellen beh¨over f¨orb¨attras f¨or att p°a ett b¨attre s¨att st¨amma ¨overens med verklighetenmen att den fungerar tillr¨ackligt bra f¨or den ¨amnade applikationen.