Zeroth-Order Vibration Analysis and Mitigation in Integral-Slot IPMSMs by Rotor Static Modulation Theory for Electrified Ship Propulsion

The general air-gap field modulation theory provides a unified principle for the magnetic field analysis of the permanent magnet synchronous motor (PMSM). The guidance for the improvement of the electromagnetic performance deserves to be investigated by the modulation theory, especially electromagnetic vibration performance. This paper proposes a zeroth-vibration analysis and mitigation method based on the rotor magnetic field static modulation theory for electrified ship integral-slot interior PMSM (IPMSM). It provides a fast and accurate solution for vibration mitigation. Firstly, the analytical model of the static modulation function is established. The static modulation process of the rotor flux density harmonics by rotor modulation notches is revealed. Then, the derivation of the zeroth-order vibration is investigated. The corresponding vibration reduction method is proposed based on the optimized static modulation function. By adopting the proposed optimized method, the dominant radial force is greatly weakened. Thus, the zeroth-order vibration performance is greatly improved. Finally, the prototype of a 72-slot/12-pole integral-slot IPMSM for an electrified ship is manufactured. Several simulation and experiment verifications are carried out to validate the theoretical analysis.