Photovoltaic‐Assisted Energy Optimization for High‐Speed Train Performance in South Africa Intercity Electric Rail Corridors

Decarbonizing the intercity rail in sub‐Saharan Africa requires the use of energy architectures that go beyond traditional grid reliance at the expense of traction performance. This paper introduces a novel photovoltaic (PV)‐assisted hybrid traction topology for a 42 km Pretoria–Sandton rail corridor in South Africa, where between‐rail PV arrays is directly drivetrack‐mounted permanent magnet synchronous motor (PMSM) roller drive; active mechanical torque assist at the wheel interface, a coupling mode not previously reported in the rail‐solar literature. The model is a multi‐domain electromechanical interface, written in MATLAB/Simulink software, which comprises the traction dynamics, MPPT controller, DC–DC power conversion, dual‐output inverter and coulomb‐counting battery state‐of‐charge (SOC) within six operational energy zones. Comparative analysis of three scenarios (grid‐only, battery‐hybrid and proposed PV‐assisted hybrid) indicates that the proposed topology supports the 160 km/h design speed at all gradient sections, whereas grid‐only operation introduces a decrease in speed, and reduces peak battery power demand by 40%. Economically, the PV‐assisted strategy reduces grid energy demand per trip that translates to a 45% reduction in cost per trip when the Eskom 2024/25 energy supply tariff of R2.2/kWh is considered. A comparison of five published rail‐PV studies shows that no prior studies has reported synchronized sensor‐triggered in‐motion PV‐to‐traction coupling at the wheel level. The indices of practical deployment, including the inter‐rail PV mounting under the dynamic axle load, the DC arc safety and rapid shutdown, with the maintenance of the roller based on the test conditions are systematically discussed. The findings indicate that distributed PV roller integration is technically and economically viable for a route to net‐zero intercity electrified rail corridors in South Africa and developing economies.