Method and apparatus for monitoring equivalent series resistance and for shunting a fuel cell
View Patent ↗A fuel cell power system comprising a fuel cell having a cathode and an anode adapted to be coupled to a fuel supply, and which is configured to produce electrical power having a current and voltage output; a controller electrically coupled with the fuel cell, and configured to selectively short the anode to the cathode of the fuel cell; and circuitry configured to measure resistance of the fuel cell in timed relation to the shorting.
1. A fuel cell power system comprising:
a plurality of fuel cells which are configured to supply power to a load, and which are configured such that at least one of the fuel cells is selectively decoupled from the load while other fuel cells continue to supply power to the load;
circuitry configured to measure equivalent series resistance in timed relation to the decoupling of at least one of the fuel cells from the load; and
circuitry configured to selectively short at least one of the fuel cells in timed relation to the decoupling of at least one of the fuel cells from the load.
2. A fuel cell power comprising:
a pair of output terminals;
a plurality of fuel cells which each have an anode which is coupled to a fuel supply, and a cathode, and wherein the respective fuel cells are selectively coupled to the output terminals, and wherein the fuel cells, in operation, convert chemical energy into electrical power which has a current and voltage output, and wherein one or more fuel cells are selectively decoupled from the output terminals while the remaining fuel cells continue to provide power to the output terminals; and
circuitry configured to measure the equivalent series resistance of one of the decoupled fuel cells, in situ, while the remaining fuel cells continue to produce electrical power, and wherein the circuitry configured to measure the equivalent series resistance of the fuel cell comprises a voltage sensor, and a current sensor which are disposed in sensing relation relative to the anode and cathode of the respective fuel cells to measure the current generated by, and voltage across, the respective fuel cells, and wherein the equivalent series resistance is determined by shorting the anode and cathode of one of the fuel cells, measuring the fuel cell voltage, and current charges at the time intervals between, before, and immediately after a short is applied, and dividing the voltage charge by the current charge.
3. A fuel cell power method comprising:
supplying power to a load using a plurality of fuel cells;
decoupling at least one of the fuel cells from the load while the remaining fuel cells continue to supply power to the load;
selectively short circuiting at least one of the fuel cells in timed relation to the decoupling of at least one of the fuel cells from the load; and
measuring equivalent series resistance of at least one of the fuel cells while power is continued to be substantially supplied to the load.