Method for dissipating energy in a fuel cell generator system
View Patent ↗A method and apparatus for dissipating energy in a fuel cell generator system is provided. The method comprises determining an amount of electric power to be dissipated, operating a compressor to draw electric current as required to dissipate the determined amount of electric power, and valving the compressor to reduce the delivery of gas containing oxygen to the fuel cell stack. Valving the compressor includes restricting the flow of gas containing oxygen into the compressor, as well as venting gas containing oxygen to the atmosphere. Valving the compressor also includes inefficiently operating the compressor to reduce the flow of gas containing oxygen to the fuel cell stack. Such electrical power to be dissipated may be generated from a regenerative braking system of a vehicle, or from the minimum amount of electrical power that the fuel cell system can generate.
1. A method for dissipating electrical power in a vehicle having a fuel cell power system for generating electricity and having a regenerative braking system for converting kinetic energy into electrical energy, and said vehicle having an electrical power storage device for storing electrical energy from said regenerative braking system and for solving electrical energy to a motor in a drive train of said vehicle; said fuel cell power system including a fuel cell stack of at least one fuel cell for generating electric power and a compressor for delivering gas containing oxygen to said fuel cell stack, said method comprising:
determining an amount of said electrical power to be dissipated by summing the minimum amount of electrical power that can be generated by said fuel cell system and said regenerative braking system, and subtracting an amount of electrical power required by said vehicle and subtracting the amount of electrical power capable of being stored in said electrical power storage device;
operating said compressor to draw electric current as required to dissipate said amount of said electrical power; and
valving said compressor to reduce delivery of gas to said fuel cell stack.
2. The method of claim 1 wherein valving said compressor to reduce delivery of gas to said fuel cell stack comprises restricting the flow of said gas.
3. The method of claim 2 wherein the step of restricting the flow of gas containing oxygen further comprises restricting an input of said compressor and wherein said compressor creates a vacuum.
4. The method of claim 1 wherein valving said compressor comprises venting an output of said compressor.
5. The method of claim 4 wherein said compressor is vented to the atmosphere.
6. The method of claim 1 wherein the step of operating said compressor to draw an electrical power load equivalent to said determined amount of said electrical power to be dissipated further comprises generating a feed-forward output signal to adjust said compressor speed to draw an electrical load equivalent to said determined amount of said electrical power to be dissipated.
7. The method of claim 1 wherein the step of valving said compressor further comprises inefficiently operating said compressor to reduce delivery of said gas to said fuel cell stack.