A Dynamic Active Fault-tolerant Control for Hybrid Advanced Traction Power Supply Device

The novel hybrid advanced traction power supply device (NH-ATPSD), which consists of a traction transformer and a “two-phase-parallel-input to single-phase-cascaded-output” (2AC-AC) converter, has been proposed recently. It provides opportunities for solving the neutral section and negative-sequence power quality problems. However, different from the single-level power electronic device with cascade structure, the negative-sequence current and healthy module overload may occur when the input- or output-module fault occurs in NH-ATPSD. Thus, a dynamic fault-tolerant control for NH-ATPSD is proposed in this paper. For input module faults, the healthy module overload is avoided by the proposed dynamic modulation coefficient, which can dynamically adjust the power allocation between output port modules. In addition, the negative-sequence current is suppressed by controlling the partial power imbalance between the 2AC input modules. For output module faults, the active bypass of faulty module and increased voltage methods are adopted to keep the rated voltage and power output. Finally, the simulation and experiment results verify the effectiveness and efficiency of the proposed control strategy under different fault types.