Fuel cell system and method for limiting current thereof

摘要

In a fuel cell system comprising a fuel cell with plural cells and performing processing for limiting a supply current to a load by performing a compensation computation with respect to a system-request current corresponding to a system-request power requested by the system based on the lowest cell voltage in the cells, the compensation computation being performed for limiting the supply current through a PI compensation using, as a reference value, a current value of the system-request current as of the time when the lowest cell voltage falls below a predetermined lowest-cell-voltage acceptable value, values for gains in the PI compensation for limiting the supply current are different from values for gains in the PI compensation for restoring the supply current. The system-request current can be securely limited in any operation statuses, and in addition, the supply current can be made rapidly responsive during the limitation of the current, while the supply current can be stably converged during the current restoration.

主权项

1. A fuel cell system comprising a fuel cell with a plurality of cells and a controller for performing processing for limiting a supply current to be supplied to a load by performing a compensation computation with respect to a system-request current corresponding to a system-request power requested by the system based on a lowest cell voltage in the cells, the controller being programmed to:
perform the compensation computation for limiting the supply current through a proportional integral compensation using, as a reference value, a current value of the system-request current as of the time when the lowest cell voltage falls below a predetermined lowest-cell-voltage acceptable value, wherein values for gains in the proportional integral compensation for decreasing the supply current is different from values for gains in the proportional integral compensation for increasing the supply current, and wherein the gains in the proportional integral compensation for increasing the supply current are smaller than the gains in the proportional integral compensation for decreasing the supply current.