DEVELOPMENT OF A VALIDATED DIGITAL TWIN MODEL FOR POWER-SPLIT HYBRID ELECTRIC VEHICLE DYNAMICS

Abstract

A physics-based digital twin model of a power-split hybrid electric vehicle is developed to reproduce the coupled behaviour of the internal combustion engine, motor-generator units, high-voltage battery, DC-DC converter, planetary gear power-split device and longitudinal vehicle body. The model is formulated in a modular MATLAB/Simulink and Simscape environment so that each subsystem can be parameterized, monitored and validated without losing the energy interactions that govern hybrid powertrain operation. The vehicle model uses a 1575 kg vehicle mass, 0.30 m tyre radius, 75 kW engine, 25 kW MG1, 55 kW MG2, 650 V regulated DC bus and 70% initial battery state of charge. A rule-based supervisory energy management strategy is integrated with explicit mode-selection, torque-split, SOC-protection and regenerative-braking logic. Validation is carried out using a reference-response drive-cycle procedure and quantitative error metrics. The developed model tracks the 0-100 km/h speed profile with a speed RMSE of 0.76 km/h, speed MAE of 0.59 km/h and speed MAPE of 3.08%. The high-voltage battery remains within 69.61-70.25% SOC, while the battery voltage is maintained between 339 and 341 V and the DC-link voltage remains close to 650 V with a DC-link RMSE of 1.38 V. The results demonstrate stable power sharing between engine, MG1, MG2 and battery, with battery power varying from approximately -20 kW during charging/regeneration to +40 kW during traction assistance. The proposed digital twin provides a transparent and computationally practical platform for HEV performance evaluation, power-flow analysis, controller verification and future health-monitoring applications.