• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.4
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• pp.293-302
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• 2020

This study proposes a triple-loop current control method for the auxiliary power unit of fuel cell trains. The auxiliary power unit of fuel cell trains has a grid-connected function when power is supplied to the utility grid. Moreover, the auxiliary power unit of trains has a 1500 V DC link voltage; thus, PWM frequency cannot be increased to a high frequency. Owing to this low PWM frequency condition, creating a triple-loop design is difficult. In this study, a triple-loop controller is developed for a capacitor voltage controller in standalone mode that operates as an auxiliary power supply for trains and for a grid current controller in grid control mode with an inner capacitor voltage controller. The voltage controller employs an inductor current controller inner loop. To overcome low PWM frequency, a design method for the bandwidth of the capacitor voltage controller considering the bandwidth of the inner inductor current controller is described. The effectiveness of the proposed method is proven using PSIM simulation.