Design and Control of a Variable Inductor for Power Grid Applications

Variable inductors provide an additional degree of freedom in the design of an electrical system and can therefore make a significant contribution to its improvement. This paper presents an improved design of a parallel circuit using variable inductors for applications in power grid applications. A Power-Hardware-in-the-Loop (P-HiL) system for grid devices is presented as a concrete application. The design of the used parallel circuit is compared to design approaches using a single variable inductor. 3D FEM simulations were used to verify the results. Furthermore, a control system for variable inductors is presented. In particular, challenges relating to feedback from the main winding to the auxiliary winding are addressed and design approaches are discussed and compared.