In response to growing interest in high-temperature electrolysis, CEA-Liten has developed multi-stack Solid Oxide Cell (SOC) testing equipment comprising four electrolyser stacks. Each stack includes multiple cells, and together they form a module housed within a shared thermal enclosure and connected to a balance of plant. This setup supports the development of innovative control strategies, essential due to the stacks’ sensitivity to operating conditions. To mitigate risks and costs associated with testing new strategies directly on the physical system, a Model in the Loop approach was implemented. The model replicates the real module’s characteristics and operational capabilities, allowing safe and efficient design and validation of control strategies. Various transition scenarios between operating conditions—tailored to diverse production needs and constraints—were developed and validated using the model before real-world implementation. This paper presents the model-based control methodology and compares experimental results with simulations.