Electric Machine Design and Optimization Technologies: Challenges and Innovations in Advanced Insulation Systems

Dear Colleagues,

Amid the accelerating global transition toward electrification, there is a growing demand for electric machines with high power density, high efficiency, and high reliability. The insulation system, being a critical determinant of the performance, lifespan, and reliability of electric machines, is facing severe challenges posed by extreme temperatures, high-frequency switching, high voltages, and complex operating environments. Conventional insulating materials and design concepts are increasingly inadequate to meet the technical requirements of new-generation electric machines, such as those used in new energy vehicle drivetrains, aerospace actuation systems, and high-end industrial servo motors.

This research focuses on the direction of "Electric Machine Design and Optimization Technologies: Challenges and Innovations in Advanced Insulation Systems." Existing research achievements in this field have laid a solid foundation for further investigation, providing clear research pathways and sustained momentum for in-depth exploration of insulation technologies and the systematic enhancement of overall motor performance.

The included articles cover a comprehensive range of studies from fundamental materials to system integration, with emphasis placed on the following cutting-edge areas:

1. Development and Performance Study of Advanced Electrical Insulating Materials: This line of research explores new corona-resistant polyimide films, high-performance mica tapes, organic–inorganic nanocomposite insulating materials, as well as environmentally friendly high-temperature impregnating resins and coating varnishes. These studies aim to enhance material properties including thermal class (e.g., ≥180°C, 200°C), dielectric strength, thermal conductivity, mechanical toughness, and resistance to environmental aging.

2. Insulation Aging Mechanisms and Lifetime Modeling under Multi-Physics Coupling: Addressing complex working conditions involving coupled electrical–thermal–mechanical–environmental stresses, research thoroughly analyzes the effects of partial discharge (PD) characteristics, space charge accumulation, thermal aging, vibrational stress, and hygrothermal synergy on insulation lifespan. More accurate lifetime prediction models have been established, providing a theoretical basis for reliability design and condition assessment of electric machines.

3. Insulation Design Challenges and Countermeasures under High-Frequency Applications: Focus is placed on the severe challenges posed by steep-fronted pulse voltages (high dv/dt) generated from inverter power supplies on motor winding insulation. Investigations include electric field distribution under pulsed voltages, dielectric loss characteristics, and failure mechanisms. Corresponding optimization strategies for insulation structure are proposed, such as improving interturn and slot insulation design to suppress partial discharge and dielectric heating.

4. Intelligent Diagnostics and Condition Monitoring Technologies: Advanced sensing and data analysis techniques for online and offline assessment of the insulation health status in electric machines are presented. These include partial discharge detection and dielectric spectroscopy analysis, among others. Such technologies provide effective tools for achieving predictive and intelligent maintenance of electric machines, thereby preventing unexpected failures.

Dr. Peng Wang
Guest Editor

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• electric machine design
• advanced insulation systems
• electrical insulating materials
• insulation aging
• partial discharge
• high-frequency insulation
• dielectric loss
• condition monitoring
• intelligent diagnostics
• predictive maintenance