Performance of Electric Motor With Integrated Magnetic Spring Under Rotor Eccentricity

Recently, a novel electric motor with integrated magnetic spring (EMMS) is proposed for cyclic loads for reducing the energy consumption of these types of loads. The EMMS produces the oscillating part of the load torque in a passive way by the magnetic spring. Thereby, this reduces the energy consumption. Nevertheless, the rotor is sandwiched between two stators which complicates the manufacturing. In addition, it may introduce misalignment for the rotor resulting in rotor eccentricity. This paper investigates the impact of rotor eccentricity on the performance indicators (torque, losses, flux linkage and forces) of the EMMS. Static and dynamic rotor eccentricities are investigated. A finite element model is used to compute the performance indicators of the EMMS. It is found that 30% rotor eccentricity doesn’t affect the machine torque, losses, and flux linkage. However, it results in an increased radial force on the rotor, which may increase the vibrations of the EMMS. In addition, it will affect the lifetime of the bearings.