Study of a Novel Annular Air-Core Reactor with High Power Density

With the rapid development of flexible DC transmission technology, the increasing capacity and voltage level of the grid puts forward higher requirements on bridge arm reactors (BARs) in terms of power density, magnetic field control, and structural optimization. Traditional cylindrical air-core reactors (CARs) limit their feasibility in high-capacity applications due to the large magnetic field radiation range. In order to improve the reactor performance and reliability, this paper proposes a new type of annular air-core reactor (AAR). The design optimizes the magnetic field distribution through the structure and significantly reduces the reactor size, while increasing the power density and reducing the magnetic field radiation. Based on the finite element method (FEM), this paper presents a multi-physics field analysis of the force and acoustic fields, and the results show that the AAR achieves significant improvements in both magnetic field confinement capability and volume reduction compared to the conventional CAR. In addition, the mechanical characterization shows that the AAR has superior structural stability and vibration resistance, which can effectively reduce the vibration and noise levels. The research in this paper provides a new theoretical basis and engineering solution for the design of reactors in large-capacity flexible DC transmission systems.