Cathode flow split control and pressure control for a vehicle fuel cell power system
AssigneeGM Global Technology Operations LLC
InventorsYanyan Zhang, Joseph Mussro
Life of this patent
Estimating the term…
Abstract
Devices and methods to control a cathode backpressure valve and a bypass valve in a vehicle fuel cell system. A feedforward-based control strategy is used to control the cathode backpressure valve. The control over the bypass valve is integrated into the control over the cathode backpressure valve. Such a control strategy acts in a predictive manner to improve valve response to transitory cathode pressure and bypass flow split setpoints in the system.
Claims20
A vehicle fuel cell system comprising:
- a fuel cell stack defining at least one anode flowpath and at least one cathode flowpath therein;
- a backpressure valve fluidly connected to an outlet of said at least one cathode flowpath;
- a bypass valve configured to provide selective fluid bypass around said at least one cathode flowpath;
- and
- a controller configured regulate a flow and a pressure of a fuel cell stack through the simultaneous control of both said backpressure valve and said bypass valve, said controller comprising at least one processor and a non-transitory memory such that instructions stored in said memory are executed by said at least one processor to control positions of said backpressure valve and said bypass valve to simultaneously satisfy a backpressure setpoint and a flow setpoint through utilization of:
- a feedforward-based control strategy to control gas pressure in said fuel cell stack by regulating the position of said backpressure valve, wherein said feedforward-based control strategy utilizes a stack pressure setpoint, a stack pressure feedback value and a feedforward backpressure valve value corresponding to a position of said backpressure valve;
- at least one pressure drop model and a valve position model for said backpressure valve to determine said feedforward backpressure valve value;
- and
- a valve position model for said bypass valve using said stack pressure feedback value, at least one pressure drop model for said bypass valve, a bypass flow setpoint, and a feedback bypass flow temperature value to regulate the position of said bypass valve.
A fuel cell system controller coupled to a cathode flowpath backpressure valve and a cathode flowpath bypass valve configured to simultaneously satisfy a stack flow setpoint and a stack pressure setpoint of a cathode flowpath in a fuel cell systemthe controller comprising:
- at least one processor;
- and
- a non-transitory memory cooperative with said at least one processor to store instructions that when executed by said at least one processor cause said at least one processor to:
- calculate a feedforward backpressure valve value utilizing at least one pressure drop model and a backpressure valve position model,
- calculate a backpressure valve control command using said feedforward backpressure valve value, said stack pressure setpoint, and a stack pressure feedback value,
- calculate a bypass valve control command from a bypass valve position model using at least one pressure drop model, a bypass flow setpoint, and a feedback bypass flow temperature wherein said at least one pressure drop model includes said stack pressure feedback value,
- regulate a position of said backpressure valve using said backpressure valve control command to meet said stack pressure setpoint, and
- regulate a position of said by-pass valve using said bypass valve control command to meet said stack flow setpoint simultaneously with the regulation of the position of said backpressure valve.
A method of controlling a cathode flowpath of a vehicular fuel cell system by simultaneously satisfying a stack flow setpoint and a stack pressure setpoint of said cathode flowpath that includes both a cathode flowpath backpressure valve and a cathode flowpath bypass valve such that said backpressure valve is commanded to meet said stack pressure setpoint while said bypass valve is commanded to meet said stack flow setpoint, said method comprising:
- utilizing, by at least one processor, a feedforward-based control strategy to control gas pressure in a fuel cell stack by regulating a position of said backpressure valve connected to an outlet of said fuel cell stack, wherein said feedforward-based control strategy utilizes a stack pressure setpoint, a stack pressure feedback value and a feedforward backpressure valve value corresponding to a position of said backpressure valve;
- determining said feedforward backpressure valve value using at least one pressure drop model and a valve position model for said backpressure valve;
- and
- generating a bypass valve control command that simultaneously regulates a position of said bypass valve to control a flow split between a flowpath in said stack with said position of said backpressure valve and said bypass valve, wherein said bypass valve control command is generated from a valve position model for the bypass valve using said stack pressure feedback value, said at least one pressure drop model for said bypass valve, a bypass flow setpoint, and a feedback bypass flow temperature value.
Dependencies are inferred from the claim text.