Special Session SS19

High-Speed Electrical Machines and Its Drive Systems

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Introduction:

High-frequency transformers (HFTs) are core isolation and energy-transfer components in solid-state transformers (SSTs), dual-active-bridge DC–DC converters, on-board chargers for electric vehicles, and DC collection systems for renewable energy. As wide-bandgap power devices push switching frequencies toward tens of kilohertz and beyond, the power-density and efficiency potential of HFTs is further unlocked, yet the coupling effects among electromagnetic, thermal, mechanical, fluid, acoustic, and insulation domains are amplified dramatically. At high frequencies, skin and proximity effects drive up winding AC losses, core loss and flux distribution under non-sinusoidal excitation deviate from sinusoidal assumptions, and localized hotspot temperatures interact with thermal stress to exacerbate vibration, noise, and accelerated insulation degradation. Studies on medium-voltage HFTs have shown that breakdown voltage, partial discharge inception voltage, and electrical-treeing behavior are not governed independently by frequency, temperature, or waveform shape; rather, they arise from coupled charge relaxation, dielectric-loss heating, local field enhancement, and electro-thermo-mechanical damage. Conventional design paradigms based on single-field approximations or sequential trial-and-error are increasingly inadequate for achieving verifiable co-optimality among efficiency, power density, temperature rise, insulation lifetime, and cost. This special session aims to bring together researchers and engineers from electrical, materials, mechanical, thermal, and control disciplines to exchange recent advances in multiphysics coupling mechanisms, refined modeling methods, and multi-objective optimization theories for HFTs, promoting a paradigm shift from “single-field approximation with empirical correction” toward “coupling-informed co-design.” Its significance lies in establishing a common methodological framework for the forward design of high-power-density, high-reliability, and long-lifetime HFTs, thereby providing theoretical and technical foundations for the large-scale deployment of SSTs in smart distribution grids, rail traction, ultrafast charging infrastructure, and offshore wind energy. Experts and scholars in relevant fields are cordially invited to submit manuscripts.

The topics of interest include, but are not limited to:

1. Electromagnetic–thermal–mechanical multiphysics coupling mechanisms and modeling of HFTs
2. Refined high-frequency loss calculation and magnetic characterization under non-sinusoidal excitation
3. Co-modeling and regulation of winding AC resistance, leakage inductance, and parasitic capacitance
4. Thermal management, hotspot prediction, and thermo-mechanical coupling in HFTs
5. Electromagnetic force, magnetostriction, and vibration–noise analysis under multiphysics coupling
6. High-frequency insulation degradation mechanisms, partial discharge characteristics, and insulation-structure co-design
7. Application of multi-objective optimization algorithms (genetic algorithms, NSGA-II, surrogate models) to HFT design
8. Multiphysics adaptability evaluation of core and winding materials and application of novel soft magnetic materials
9. Digital twins, condition sensing, and lifetime prediction of HFTs
10. Multiphysics design cases and experimental validation of HFTs for solid-state transformers, electric vehicles, and renewable energy applications

SS19's Session Chair:

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Assoc. Prof. Pengning Zhang, China University of Mining and Technology (Beijing), China

SS19's Session Co-chairs:

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Assoc. Prof. Bin Chen, China Three Gorges University, China

Assoc. Res. Fellow Shen Zhan, Southeast University, China

Assoc. Prof. Shuaichao Yue, Hebei University of Technology, China