Electrical Insulation Stresses in PWM-driven Electric Machines


Julia Zhang, Yanyan Xie, Franco Leonardi, Alfredo Munoz and Feng Liang


This tutorial will teach the finite element modeling, mathematical modeling, and experimental testing of electrical stress distribution inside electric machine windings driven by PWM voltage excitations. The instructors will discuss: 1) industry standards on winding insulation design and testing for electric machines; 2) how to use finite element techniques to model the winding pulse voltage propagation and current distribution in individual conductors of inverter-driven machine windings; 3) mathematical modeling of voltage/current distribution in machine windings; 4) challenges and solutions in testing winding electrical stress distribution using both machine prototypes and electrified vehicle productions; 5) factors that affect the winding pulse voltage propagation, including wire distributions in slots, parasitic parameters, current level, DC bus voltage, rotor speed, etc. 6) the voltage stress map on the insulation parts along machine windings, providing support for machine insulation system design.