Different types of PM motors are finding applications substituting squirrel cage induction motors for its smooth control, energy efficient operations and high power density. Even though these motors are energy efficient, they are affected by ripples in the torque and cogging torque. Torque ripples are nothing but the oscillations leading to various mechanical issues like vibrations, rotor stress and noise. Factors like non sinusoidal distribution of flux, saturation, wrong selection of slots etc are creating ripples in developed torque. These ill effects are deteriorating PM motors performance in starting and steady state. Now a days reducing cogging torque and ripples in torque gained significance in the motor design. So in this work, various techniques to reduce ripples in torque and to reduce cogging torque of various PM motors has been investigated and reported.

各种类型的PM电动机正因其平滑的控制，节能的操作和高功率密度而正在寻找替代鼠笼式感应电动机的应用。即使这些电机具有高能效，它们也会受到转矩波动和齿槽转矩的影响。转矩脉动不过是导致各种机械问题（例如振动，转子应力和噪声）的振荡。磁通量的非正弦分布，饱和度，槽的选择错误等因素都会在产生的转矩中产生波动。这些不良影响使永磁电动机在启动和稳定状态下的性能下降。现在，减少齿槽转矩和转矩波动在电机设计中变得越来越重要。所以在这项工作中