自适应限流磁饱和柔直系统桥臂耦合电抗器OA

Arm reactors,as critical components in modular multilevel converter(MMC),are predominantly implemented as air core reactors.Their fixed inductance values make it difficult to optimize and balance the current suppression per-formance and system dynamic response.To overcome this,this paper proposes a novel magnetic saturation bridge arm coupled reactor(MACR)with adaptively variable inductance.The MACR utilizes the nonlinear magnetization character-istics of soft magnetic materials and mutual coupling between windings to achieve adaptive inductance modulation under three operating conditions,namely,steady state,circulating current,and fault current,thereby effectively suppressing both circulating and fault currents.Firstly,for the magnetic saturation core structure and four winding coupling design of the MACR,the three different operating modes were analyzed from the perspective of magnetic circuit and electrical circuit equivalent models,and the analytical expressions of the equivalent inductance under corresponding operating conditions were derived.Secondly,device finite element simulation and system level co-simulation for the±800 kV voltage class were conducted.The results prove that the inductance value of the MACR remains stable during steady state operation,increases under circulating current conditions,and increases further during faults.This effectively enhances the system's ability to suppress circulating currents and limit fault currents.Finally,a small capacity MACR prototype was developed,and prototype experiments were carried out.The experimental results are consistent with the theoretical analysis,verify-ing the feasibility of the proposed topology.