Structural Analysis and Design of High-Power IGBT Bridge Arm Unit for EAST Poloidal-Field Power Supply

In the Experimental Advanced Superconducting Tokamak (EAST) poloidal-field power supply (PFPS), the necessity of paralleling high-power IGBT modules within each IGBT bridge arm unit is underscored by substantial power requirements. This study aims to enhance current sharing among these modules, focusing on module layout and copper bar structure optimization. Utilizing the partial element equivalent circuit (PEEC) method, we model the stray inductance in the commutation circuit, considering the skin and proximity effects in laminated busbars. A novel input structure is proposed to improve the current sharing without affecting the unit's overall inductance, incorporating heat dissipation and dc-link capacitor layout into the bridge arm unit's design. This article's main contributions include detailed PEEC-based electromagnetic modeling and a new design enhancing current sharing in 3IGBT parallel modules, validated by multiphysics co-simulation. These simulations confirm our approach meets the system's compatibility, stress, current sharing, and temperature criteria, marking significant progress in high-power IGBT module application in fusion power systems. This article not only presents a practical solution to current-sharing challenges but also sets the groundwork for future advancements in power electronics design.