Research On Starting Performance Of Line-start PMSM

Line-start PMSM promotion and application in the industrial field increasinglyattracted attention because of its power factor, efficiency above asynchronous motor of thesame power, but also has the advantages of asynchronous start capability. Line-startPMSM has many advantages compared to the same three-phase asynchronous motors, butat the same time there are many design problems. Line-start PMSM need to implement twofunctions: the asynchronous starting capability and the ability to maintain synchronousspeed running, so the rotor must be designed into the complex structure that coexist startwinding and permanent magnet, the rotor space competition is exist, especially the highpower density of the small motor, the rotor design is much more difficult. Since thepresence of the permanent magnet, resulting in an average of T-s curve at low speed to alower concave point, on the one hand, in order to ensure the smooth start of the motor, themotor could not like ordinary asynchronous motor voltage starting to limit the startingcurrent, high starting current need to rely on the optimization of the design of the rotorgroove to suppress, on the other hand, in order to improve the minimum torque and toreduce the amount of permanent magnets, the need to increase the stator winding turns,which makes the increase in manufacturing costs and working hours. At the same time, therotor magnetic circuit structure is complex, the local saturation magnetic circuit difficult toaccurately calculate the various parameters and determination, starting performance designis difficult.In this paper, a1.5kW-2pole line-start PMSM starting process has been tested, getthe start-up process of the prototype T-n curve, with multiple prototype locked-rotor test,measured the motor’s locked-rotor torque and locked-rotor current, comparative test data,summed up a set of finite element-based line-start PMSM starting performance simulationmethod. Second, line-start PMSM rotor slotted study focuses on the most significant skineffect convex slot, summarizes the design rules to improve the quality factor of the groovestarter. Based on the above studies, one with a higher starting quality factor, taking into account the pull-in performance18.5kW-4pole line-start PMSM, to meet the requirementsof the performance indicators.The results of this study has some theoretical significance and practical value,line-start PMSM starting performance related research work will provide experience forthe follow-up to improve.