The global shift toward sustainable mobility has highlighted vehicle retrofitting as a pivotal strategy for the rapid decarbonization of the transport sector. Within the framework of the Electrified Retrofit Smart System (ERSS) project by eXaV, this thesis addresses the challenge of developing a high-performance Vehicle Control Unit (VCU) capable of managing the complexities of modern electric powertrains. The research focuses on the design and implementation of a proprietary Rapid Control Prototyping (RCP) toolchain that enables the deployment of model-based control laws onto a heterogeneous architecture (RT-FPGA). The research implements a layered software paradigm to decouple control logic from hardware abstraction, enabling a deterministic interface between high-level algorithms and industrial- grade real-time signal processing.