Modular Multilevel Converters for Next-Generation Electric Arc Furnaces in Steelmaking Electrification

Ongoing effort towards the decarbonization of steelmaking requires the widespread adoption of Electric Arc Furnaces (EAFs). Due to the variability of load and its effect on the upstream grid, the adoption of inverter-based solutions is largely beneficial, yet not widespread. Due to the different requirements in terms of arc operating voltages which depend on plant power ratings, the Modular Multilevel Converter (MMC) is a prominent candidate. However, several challenges need to be solved, such as the high reactive power, variability, and load imbalance, all of which strongly affect the stability of the voltage of the modules. The adoption of an MMC for EAF supply is proposed and analyzed in this work, starting from a brief review of the existing solutions. The peculiarities of this application related to its design and control are reported for the first time. An effective current control strategy is also proposed, allowing to achieve excellent control performance. Simulations based on realistic system parameters and conditions demonstrate the feasibility and effectiveness of the proposal.