Voltage Balance Evaluation Strategy after DC-port Fault in Centralized Aircraft Ground Power Unit Based on Three-Level Neutral Point Clamped Cascaded Converter

The Aircraft Ground Power Unit(GPU) could replace the Auxiliary Power Unit (APU) in the aircraft while the aircraft is parking in the airport. Therefore, the oil-consuming and the air pollution of the APU are solved. However, the GPU is faced with the challenges of utilization, power quality, and fault-tolerance. Thus a novelty centralized aircraft GPU based on a three-level neutral point clamped cascaded converter (3LNPC-CC) is introduced to improve the utilization and power quality. Furthermore, an evaluation voltage balance strategy is proposed for the DC-port fault-tolerance of the 3LNPC-CC. Additionally, the modulation of phase shift pulse width modulation (PSPWM), and the control of double closed-loop are used in the 3LNPC-CC respectively. The simulation including the control, modulation, and fault-tolerance of the system is established to verify the feasibility and the performance itself, especially on the evaluation voltage balance strategy for the DC-port fault. Moreover, a prototype of the GPU and the relevant experiment is completed to verify the correctness and feasibility of the system and the strategy.