Investigation of 2D Nano-Structured Winding Insulation for High Torque Density Medium-Voltage Motor

Abstract

Since the introduction of mica paper and synthetic resin-based taping insulation for rotating-machines in 1950s, only evolutional improvements in their properties and processing have been made. Due to its challenging nature, much of recent insulation research has been focused on the aspect of reliability rather than performance enhancement. This paper presents the development and performance evaluation of a revolutionary nanostructured insulation in the manufacturing of large propulsion motors with game-changing torque density and payload efficiency for marine Next Generation Integrated Power System. It is demonstrated that nanostructured insulation based on 2D-platelet fillers could offer significant improvement over conventional insulation system in electrical, dielectric, thermal and mechanical properties. Optimal nanostructured insulation formation identified through a Design of Experiment study exhibits high thermal conductivity of >0.8 W/( text{m}cdot text{K} ), high breakdown strength of >40 kV/mm, low dielectric constant of less than 5.5 and low dielectric loss factor of less than 2.5% at 155°C. Voltage endurance tests on coupons with optimal formulation, in accordance with IEC 60343 standard, demonstrate satisfactory endurance life. Furthermore, a multi-physics finite-element-analysis model of the winding in a medium-voltage electric motor is established to perform electromagnetic and thermal analyses in ANSYS under various temperature boundary conditions. The study indicates a remarkable increase of 14% in torque handling capacity of a motor wound with proposed nanostructured insulation material when compared to an identical motor wound with conventional micaceous insulation.