The development of hybrid electric propulsion systems offers significant opportunities to enhance vehicle efficiency and reduce greenhouse gas emissions, particularly for heavy-duty vehicles. This thesis explores the integration of advanced energy storage systems, including batteries, supercapacitors, and fuel cells, within electric vehicles. The primary goal is to optimize energy management strategies and then prepare the vehicle model and control strategies for Hardware-in-the-Loop (HIL) testing to validate these systems under realistic conditions. Initially, the study focuses on a Battery Electric Vehicle (BEV) model using a BYD K9 series bus as the baseline. The simulation environment replicates the vehicle's dynamics and integrates various control strategies.