覆铜实心转子感应电机二维磁场解析及等效电路参数计算OA

The rotor magnetic field distribution in copper-coated solid rotor induction motors is complex,making it difficult to visualize the internal field distribution using traditional lumped-parameter magnetic circuit analysis or to account for the influence of slip on equivalent circuit parameters.This paper focuses on solving the electromagnetic field within the copper-coated solid rotor.A subdomain analytical method in cylindrical coordinates is employed for the effects of stator slotting and slot-opening shape on the electromagnetic field.The analytical solutions for the air gap,rotor copper layer,and rotor steel are derived using 2D eddy-current finite-element analysis.Compared with the finite element method,the proposed analytical approach significantly reduces computation time by selecting appropriate harmonic orders.For the copper-coated solid-rotor induction motor,the subdomain analytical method and the traditional wave impedance method are compared with respect to equivalent circuit models,input impedance parameters,and output characteristics.The results demonstrate that the subdomain analytical method achieves greater consistency with finite element calculations across different slip conditions than the traditional wave impedance method. This paper lists the Laplace equations(for the air-gap and slot-opening subdomains),the Poisson equation(for the slot subdomain),and the Helmholtz equations(for the rotor copper layer and iron core subdomains).The general solutions for the vector magnetic potential in each subdomain are obtained.The harmonic coefficients in the Fourier series of the vector magnetic potential are determined through eight boundary conditions applied at four interfaces.Taking a 2-pole 18-slot copper-coated solid rotor induction motor as the model,the radial and tangential air-gap flux densities,rotor magnetic flux line distributions,and rotor eddy current density distributions under no-load,load,and locked-rotor conditions are calculated.The Maxwell stress torque under current source excitation is derived.The analytical results are validated using a two-dimensional eddy-current field finite-element analysis. To investigate the influence of harmonic orders on computation time and numerical errors,the harmonic orders for the air gap,slot,and slot opening are incrementally increased,and the resulting discrepancies between analytical results and finite element simulations are observed. A comparison is made with the traditional wave impedance method regarding the form of the equivalent circuit and the approach to calculating impedance parameters.The reasons for errors in the equivalent circuit parameters computed by the wave impedance method and the subdomain analytical method are compared. The following conclusions are drawn.(1)The subdomain analytical method can clearly and accurately represent the electromagnetic field distribution in copper-clad solid rotor induction motors.Selecting appropriate harmonic orders maintains computational efficiency while achieving accuracy.(2)Compared to the wave impedance method,the proposed subdomain analytical method provides more accurate calculations of equivalent circuit parameters and remains unaffected by variations in slip.