Insulation Optimization Design and PDIV Calculation of Hairpin Winding Motor Under Extreme Conditions

To investigate the optimal design of the insulation system for Hairpin motor under extreme conditions, partial discharge was analyzed based on Townsend discharge theory. The Partial Discharge Inception Voltage (PDIV) under different models was calculated using Paschen's law as the criterion. Referring to the simulation data, an analytical expression for electric field strength was derived via uniform field approximation. Numerical analysis methods were employed to optimize computational accuracy, with parameter optimization techniques ensuring the applicability of the derived expression across various models. Results demonstrate that approximating the 3D model of motor as a 2D equivalent significantly simplifies the computational analysis process of the insulation system. The derived analytical expression effectively adapts to different insulation thicknesses, showing excellent consistency between calculated PDIV values and simulation results. The optimal design ensures insulation reliability under extreme operating conditions while minimizing insulation volume proportion to enhance slot fill factor, thereby improving overall motor performance.