Performance analysis of various rotor topologies of surface PM synchronous motor

Vasilija Sarac

   Surface mounted permanent magnet synchronous motors can be found in several designs regarding configuration of magnets on the rotor. Finding the most optimal design in terms of the high efficiency and power factor, small cogging torque and material consumption along with good overloading capability could be a challenging task. This paper analyzes three different rotor designs of surface permanent magnet motors regarding their magnet shapes. All three motors have the same outer dimensions, output power, torque and the material properties. The comparison of all three models is performed and advantages and drawbacks of each model are pointed out. Four design variables are selected to be varied within prescribed limits for each motor model in order the best combination of number of conductors per slot, magnet thickness, the magnet length and shape to be fond, which result with the highest efficiency, small cogging torque and good overloading capability of the motor. The impact of each varied parameter on motor efficiency and cogging torque is presented. All three optimized model are compared and the most optimal model in terms of the above-mentioned characteristics is analyzed by Finite Element Method (FEM) and with the Simulink. The model in Simulink allows motor transient characteristics to be obtained. The performed analysis is useful for determining the most optimal and cost-effective solution among presented three types of surface mounted permanent magnet motors in terms of the high efficiency and power factor, small cogging torque and material consumption.

Keywords: surface mounted permanent magnet motor, efficiency, cogging torque, magnetic flux density distribution, transient characteristics

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