Low-Frequency Stability Analysis of a Traction Power Supply System with Consideration of PV and ESS Penetration

As photovoltaic (PV), and energy storage system (ESS) are increasingly integrated into traction power supply system (TPSS) via back-to-back converters (BTBCs), complex hybrid structures with multiple converters and ports emerges. This complexity leads to low-frequency oscillations and threatens system stability. To address this, a detailed model considering the dynamic characteristics of BTBC, PV and ESS for multi-converter integrated TPSS is developed. Differences among various converters are taken into consideration. Subsequently, the stability analysis of a TPSS is thoroughly discussed using the determinant of the impedance return difference matrix based on the Bode plot rather than the impedance ratio method. Based on this, the oscillation frequency is clearly obtained. The sensitivity of each parameter to stability is given. Finally, the proposed detailed model is validated through hardware-in-the-loop (HIL) experiments, effectively depicting the complete dynamics of a TPSS with BTBC, PV, and ESS.