Electricity is a key energy vector in the global shift away from fossil fuels. It is distributed via AC grids connecting power plants to consumers over long distances. Transition policies highlight using medium-scale, medium-voltage distributed generation and storage systems, like France's mandate to cover parking lots with photovoltaic panels. But, these intermediary systems generate DC energy, requiring conversion to AC for grid integration. Medium-voltage direct current (MVDC) grids are an interesting solution for integrating these distributed systems. They offer enhanced energy efficiency, control, and reliability. However, non-standard power converters in DC grids pose issues such as interoperability, high development costs and obsolescence. Our project proposes to improve the modular multilevel converter (MMC) to create standard, modular, robust and scalable power interfaces. The MMC is a converter topology using low-voltage modules in series. This offers genericity in terms of voltage levels. Known for its reliability and robustness, its main drawback is its complex control and data architectures, requiring expensive centralized supervision system. This limits the competitiveness of the MMC for MVDC applications. Our CARROTS project aims to design an open-source generic MMC with masterless cooperative control and a peer-to-peer communication network, suitable for MVDC applications. This 48-month PRCE project involves four research laboratories and a start-up in an interdisciplinary collaboration. We will explore the power, control and data aspects of this challenging proposition while integrating it into an open-source power electronics framework. CARROTS aims to create the first open-source MMC to support international research initiatives, and stimulate innovation in the industry.