Rapid analytical optimization of eddy current shield thickness for associated loss minimization in electrical machines

A copper or another high conductivity shield is often used in solid rotor machines for reducing armature reaction space and time harmonic induced surface eddy current losses in the rotor. Since finite element simulations can make the design process very time consuming and complicated, an analytical model for calculating the surface losses is derived in this paper. A set of equations is derived based on Maxwell´s equations for a general case and applied to a solid rotor synchronous machine. The simulation results show that the model can serve as an effective screening tool for determining the optimal shield thickness for minimizing the surface losses, especially for high speed machines operating in conjunction with power electronic converters