Stability Analysis of Co-Phase Traction Power Supply System Based on dq-Frame Impedance

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Abstract
In order to improve power quality and realize uninterrupted power supply, the co-phase traction power supply system (CTPSS) is developed. However, CTPSS introduces large-scale power electronics on the power supply side of the train-grid system, which makes the train-grid electrical coupling relationship complicated and prone to system instability. To explore the problem, the dq-frame impedance of CTPSS is derived in this paper. Neglecting DC voltage fluctuations, the co-phase supply units (CPSUs) can be equated to single-phase inverters, while the electric multiple units (EMUs) are equated to single-phase rectifiers. Then, the modeling approach is verified by frequency-domain simulation based on the impedance-frequency sweep method for single-phase systems. In addition, the stability of CTPSS is discussed on the basis of the Generalized Nyquist Stability Criterion. Finally, the CTPSS model is constructed in MATLAB simulation platform, and the experimental results verify the correctness of the theoretical model.
Funding Information
  • National Natural Science Foundation of China