Line-start permanent magnet synchronous motor ( LSPMSM) features a starting cage on the ro-tor. The small cross-sectional area of the magnetic flux path in the central region of the magnetic bridge leads to increased magnetic flux density and uneven saturation. To improve the calculation accuracy of e-lectromagnetic performance for LSPMSM

an improved magnetic network model ( MNM) accounting for non-uniform flux density in inter-pole magnetic bridges and dynamic air-gap permeance variation was de-veloped based on their magnetic circuit characteristics. This model accounts for both the uneven magnetic flux density distribution in the inter-pole magnetic bridge area and the dynamic variation of air-gap perme-ance. Additionally

the permeance changes caused by the nonlinearity of ferromagnetic materials were in-corporated into the model solution process. Taking a 7. 5 kW LSPMSM as an example

the proposed mod-el was applied to calculate and analyze its electromagnetic performance. Comparisons with other calcula- tion methods verified the correctness of the improved MNM. On this basis

the established MNM was combined with the response surface method and particle swarm optimization algorithm for multi-objective optimization of the motor’s electromagnetic performance

enabling rapid acquisition of the optimal elec-tromagnetic design scheme. For the prototype motor

the optimized scheme reduces cogging torque by 48. 14%

increases electromagnetic torque by 8 N·m

and raises back electromotive force (back-EMF) amplitude by 8 V while reducing its total harmonic distortion. The proposed research method provides a reference for the accurate calculation of electromagnetic performance and serialized optimization design of LSPMSMs.