Stress Analysis of Inverter-Fed Induction Motor Considering Anisotropic Magnetization and Magnetostrictive Properties

Inverter-fed induction motors generate large vibration and noise because of the Maxwell electromagnetic stress between stator and rotor, magnetostrictive stress of silicon steel and the harmonics in load current. On the vibration reduction study of motor cores, many researchers kept their eyes on control strategy. However, they did not compute stress of inverter-fed induction motor under sinusoidal and harmonic excitations. The nonoriented silicon steel in motor cores shows remarkably anisotropic magnetization and magnetostrictive properties under sinusoidal and harmonic excitations. Thus, in order to compute motor stress accurately, anisotropic magnetic properties must be considered. First, anisotropic property of silicon steel under sinusoidal and harmonic excitations is tested to support the stress computation. Then, an electromagneto-mechanical coupled model for motors considering anisotropic magnetization and magnetostrictive properties is proposed and stress distribution of motor cores is calculated. Finally, the frequency spectrum of the stress is analyzed to provide the theoretical basis for further research of inverter-fed induction motor vibration and noise reduction.