Mission Profile Emulator for Sub-Modules in CHB-BESS of Frequency Support Applications

The integration of large-scale renewable sources presents significant challenges to the frequency stability of the power grid. Battery energy storage (BES) represents a promising technology for providing short- to medium-term frequency support. However, advanced control strategies for frequency support make it complex for the transient process within the power circuit and battery clusters. These complexities can result in adverse transient mission profiles, leading to complex electricalthermal stresses on the power components and batteries. This paper proposes a control structure for the mission profile emulator (MPE), which is designed to simulate the transient behavior of sub-modules (SMs) in cascaded H-bridge converterbased battery energy storage system (CHB-BESS) of frequency support applications. The controller incorporates a virtual model that generates reference signals for the MPE in real time. The grid behavior and control strategy of frequency support are included in the virtual model to reproduce authentic transient mission profiles. The effectiveness of the proposed test scheme is validated through simulations with PLECS and down-scale experiments.